diff --git a/.rector.php b/.rector.php
index ef58b2e0f..e8ddc5b55 100644
--- a/.rector.php
+++ b/.rector.php
@@ -4,12 +4,14 @@
 
 use Rector\CodingStyle\Rector\ClassMethod\MakeInheritedMethodVisibilitySameAsParentRector;
 use Rector\Config\RectorConfig;
+use Rector\DeadCode\Rector\ClassMethod\RemoveUnusedPrivateMethodRector;
 use Rector\DeadCode\Rector\If_\RemoveAlwaysTrueIfConditionRector;
+use Rector\Privatization\Rector\ClassMethod\PrivatizeFinalClassMethodRector;
 
 return RectorConfig::configure()
     ->withPaths([
         __DIR__ . '/src',
-        #__DIR__ . '/tests',
+        __DIR__ . '/tests',
     ])
     ->withSkip([
         MakeInheritedMethodVisibilitySameAsParentRector::class => [
@@ -18,6 +20,12 @@
         RemoveAlwaysTrueIfConditionRector::class => [
             __DIR__ . '/src/N98/Magento/Initializer.php',
         ],
+        RemoveUnusedPrivateMethodRector::class => [
+            __DIR__ . '/tests/N98/Magento/Command/System/Setup/IncrementalCommandTest.php',
+        ],
+        PrivatizeFinalClassMethodRector::class => [
+            __DIR__ . '/tests/N98/Magento/Command/System/Setup/IncrementalCommandTest.php',
+        ],
     ])
     ->withPreparedSets(
         true,
@@ -34,8 +42,6 @@
         true,
         false,
         true,
-        true,
-        true,
         true
     )
     ->withTypeCoverageLevel(0);
diff --git a/src/N98/Magento/Command/System/Setup/ChangeVersionCommand.php b/src/N98/Magento/Command/System/Setup/ChangeVersionCommand.php
index 9831ae2e9..0c04eabff 100644
--- a/src/N98/Magento/Command/System/Setup/ChangeVersionCommand.php
+++ b/src/N98/Magento/Command/System/Setup/ChangeVersionCommand.php
@@ -37,10 +37,10 @@ protected function execute(InputInterface $input, OutputInterface $output): int
             return Command::INVALID;
         }
 
-        $moduleVersion = $input->getArgument('version');
-        $moduleName = $this->getModule($input);
-        $setupName = $input->getArgument('setup');
-        $moduleSetups = $this->getModuleSetupResources($moduleName);
+        $moduleVersion  = $input->getArgument('version');
+        $moduleName     = $this->getModule($input);
+        $setupName      = $input->getArgument('setup');
+        $moduleSetups   = $this->getModuleSetupResources($moduleName);
 
         if ($moduleSetups === []) {
             $output->writeln(sprintf('No setup resources found for module: "%s"', $moduleName));
@@ -63,7 +63,7 @@ protected function execute(InputInterface $input, OutputInterface $output): int
     public function updateSetupResource(string $moduleName, string $setupResource, string $version, OutputInterface $output): void
     {
         /** @var Mage_Core_Model_Resource_Resource $mageCoreModelAbstract */
-        $mageCoreModelAbstract = Mage::getModel('core/resource');
+        $mageCoreModelAbstract = Mage::getResourceSingleton('core/resource');
 
         $mageCoreModelAbstract->setDbVersion($setupResource, $version);
         $mageCoreModelAbstract->setDataVersion($setupResource, $version);
diff --git a/tests/N98/Magento/Application/ConfigFileTest.php b/tests/N98/Magento/Application/ConfigFileTest.php
index a5d75b335..d381d8b3c 100644
--- a/tests/N98/Magento/Application/ConfigFileTest.php
+++ b/tests/N98/Magento/Application/ConfigFileTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 /*
  * this file is part of magerun
  *
@@ -18,51 +20,40 @@
  * @covers  N98\Magento\Application\ConfigFile
  * @package N98\Magento\Application
  */
-class ConfigFileTest extends TestCase
+final class ConfigFileTest extends TestCase
 {
-    /**
-     * @test
-     */
-    public function creation()
+    public function testCreation()
     {
         $configFile = new ConfigFile();
-        self::assertInstanceOf(ConfigFile::class, $configFile);
+        $this->assertInstanceOf(ConfigFile::class, $configFile);
 
         $configFile = ConfigFile::createFromFile(__FILE__);
-        self::assertInstanceOf(ConfigFile::class, $configFile);
+        $this->assertInstanceOf(ConfigFile::class, $configFile);
     }
 
-    /**
-     * @test
-     */
-    public function applyVariables()
+    public function testApplyVariables()
     {
         $configFile = new ConfigFile();
         $configFile->loadFile('data://,- %root%');
         $configFile->applyVariables('root-folder');
 
-        self::assertSame(['root-folder'], $configFile->toArray());
+        $this->assertSame(['root-folder'], $configFile->toArray());
     }
 
-    /**
-     * @test
-     */
-    public function mergeArray()
+    public function testMergeArray()
     {
         $configFile = new ConfigFile();
         $configFile->loadFile('data://,- bar');
+
         $result = $configFile->mergeArray(['foo']);
 
-        self::assertSame(['foo', 'bar'], $result);
+        $this->assertSame(['foo', 'bar'], $result);
     }
 
-    /**
-     * @test
-     */
-    public function parseEmptyFile()
+    public function testParseEmptyFile()
     {
         $this->expectException(RuntimeException::class);
-        $this->expectExceptionMessage('Failed to parse config-file \'data://,\'');
+        $this->expectExceptionMessage("Failed to parse config-file 'data://,'");
         $configFile = new ConfigFile();
         $configFile->loadFile('data://,');
         $this->addToAssertionCount(1);
@@ -70,10 +61,7 @@ public function parseEmptyFile()
         self::fail('An expected exception has not been thrown.');
     }
 
-    /**
-     * @test
-     */
-    public function invalidFileThrowsException()
+    public function testInvalidFileThrowsException()
     {
         $this->expectException(InvalidArgumentException::class);
         @ConfigFile::createFromFile(':');
diff --git a/tests/N98/Magento/Application/ConfigTest.php b/tests/N98/Magento/Application/ConfigTest.php
index 51a79c72b..bdd5296a9 100644
--- a/tests/N98/Magento/Application/ConfigTest.php
+++ b/tests/N98/Magento/Application/ConfigTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 /*
  * @author Tom Klingenberg <https://github.com/ktomk>
  */
@@ -25,82 +27,72 @@
  * @covers  N98\Magento\Application\Config
  * @package N98\Magento\Application
  */
-class ConfigTest extends TestCase
+final class ConfigTest extends TestCase
 {
-    /**
-     * @test
-     */
-    public function creation()
+    public function testCreation()
     {
         $config = new Config();
-        self::assertInstanceOf(__NAMESPACE__ . '\\Config', $config);
+        $this->assertInstanceOf(__NAMESPACE__ . '\\Config', $config);
     }
 
-    /**
-     * @test
-     */
-    public function loader()
+    public function testLoader()
     {
         $config = new Config();
 
         try {
             $config->load();
             self::fail('An expected exception was not thrown');
-        } catch (ErrorException $e) {
-            self::assertEquals('Configuration not yet fully loaded', $e->getMessage());
+        } catch (ErrorException $errorException) {
+            $this->assertSame('Configuration not yet fully loaded', $errorException->getMessage());
         }
 
-        self::assertEquals([], $config->getConfig());
+        $this->assertSame([], $config->getConfig());
 
-        $loader = $config->getLoader();
-        self::assertInstanceOf(__NAMESPACE__ . '\\ConfigurationLoader', $loader);
-        self::assertSame($loader, $config->getLoader());
+        $configurationLoader = $config->getLoader();
+        $this->assertInstanceOf(__NAMESPACE__ . '\\ConfigurationLoader', $configurationLoader);
+        $this->assertSame($configurationLoader, $config->getLoader());
 
-        $loader->loadStageTwo('');
+        $configurationLoader->loadStageTwo('');
         $config->load();
 
-        self::assertIsArray($config->getConfig());
-        self::assertGreaterThan(4, count($config->getConfig()));
+        $this->assertIsArray($config->getConfig());
+        $this->assertGreaterThan(4, count($config->getConfig()));
 
-        $config->setLoader($loader);
+        $config->setLoader($configurationLoader);
     }
 
     /**
      * config array setter is used in some tests on @see \N98\Magento\Application::setConfig()
-     *
-     * @test
      */
-    public function setConfig()
+    public function testSetConfig()
     {
         $config = new Config();
         $config->setConfig([0, 1, 2]);
+
         $actual = $config->getConfig();
-        self::assertSame($actual[1], 1);
+        $this->assertSame(1, $actual[1]);
     }
 
-    /**
-     * @test
-     */
-    public function configCommandAlias()
+    public function testConfigCommandAlias()
     {
         $config = new Config();
         $input = new ArgvInput();
         $actual = $config->checkConfigCommandAlias($input);
-        self::assertInstanceOf(InputInterface::class, $actual);
+        $this->assertInstanceOf(InputInterface::class, $actual);
 
         $saved = $_SERVER['argv'];
         {
             $config->setConfig(['commands' => ['aliases' => [['list-help' => 'list --help']]]]);
-            $definition = new InputDefinition();
-            $definition->addArgument(new InputArgument('command'));
+            $inputDefinition = new InputDefinition();
+            $inputDefinition->addArgument(new InputArgument('command'));
 
             $argv = ['/path/to/command', 'list-help'];
             $_SERVER['argv'] = $argv;
-            $input = new ArgvInput($argv, $definition);
-            self::assertSame('list-help', (string) $input);
+            $input = new ArgvInput($argv, $inputDefinition);
+            $this->assertSame('list-help', (string) $input);
             $actual = $config->checkConfigCommandAlias($input);
-            self::assertSame('list-help', $actual->getFirstArgument());
-            self::assertSame('list-help --help', (string) $actual);
+            $this->assertSame('list-help', $actual->getFirstArgument());
+            $this->assertSame('list-help --help', (string) $actual);
         }
         $_SERVER['argv'] = $saved;
 
@@ -108,13 +100,10 @@ public function configCommandAlias()
 
         $config->registerConfigCommandAlias($command);
 
-        self::assertSame(['list-help'], $command->getAliases());
+        $this->assertSame(['list-help'], $command->getAliases());
     }
 
-    /**
-     * @test
-     */
-    public function customCommands()
+    public function testCustomCommands()
     {
         $configArray = [
             'commands' => [
@@ -125,10 +114,10 @@ public function customCommands()
             ],
         ];
 
-        $output = new BufferedOutput();
-        $output->setVerbosity($output::VERBOSITY_DEBUG);
+        $bufferedOutput = new BufferedOutput();
+        $bufferedOutput->setVerbosity($bufferedOutput::VERBOSITY_DEBUG);
 
-        $config = new Config([], false, $output);
+        $config = new Config([], false, $bufferedOutput);
         $config->setConfig($configArray);
 
         /** @var Application|MockObject $application */
@@ -138,10 +127,7 @@ public function customCommands()
         $config->registerCustomCommands($application);
     }
 
-    /**
-     * @test
-     */
-    public function registerCustomAutoloaders()
+    public function testRegisterCustomAutoloaders()
     {
         $array = ['autoloaders'      => ['$prefix' => '$path'], 'autoloaders_psr4' => ['$prefix\\' => '$path']];
 
@@ -149,30 +135,27 @@ public function registerCustomAutoloaders()
             '<debug>Registered PSR-0 autoloader </debug> $prefix -> $path' . "\n" .
             '<debug>Registered PSR-4 autoloader </debug> $prefix\\ -> $path' . "\n";
 
-        $output = new BufferedOutput();
+        $bufferedOutput = new BufferedOutput();
 
-        $config = new Config([], false, $output);
+        $config = new Config([], false, $bufferedOutput);
         $config->setConfig($array);
 
-        $autloader = new ClassLoader();
-        $config->registerCustomAutoloaders($autloader);
+        $classLoader = new ClassLoader();
+        $config->registerCustomAutoloaders($classLoader);
 
-        $output->setVerbosity($output::VERBOSITY_DEBUG);
-        $config->registerCustomAutoloaders($autloader);
+        $bufferedOutput->setVerbosity($bufferedOutput::VERBOSITY_DEBUG);
+        $config->registerCustomAutoloaders($classLoader);
 
-        self::assertSame($expected, $output->fetch());
+        $this->assertSame($expected, $bufferedOutput->fetch());
     }
 
-    /**
-     * @test
-     */
-    public function loadPartialConfig()
+    public function testLoadPartialConfig()
     {
         $config = new Config();
-        self::assertEquals([], $config->getDetectSubFolders());
+        $this->assertSame([], $config->getDetectSubFolders());
         $config->loadPartialConfig(false);
         $actual = $config->getDetectSubFolders();
-        self::assertIsArray($actual);
-        self::assertNotEquals([], $actual);
+        $this->assertIsArray($actual);
+        $this->assertNotSame([], $actual);
     }
 }
diff --git a/tests/N98/Magento/Application/ConfigurationLoaderTest.php b/tests/N98/Magento/Application/ConfigurationLoaderTest.php
index e030b26af..52a03237c 100644
--- a/tests/N98/Magento/Application/ConfigurationLoaderTest.php
+++ b/tests/N98/Magento/Application/ConfigurationLoaderTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 /**
  * this file is part of magerun
  *
@@ -11,14 +13,11 @@
 use N98\Magento\Command\TestCase;
 use Symfony\Component\Console\Output\NullOutput;
 
-class ConfigurationLoaderTest extends TestCase
+final class ConfigurationLoaderTest extends TestCase
 {
-    /**
-     * @test
-     */
-    public function creation()
+    public function testCreation()
     {
-        $loader = new ConfigurationLoader([], false, new NullOutput());
-        self::assertInstanceOf(__NAMESPACE__ . '\\ConfigurationLoader', $loader);
+        $configurationLoader = new ConfigurationLoader([], false, new NullOutput());
+        $this->assertInstanceOf(__NAMESPACE__ . '\\ConfigurationLoader', $configurationLoader);
     }
 }
diff --git a/tests/N98/Magento/ApplicationTest.php b/tests/N98/Magento/ApplicationTest.php
index 36d10ba79..a7c098aa8 100644
--- a/tests/N98/Magento/ApplicationTest.php
+++ b/tests/N98/Magento/ApplicationTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento;
 
 use Composer\Autoload\ClassLoader;
@@ -15,7 +17,7 @@
 use Symfony\Component\Console\Tester\CommandTester;
 use Symfony\Component\Yaml\Yaml;
 
-class ApplicationTest extends TestCase
+final class ApplicationTest extends TestCase
 {
     public function testExecute()
     {
@@ -27,22 +29,22 @@ public function testExecute()
         $application = require __DIR__ . '/../../../src/bootstrap.php';
         $application->setMagentoRootFolder($this->getTestMagentoRoot());
 
-        self::assertInstanceOf(Application::class, $application);
+        $this->assertInstanceOf(Application::class, $application);
         $loader = $application->getAutoloader();
-        self::assertInstanceOf(ClassLoader::class, $loader);
+        $this->assertInstanceOf(ClassLoader::class, $loader);
 
         /**
          * Check version
          */
-        self::assertEquals(Application::APP_VERSION, trim(file_get_contents(__DIR__ . '/../../../version.txt')));
+        $this->assertSame(Application::APP_VERSION, trim(file_get_contents(__DIR__ . '/../../../version.txt')));
 
         /* @var $loader \Composer\Autoload\ClassLoader */
         $prefixes = $loader->getPrefixesPsr4();
-        self::assertArrayHasKey('N98\\', $prefixes);
+        $this->assertArrayHasKey('N98\\', $prefixes);
 
         $distConfigArray = Yaml::parse(file_get_contents(__DIR__ . '/../../../config.yaml'));
 
-        $configArray = ['autoloaders' => ['N98MagerunTest' => __DIR__ . '/_ApplicationTestSrc'], 'commands' => ['customCommands' => [0 => 'N98MagerunTest\TestDummyCommand'], 'aliases' => [['cl' => 'cache:list']]], 'init' => ['options' => ['config_model' => 'N98MagerunTest\AlternativeConfigModel']]];
+        $configArray = ['autoloaders' => ['N98MagerunTest' => __DIR__ . '/_ApplicationTestSrc'], 'commands' => ['customCommands' => [0 => \N98MagerunTest\TestDummyCommand::class], 'aliases' => [['cl' => 'cache:list']]], 'init' => ['options' => ['config_model' => \N98MagerunTest\AlternativeConfigModel::class]]];
 
         $application->setAutoExit(false);
         $application->init(ArrayFunctions::mergeArrays($distConfigArray, $configArray));
@@ -50,27 +52,27 @@ public function testExecute()
 
         // Check if autoloaders, commands and aliases are registered
         $prefixes = $loader->getPrefixes();
-        self::assertArrayHasKey('N98MagerunTest', $prefixes);
+        $this->assertArrayHasKey('N98MagerunTest', $prefixes);
 
         $testDummyCommand = $application->find('n98mageruntest:test:dummy');
-        self::assertInstanceOf('\N98MagerunTest\TestDummyCommand', $testDummyCommand);
+        $this->assertInstanceOf(\N98MagerunTest\TestDummyCommand::class, $testDummyCommand);
 
         $commandTester = new CommandTester($testDummyCommand);
         $commandTester->execute(
             ['command'    => $testDummyCommand->getName()],
         );
-        self::assertStringContainsString('dummy', $commandTester->getDisplay());
-        self::assertTrue($application->getDefinition()->hasOption('root-dir'));
+        $this->assertStringContainsString('dummy', $commandTester->getDisplay());
+        $this->assertTrue($application->getDefinition()->hasOption('root-dir'));
 
         // Test alternative config model
         $application->initMagento();
         if (version_compare(Mage::getVersion(), '1.7.0.2', '>=')) {
             // config_model option is only available in Magento CE >1.6
-            self::assertInstanceOf('\N98MagerunTest\AlternativeConfigModel', Mage::getConfig());
+            $this->assertInstanceOf(\N98MagerunTest\AlternativeConfigModel::class, Mage::getConfig());
         }
 
         // check alias
-        self::assertInstanceOf(ListCommand::class, $application->find('cl'));
+        $this->assertInstanceOf(ListCommand::class, $application->find('cl'));
     }
 
     public function testPlugins()
@@ -88,7 +90,7 @@ public function testPlugins()
         $application->init($injectConfig);
 
         // Check for module command
-        self::assertInstanceOf('TestModule\FooCommand', $application->find('testmodule:foo'));
+        $this->assertInstanceOf(\TestModule\FooCommand::class, $application->find('testmodule:foo'));
     }
 
     public function testComposer()
@@ -115,6 +117,6 @@ public function testComposer()
         $application->init();
 
         // Check for module command
-        self::assertInstanceOf('Acme\FooCommand', $application->find('acme:foo'));
+        $this->assertInstanceOf(\Acme\FooCommand::class, $application->find('acme:foo'));
     }
 }
diff --git a/tests/N98/Magento/Command/Admin/User/ChangePasswordCommandTest.php b/tests/N98/Magento/Command/Admin/User/ChangePasswordCommandTest.php
index 66207e9ad..8d6533122 100644
--- a/tests/N98/Magento/Command/Admin/User/ChangePasswordCommandTest.php
+++ b/tests/N98/Magento/Command/Admin/User/ChangePasswordCommandTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\Admin\User;
 
 use N98\Magento\Command\TestCase;
@@ -8,13 +10,15 @@
 /**
  * Class ChangePasswordCommandTest
  */
-class ChangePasswordCommandTest extends TestCase
+final class ChangePasswordCommandTest extends TestCase
 {
-    protected $command;
-    protected $userModel;
-    protected $commandName = 'admin:user:change-password';
+    private $command;
+
+    private $userModel;
+
+    private $commandName = 'admin:user:change-password';
 
-    public function setUp(): void
+    protected function setUp(): void
     {
         $this->command = $this->getMockBuilder(ChangePasswordCommand::class)
             ->setMethods(['getUserModel'])
@@ -33,7 +37,7 @@ public function setUp(): void
     public function testCanChangePassword()
     {
         $this->userModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('loadByUsername')
             ->with('aydin')
             ->willReturn($this->userModel);
@@ -44,15 +48,16 @@ public function testCanChangePassword()
             ->willReturn(2);
 
         $this->userModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('validate');
 
         $this->userModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('save');
 
         $application = $this->getApplication();
         $application->add($this->command);
+
         $command = $this->getApplication()->find($this->commandName);
 
         $commandTester = new CommandTester($command);
@@ -60,13 +65,13 @@ public function testCanChangePassword()
             ['command'   => $command->getName(), 'username'  => 'aydin', 'password'  => 'password'],
         );
 
-        self::assertStringContainsString('Password successfully changed', $commandTester->getDisplay());
+        $this->assertStringContainsString('Password successfully changed', $commandTester->getDisplay());
     }
 
     public function testReturnEarlyIfUserNotFound()
     {
         $this->userModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('loadByUsername')
             ->with('notauser')
             ->willReturn($this->userModel);
@@ -78,11 +83,12 @@ public function testReturnEarlyIfUserNotFound()
 
         $application = $this->getApplication();
         $application->add($this->command);
+
         $command = $this->getApplication()->find($this->commandName);
 
         $commandTester = new CommandTester($command);
         $commandTester->execute(['command'   => $command->getName(), 'username'  => 'notauser']);
 
-        self::assertStringContainsString('User was not found', $commandTester->getDisplay());
+        $this->assertStringContainsString('User was not found', $commandTester->getDisplay());
     }
 }
diff --git a/tests/N98/Magento/Command/Admin/User/ChangeStatusCommandTest.php b/tests/N98/Magento/Command/Admin/User/ChangeStatusCommandTest.php
index ff48e700d..431755d83 100644
--- a/tests/N98/Magento/Command/Admin/User/ChangeStatusCommandTest.php
+++ b/tests/N98/Magento/Command/Admin/User/ChangeStatusCommandTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\Admin\User;
 
 use N98\Magento\Command\TestCase;
@@ -9,13 +11,15 @@
 /**
  * Class ChangeStatusCommandTest
  */
-class ChangeStatusCommandTest extends TestCase
+final class ChangeStatusCommandTest extends TestCase
 {
-    protected $command;
-    protected $userModel;
-    protected $commandName = 'admin:user:change-status';
+    private $command;
+
+    private $userModel;
 
-    public function setUp(): void
+    private $commandName = 'admin:user:change-status';
+
+    protected function setUp(): void
     {
         $this->command = $this->getMockBuilder(ChangeStatusCommand::class)
             ->setMethods(['getUserModel'])
@@ -35,7 +39,7 @@ public function testCanEnableByUser()
     {
         $username = 'aydin';
         $this->userModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('loadByUsername')
             ->with($username)
             ->willReturn($this->userModel);
@@ -51,7 +55,7 @@ public function testCanEnableByUser()
             ->willReturn(2);
 
         $this->userModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('validate');
 
         $this->userModel
@@ -60,12 +64,12 @@ public function testCanEnableByUser()
             ->willReturn(0);
 
         $this->userModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('setIsActive')
             ->with(1);
 
         $this->userModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('save');
 
         $this->userModel
@@ -74,12 +78,13 @@ public function testCanEnableByUser()
             ->willReturn(1);
 
         $this->userModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('getUsername')
             ->willReturn($username);
 
         $application = $this->getApplication();
         $application->add($this->command);
+
         $command = $this->getApplication()->find($this->commandName);
 
         $commandTester = new CommandTester($command);
@@ -87,14 +92,14 @@ public function testCanEnableByUser()
             ['command'   => $command->getName(), 'id'        => $username],
         );
 
-        self::assertStringContainsString("User $username is now active", $commandTester->getDisplay());
+        $this->assertStringContainsString(sprintf('User %s is now active', $username), $commandTester->getDisplay());
     }
 
     public function testCanDisableUser()
     {
         $username = 'aydin';
         $this->userModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('loadByUsername')
             ->with($username)
             ->willReturn($this->userModel);
@@ -110,7 +115,7 @@ public function testCanDisableUser()
             ->willReturn(2);
 
         $this->userModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('validate');
 
         $this->userModel
@@ -119,12 +124,12 @@ public function testCanDisableUser()
             ->willReturn(1);
 
         $this->userModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('setIsActive')
             ->with(0);
 
         $this->userModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('save');
 
         $this->userModel
@@ -133,12 +138,13 @@ public function testCanDisableUser()
             ->willReturn(2);
 
         $this->userModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('getUsername')
             ->willReturn($username);
 
         $application = $this->getApplication();
         $application->add($this->command);
+
         $command = $this->getApplication()->find($this->commandName);
 
         $commandTester = new CommandTester($command);
@@ -146,14 +152,14 @@ public function testCanDisableUser()
             ['command'   => $command->getName(), 'id'        => $username],
         );
 
-        self::assertStringContainsString("User $username is now inactive", $commandTester->getDisplay());
+        $this->assertStringContainsString(sprintf('User %s is now inactive', $username), $commandTester->getDisplay());
     }
 
     public function testCanToggleUserByEmail()
     {
         $username = 'aydin';
         $this->userModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('loadByUsername')
             ->with($username)
             ->willReturn($this->userModel);
@@ -164,7 +170,7 @@ public function testCanToggleUserByEmail()
             ->willReturn(0);
 
         $this->userModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('load')
             ->willReturn($this->userModel);
 
@@ -174,7 +180,7 @@ public function testCanToggleUserByEmail()
             ->willReturn(2);
 
         $this->userModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('validate');
 
         $this->userModel
@@ -183,12 +189,12 @@ public function testCanToggleUserByEmail()
             ->willReturn(0);
 
         $this->userModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('setIsActive')
             ->with(1);
 
         $this->userModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('save');
 
         $this->userModel
@@ -197,12 +203,13 @@ public function testCanToggleUserByEmail()
             ->willReturn(1);
 
         $this->userModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('getUsername')
             ->willReturn($username);
 
         $application = $this->getApplication();
         $application->add($this->command);
+
         $command = $this->getApplication()->find($this->commandName);
 
         $commandTester = new CommandTester($command);
@@ -210,13 +217,13 @@ public function testCanToggleUserByEmail()
             ['command'   => $command->getName(), 'id'        => $username],
         );
 
-        self::assertStringContainsString("User $username is now active", $commandTester->getDisplay());
+        $this->assertStringContainsString(sprintf('User %s is now active', $username), $commandTester->getDisplay());
     }
 
     public function testReturnEarlyIfUserNotFound()
     {
         $this->userModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('loadByUsername')
             ->with('notauser')
             ->willReturn($this->userModel);
@@ -227,7 +234,7 @@ public function testReturnEarlyIfUserNotFound()
             ->willReturn(null);
 
         $this->userModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('load')
             ->with('notauser', 'email')
             ->willReturn($this->userModel);
@@ -239,12 +246,13 @@ public function testReturnEarlyIfUserNotFound()
 
         $application = $this->getApplication();
         $application->add($this->command);
+
         $command = $this->getApplication()->find($this->commandName);
 
         $commandTester = new CommandTester($command);
         $commandTester->execute(['command'   => $command->getName(), 'id'        => 'notauser']);
 
-        self::assertStringContainsString('User was not found', $commandTester->getDisplay());
+        $this->assertStringContainsString('User was not found', $commandTester->getDisplay());
     }
 
     public function testIfNoIdIsPresentItIsPromptedFor()
@@ -255,12 +263,12 @@ public function testIfNoIdIsPresentItIsPromptedFor()
             ->setMethods(['ask'])
             ->getMock();
 
-        $dialog->expects(self::once())
+        $dialog->expects($this->once())
             ->method('ask')
             ->willReturn($userEmail);
 
         $this->userModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('loadByUsername')
             ->with($userEmail)
             ->willReturn($this->userModel);
@@ -275,6 +283,7 @@ public function testIfNoIdIsPresentItIsPromptedFor()
 
         $application = $this->getApplication();
         $application->add($this->command);
+
         $command = $this->getApplication()->find($this->commandName);
 
         // We override the standard helper with our mock
@@ -283,6 +292,6 @@ public function testIfNoIdIsPresentItIsPromptedFor()
         $commandTester = new CommandTester($command);
         $commandTester->execute(['command'   => $command->getName()]);
 
-        self::assertStringContainsString('User aydin is now inactive', $commandTester->getDisplay());
+        $this->assertStringContainsString('User aydin is now inactive', $commandTester->getDisplay());
     }
 }
diff --git a/tests/N98/Magento/Command/Admin/User/CreateUserCommandTest.php b/tests/N98/Magento/Command/Admin/User/CreateUserCommandTest.php
index 47c827b00..b3acde662 100644
--- a/tests/N98/Magento/Command/Admin/User/CreateUserCommandTest.php
+++ b/tests/N98/Magento/Command/Admin/User/CreateUserCommandTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\Admin\User;
 
 use Mage_Admin_Model_Roles;
@@ -12,15 +14,19 @@
 /**
  * Class CreateUserCommandTest
  */
-class CreateUserCommandTest extends TestCase
+final class CreateUserCommandTest extends TestCase
 {
-    protected $command;
-    protected $userModel;
-    protected $roleModel;
-    protected $rulesModel;
-    protected $commandName = 'admin:user:create';
+    private $command;
+
+    private $userModel;
+
+    private $roleModel;
+
+    private $rulesModel;
 
-    public function setUp(): void
+    private $commandName = 'admin:user:create';
+
+    protected function setUp(): void
     {
         $this->command = $this->getMockBuilder(CreateUserCommand::class)
             ->setMethods(['getUserModel', 'getRoleModel', 'getRulesModel'])
@@ -82,7 +88,7 @@ public function testArgumentPromptsWhenNotPresent()
             ->willReturn('Hassan');
 
         $this->roleModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('load')
             ->with('Administrators', 'role_name')
             ->willReturn($this->roleModel);
@@ -105,12 +111,12 @@ public function testArgumentPromptsWhenNotPresent()
             ->willReturn($this->userModel);
 
         $this->userModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('save')
             ->willReturn($this->userModel);
 
         $this->userModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('setRoleIds')
             ->with([9])
             ->willReturn($this->userModel);
@@ -121,17 +127,18 @@ public function testArgumentPromptsWhenNotPresent()
             ->willReturn(2);
 
         $this->userModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('setRoleUserId')
             ->with(2)
             ->willReturn($this->userModel);
 
         $this->userModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('saveRelations');
 
         $application = $this->getApplication();
         $application->add($this->command);
+
         $command = $this->getApplication()->find($this->commandName);
 
         // We override the standard helper with our mock
@@ -140,40 +147,42 @@ public function testArgumentPromptsWhenNotPresent()
         $commandTester = new CommandTester($command);
         $commandTester->execute(['command' => $command->getName(), 'role' => 'Administrators']);
 
-        self::assertStringContainsString('User aydin successfully created', $commandTester->getDisplay());
+        $this->assertStringContainsString('User aydin successfully created', $commandTester->getDisplay());
     }
 
     public function testInvalidRole()
     {
         $application = $this->getApplication();
         $application->add($this->command);
+
         $command = $this->getApplication()->find($this->commandName);
 
         $this->roleModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('load')
             ->with('invalid role', 'role_name')
             ->willReturn($this->roleModel);
 
         $this->roleModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('getId')
             ->willReturn(null);
 
         $commandTester = new CommandTester($command);
         $commandTester->execute(['command'   => $command->getName(), 'username'  => 'aydin', 'firstname' => 'Aydin', 'lastname'  => 'Hassan', 'email'     => 'aydin@hotmail.co.uk', 'password'  => 'p4ssw0rd', 'role'      => 'invalid role']);
 
-        self::assertStringContainsString('Role was not found', $commandTester->getDisplay());
+        $this->assertStringContainsString('Role was not found', $commandTester->getDisplay());
     }
 
     public function testCreatingDevelopmentRole()
     {
         $application = $this->getApplication();
         $application->add($this->command);
+
         $command = $this->getApplication()->find($this->commandName);
 
         $this->roleModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('load')
             ->with('Development', 'role_name')
             ->willReturn($this->roleModel);
@@ -184,19 +193,19 @@ public function testCreatingDevelopmentRole()
             ->willReturn(null);
 
         $this->roleModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('setName')
             ->with('Development')
             ->willReturn($this->roleModel);
 
         $this->roleModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('setRoleType')
             ->with('G')
             ->willReturn($this->roleModel);
 
         $this->roleModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('save');
 
         $this->roleModel
@@ -205,19 +214,19 @@ public function testCreatingDevelopmentRole()
             ->willReturn(5);
 
         $this->rulesModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('setRoleId')
             ->with(5)
             ->willReturn($this->rulesModel);
 
         $this->rulesModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('setResources')
             ->with(['all'])
             ->willReturn($this->rulesModel);
 
         $this->rulesModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('saveRel');
 
         $this->userModel
@@ -234,7 +243,7 @@ public function testCreatingDevelopmentRole()
             ->willReturn($this->userModel);
 
         $this->userModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('save')
             ->willReturn($this->userModel);
 
@@ -244,7 +253,7 @@ public function testCreatingDevelopmentRole()
             ->willReturn(5);
 
         $this->userModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('setRoleIds')
             ->with([5])
             ->willReturn($this->userModel);
@@ -255,13 +264,13 @@ public function testCreatingDevelopmentRole()
             ->willReturn(2);
 
         $this->userModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('setRoleUserId')
             ->with(2)
             ->willReturn($this->userModel);
 
         $this->userModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('saveRelations');
 
         $commandTester = new CommandTester($command);
@@ -274,7 +283,7 @@ public function testCreatingDevelopmentRole()
             'password'  => 'p4ssw0rd',
         ]);
 
-        self::assertStringContainsString('The role Development was automatically created', $commandTester->getDisplay());
-        self::assertStringContainsString('User aydin successfully created', $commandTester->getDisplay());
+        $this->assertStringContainsString('The role Development was automatically created', $commandTester->getDisplay());
+        $this->assertStringContainsString('User aydin successfully created', $commandTester->getDisplay());
     }
 }
diff --git a/tests/N98/Magento/Command/Admin/User/DeleteUserCommandTest.php b/tests/N98/Magento/Command/Admin/User/DeleteUserCommandTest.php
index 0006fbf03..d8a233d84 100644
--- a/tests/N98/Magento/Command/Admin/User/DeleteUserCommandTest.php
+++ b/tests/N98/Magento/Command/Admin/User/DeleteUserCommandTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\Admin\User;
 
 use Exception;
@@ -10,12 +12,13 @@
 /**
  * Class DeleteUserCommandTest
  */
-class DeleteUserCommandTest extends TestCase
+final class DeleteUserCommandTest extends TestCase
 {
-    protected $command;
-    protected $userModel;
+    private $command;
+
+    private $userModel;
 
-    public function setUp(): void
+    protected function setUp(): void
     {
         $this->command = $this->getMockBuilder(DeleteUserCommand::class)
             ->setMethods(['getUserModel'])
@@ -34,7 +37,7 @@ public function setUp(): void
     public function testCanDeleteByUserName()
     {
         $this->userModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('loadByUsername')
             ->with('aydin')
             ->willReturn($this->userModel);
@@ -50,15 +53,16 @@ public function testCanDeleteByUserName()
             ->willReturn(2);
 
         $this->userModel
-            ->expects(self::never())
+            ->expects($this->never())
             ->method('load');
 
         $this->userModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('delete');
 
         $application = $this->getApplication();
         $application->add($this->command);
+
         $command = $this->getApplication()->find('admin:user:delete');
 
         $commandTester = new CommandTester($command);
@@ -66,13 +70,13 @@ public function testCanDeleteByUserName()
             ['command'   => $command->getName(), 'id'        => 'aydin', '--force'   => true],
         );
 
-        self::assertStringContainsString('User was successfully deleted', $commandTester->getDisplay());
+        $this->assertStringContainsString('User was successfully deleted', $commandTester->getDisplay());
     }
 
     public function testCanDeleteByEmail()
     {
         $this->userModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('loadByUsername')
             ->with('aydin@hotmail.co.uk')
             ->willReturn($this->userModel);
@@ -83,7 +87,7 @@ public function testCanDeleteByEmail()
             ->willReturn(null);
 
         $this->userModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('load')
             ->with('aydin@hotmail.co.uk', 'email')
             ->willReturn($this->userModel);
@@ -94,11 +98,12 @@ public function testCanDeleteByEmail()
             ->willReturn(2);
 
         $this->userModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('delete');
 
         $application = $this->getApplication();
         $application->add($this->command);
+
         $command = $this->getApplication()->find('admin:user:delete');
 
         $commandTester = new CommandTester($command);
@@ -106,13 +111,13 @@ public function testCanDeleteByEmail()
             ['command'   => $command->getName(), 'id'        => 'aydin@hotmail.co.uk', '--force'   => true],
         );
 
-        self::assertStringContainsString('User was successfully deleted', $commandTester->getDisplay());
+        $this->assertStringContainsString('User was successfully deleted', $commandTester->getDisplay());
     }
 
     public function testReturnEarlyIfUserNotFound()
     {
         $this->userModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('loadByUsername')
             ->with('notauser')
             ->willReturn($this->userModel);
@@ -123,7 +128,7 @@ public function testReturnEarlyIfUserNotFound()
             ->willReturn(null);
 
         $this->userModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('load')
             ->with('notauser', 'email')
             ->willReturn($this->userModel);
@@ -135,18 +140,19 @@ public function testReturnEarlyIfUserNotFound()
 
         $application = $this->getApplication();
         $application->add($this->command);
+
         $command = $this->getApplication()->find('admin:user:delete');
 
         $commandTester = new CommandTester($command);
         $commandTester->execute(['command'   => $command->getName(), 'id'        => 'notauser']);
 
-        self::assertStringContainsString('User was not found', $commandTester->getDisplay());
+        $this->assertStringContainsString('User was not found', $commandTester->getDisplay());
     }
 
     public function testMessageIsPrintedIfErrorDeleting()
     {
         $this->userModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('loadByUsername')
             ->with('aydin@hotmail.co.uk')
             ->willReturn($this->userModel);
@@ -157,7 +163,7 @@ public function testMessageIsPrintedIfErrorDeleting()
             ->willReturn(null);
 
         $this->userModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('load')
             ->with('aydin@hotmail.co.uk', 'email')
             ->willReturn($this->userModel);
@@ -169,12 +175,13 @@ public function testMessageIsPrintedIfErrorDeleting()
 
         $exception = new Exception('Error!');
         $this->userModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('delete')
-            ->will(self::throwException($exception));
+            ->willThrowException($exception);
 
         $application = $this->getApplication();
         $application->add($this->command);
+
         $command = $this->getApplication()->find('admin:user:delete');
 
         $commandTester = new CommandTester($command);
@@ -182,13 +189,13 @@ public function testMessageIsPrintedIfErrorDeleting()
             ['command'   => $command->getName(), 'id'        => 'aydin@hotmail.co.uk', '--force'   => true],
         );
 
-        self::assertStringContainsString('Error!', $commandTester->getDisplay());
+        $this->assertStringContainsString('Error!', $commandTester->getDisplay());
     }
 
     public function testConfirmationTrueReplyDeletesUser()
     {
         $this->userModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('loadByUsername')
             ->with('notauser')
             ->willReturn($this->userModel);
@@ -199,7 +206,7 @@ public function testConfirmationTrueReplyDeletesUser()
             ->willReturn(null);
 
         $this->userModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('load')
             ->with('notauser', 'email')
             ->willReturn($this->userModel);
@@ -210,18 +217,19 @@ public function testConfirmationTrueReplyDeletesUser()
             ->willReturn(2);
 
         $this->userModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('delete');
 
         $application = $this->getApplication();
         $application->add($this->command);
+
         $command = $this->getApplication()->find('admin:user:delete');
 
         $questionHelper = $this->getMockBuilder(QuestionHelper::class)
             ->onlyMethods(['ask'])
             ->getMock();
 
-        $questionHelper->expects(self::once())
+        $questionHelper->expects($this->once())
             ->method('ask')
             ->willReturn(true);
 
@@ -231,13 +239,13 @@ public function testConfirmationTrueReplyDeletesUser()
         $commandTester = new CommandTester($command);
         $commandTester->execute(['command'   => $command->getName(), 'id'        => 'notauser']);
 
-        self::assertStringContainsString('User was successfully deleted', $commandTester->getDisplay());
+        $this->assertStringContainsString('User was successfully deleted', $commandTester->getDisplay());
     }
 
     public function testConfirmationFalseReplyDoesNotDeleteUser()
     {
         $this->userModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('loadByUsername')
             ->with('notauser')
             ->willReturn($this->userModel);
@@ -248,7 +256,7 @@ public function testConfirmationFalseReplyDoesNotDeleteUser()
             ->willReturn(null);
 
         $this->userModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('load')
             ->with('notauser', 'email')
             ->willReturn($this->userModel);
@@ -259,18 +267,19 @@ public function testConfirmationFalseReplyDoesNotDeleteUser()
             ->willReturn(2);
 
         $this->userModel
-            ->expects(self::never())
+            ->expects($this->never())
             ->method('delete');
 
         $application = $this->getApplication();
         $application->add($this->command);
+
         $command = $this->getApplication()->find('admin:user:delete');
 
         $questionHelper = $this->getMockBuilder(QuestionHelper::class)
             ->onlyMethods(['ask'])
             ->getMock();
 
-        $questionHelper->expects(self::once())
+        $questionHelper->expects($this->once())
             ->method('ask')
             ->willReturn(false);
 
@@ -283,7 +292,7 @@ public function testConfirmationFalseReplyDoesNotDeleteUser()
             'id'        => 'notauser',
         ]);
 
-        self::assertStringContainsString('Aborting delete', $commandTester->getDisplay());
+        $this->assertStringContainsString('Aborting delete', $commandTester->getDisplay());
     }
 
     public function testIfNoIdIsPresentItIsPromptedFor()
@@ -292,12 +301,12 @@ public function testIfNoIdIsPresentItIsPromptedFor()
             ->onlyMethods(['ask'])
             ->getMock();
 
-        $questionHelper->expects(self::once())
+        $questionHelper->expects($this->once())
             ->method('ask')
             ->willReturn('aydin@hotmail.co.uk');
 
         $this->userModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('loadByUsername')
             ->with('aydin@hotmail.co.uk')
             ->willReturn($this->userModel);
@@ -308,7 +317,7 @@ public function testIfNoIdIsPresentItIsPromptedFor()
             ->willReturn(null);
 
         $this->userModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('load')
             ->with('aydin@hotmail.co.uk', 'email')
             ->willReturn($this->userModel);
@@ -319,11 +328,12 @@ public function testIfNoIdIsPresentItIsPromptedFor()
             ->willReturn(2);
 
         $this->userModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('delete');
 
         $application = $this->getApplication();
         $application->add($this->command);
+
         $command = $this->getApplication()->find('admin:user:delete');
 
         // We override the standard helper with our mock
@@ -332,6 +342,6 @@ public function testIfNoIdIsPresentItIsPromptedFor()
         $commandTester = new CommandTester($command);
         $commandTester->execute(['command'   => $command->getName(), '--force'   => true]);
 
-        self::assertStringContainsString('User was successfully deleted', $commandTester->getDisplay());
+        $this->assertStringContainsString('User was successfully deleted', $commandTester->getDisplay());
     }
 }
diff --git a/tests/N98/Magento/Command/Admin/User/ListCommandTest.php b/tests/N98/Magento/Command/Admin/User/ListCommandTest.php
index 79562cb00..22e2bd482 100644
--- a/tests/N98/Magento/Command/Admin/User/ListCommandTest.php
+++ b/tests/N98/Magento/Command/Admin/User/ListCommandTest.php
@@ -1,24 +1,27 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\Admin\User;
 
 use N98\Magento\Command\TestCase;
 use Symfony\Component\Console\Tester\CommandTester;
 
-class ListCommandTest extends TestCase
+final class ListCommandTest extends TestCase
 {
     public function testExecute()
     {
         $application = $this->getApplication();
         $application->add(new ListCommand());
+
         $command = $this->getApplication()->find('admin:user:list');
 
         $commandTester = new CommandTester($command);
         $commandTester->execute(['command' => $command->getName()]);
 
-        self::assertStringContainsString('id', $commandTester->getDisplay());
-        self::assertStringContainsString('user', $commandTester->getDisplay());
-        self::assertStringContainsString('email', $commandTester->getDisplay());
-        self::assertStringContainsString('status', $commandTester->getDisplay());
+        $this->assertStringContainsString('id', $commandTester->getDisplay());
+        $this->assertStringContainsString('user', $commandTester->getDisplay());
+        $this->assertStringContainsString('email', $commandTester->getDisplay());
+        $this->assertStringContainsString('status', $commandTester->getDisplay());
     }
 }
diff --git a/tests/N98/Magento/Command/Cache/CleanCommandTest.php b/tests/N98/Magento/Command/Cache/CleanCommandTest.php
index ec131b0f6..9b2a31dc6 100644
--- a/tests/N98/Magento/Command/Cache/CleanCommandTest.php
+++ b/tests/N98/Magento/Command/Cache/CleanCommandTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\Cache;
 
 use RuntimeException;
@@ -9,7 +11,7 @@
 use N98\Magento\Command\TestCase;
 use Symfony\Component\Console\Tester\CommandTester;
 
-class CleanCommandTest extends TestCase
+final class CleanCommandTest extends TestCase
 {
     /**
      * @throws RuntimeException
@@ -25,6 +27,7 @@ public function getApplication()
         if ($application->isMagentoEnterprise()) {
             $against = '1.14.0.0';
         }
+
         if (-1 != version_compare($version, $against)) {
             self::markTestSkipped(
                 sprintf(
@@ -42,18 +45,20 @@ public function testExecute()
     {
         $application = $this->getApplication();
         $application->add(new CleanCommand());
+
         $command = $this->getApplication()->find('cache:clean');
 
         $commandTester = new CommandTester($command);
         $commandTester->execute(['command' => $command->getName()]);
 
-        self::assertStringContainsString('Cache config cleaned', $commandTester->getDisplay());
+        $this->assertStringContainsString('Cache config cleaned', $commandTester->getDisplay());
     }
 
     public function testItCanCleanMultipleCaches()
     {
         $application = $this->getApplication();
         $application->add(new CleanCommand());
+
         $command = $this->getApplication()->find('cache:clean');
 
         $commandTester = new CommandTester($command);
@@ -61,7 +66,7 @@ public function testItCanCleanMultipleCaches()
 
         $display = $commandTester->getDisplay();
 
-        self::assertStringContainsString('Cache config cleaned', $display);
-        self::assertStringContainsString('Cache layout cleaned', $display);
+        $this->assertStringContainsString('Cache config cleaned', $display);
+        $this->assertStringContainsString('Cache layout cleaned', $display);
     }
 }
diff --git a/tests/N98/Magento/Command/Cache/Dir/FlushCommandTest.php b/tests/N98/Magento/Command/Cache/Dir/FlushCommandTest.php
index c83e28359..0c49de88e 100644
--- a/tests/N98/Magento/Command/Cache/Dir/FlushCommandTest.php
+++ b/tests/N98/Magento/Command/Cache/Dir/FlushCommandTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 /**
  * this file is part of magerun
  *
@@ -17,7 +19,7 @@
  *
  * @package N98\Magento\Command\Cache
  */
-class FlushCommandTest extends TestCase
+final class FlushCommandTest extends TestCase
 {
     public function testExecute()
     {
@@ -26,8 +28,8 @@ public function testExecute()
         $commandTester->execute(['command' => $command->getName()]);
 
         $display = $commandTester->getDisplay();
-        self::assertStringContainsString('Flushing cache directory ', $display);
-        self::assertStringContainsString('Cache directory flushed', $display);
+        $this->assertStringContainsString('Flushing cache directory ', $display);
+        $this->assertStringContainsString('Cache directory flushed', $display);
     }
 
     /**
@@ -39,8 +41,7 @@ private function prepareCommand($object)
     {
         $application = $this->getApplication();
         $application->add($object);
-        $command = $application->find($object::NAME);
 
-        return $command;
+        return $application->find($object::NAME);
     }
 }
diff --git a/tests/N98/Magento/Command/Cache/DisableCommandTest.php b/tests/N98/Magento/Command/Cache/DisableCommandTest.php
index f27249ddb..fb683a745 100644
--- a/tests/N98/Magento/Command/Cache/DisableCommandTest.php
+++ b/tests/N98/Magento/Command/Cache/DisableCommandTest.php
@@ -1,12 +1,14 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\Cache;
 
 use N98\Magento\Application;
 use N98\Magento\Command\TestCase;
 use Symfony\Component\Console\Tester\CommandTester;
 
-class DisableCommandTest extends TestCase
+final class DisableCommandTest extends TestCase
 {
     public function testExecute()
     {
@@ -17,7 +19,7 @@ public function testExecute()
         $commandTester = new CommandTester($command);
         $commandTester->execute(['command' => $command->getName()]);
 
-        self::assertMatchesRegularExpression('/Caches disabled/', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression('/Caches disabled/', $commandTester->getDisplay());
     }
 
     public function testExecuteMultipleCaches()
@@ -31,7 +33,7 @@ public function testExecuteMultipleCaches()
             ['command' => $command->getName(), 'code'    => 'eav,config'],
         );
 
-        self::assertMatchesRegularExpression('/Cache config disabled/', $commandTester->getDisplay());
-        self::assertMatchesRegularExpression('/Cache eav disabled/', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression('/Cache config disabled/', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression('/Cache eav disabled/', $commandTester->getDisplay());
     }
 }
diff --git a/tests/N98/Magento/Command/Cache/EnableCommandTest.php b/tests/N98/Magento/Command/Cache/EnableCommandTest.php
index a8f53f060..23e40f51a 100644
--- a/tests/N98/Magento/Command/Cache/EnableCommandTest.php
+++ b/tests/N98/Magento/Command/Cache/EnableCommandTest.php
@@ -1,23 +1,26 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\Cache;
 
 use N98\Magento\Application;
 use N98\Magento\Command\TestCase;
 use Symfony\Component\Console\Tester\CommandTester;
 
-class EnableCommandTest extends TestCase
+final class EnableCommandTest extends TestCase
 {
     public function testExecute()
     {
         $application = $this->getApplication();
         $application->add(new EnableCommand());
+
         $command = $this->getApplication()->find('cache:enable');
 
         $commandTester = new CommandTester($command);
         $commandTester->execute(['command' => $command->getName()]);
 
-        self::assertMatchesRegularExpression('/Caches enabled/', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression('/Caches enabled/', $commandTester->getDisplay());
     }
 
     public function testExecuteMultipleCaches()
@@ -31,7 +34,7 @@ public function testExecuteMultipleCaches()
             ['command' => $command->getName(), 'code'    => 'eav,config'],
         );
 
-        self::assertMatchesRegularExpression('/Cache config enabled/', $commandTester->getDisplay());
-        self::assertMatchesRegularExpression('/Cache eav enabled/', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression('/Cache config enabled/', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression('/Cache eav enabled/', $commandTester->getDisplay());
     }
 }
diff --git a/tests/N98/Magento/Command/Cache/FlushCommandTest.php b/tests/N98/Magento/Command/Cache/FlushCommandTest.php
index 236c518c1..6264fd509 100644
--- a/tests/N98/Magento/Command/Cache/FlushCommandTest.php
+++ b/tests/N98/Magento/Command/Cache/FlushCommandTest.php
@@ -1,22 +1,25 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\Cache;
 
 use N98\Magento\Application;
 use N98\Magento\Command\TestCase;
 use Symfony\Component\Console\Tester\CommandTester;
 
-class FlushCommandTest extends TestCase
+final class FlushCommandTest extends TestCase
 {
     public function testExecute()
     {
         $application = $this->getApplication();
         $application->add(new FlushCommand());
+
         $command = $this->getApplication()->find('cache:flush');
 
         $commandTester = new CommandTester($command);
         $commandTester->execute(['command' => $command->getName()]);
 
-        self::assertMatchesRegularExpression('/Cache cleared/', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression('/Cache cleared/', $commandTester->getDisplay());
     }
 }
diff --git a/tests/N98/Magento/Command/Cache/ListCommandTest.php b/tests/N98/Magento/Command/Cache/ListCommandTest.php
index f636a6f27..e3f4c0052 100644
--- a/tests/N98/Magento/Command/Cache/ListCommandTest.php
+++ b/tests/N98/Magento/Command/Cache/ListCommandTest.php
@@ -1,22 +1,25 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\Cache;
 
 use N98\Magento\Command\TestCase;
 use Symfony\Component\Console\Tester\CommandTester;
 
-class ListCommandTest extends TestCase
+final class ListCommandTest extends TestCase
 {
     public function testExecute()
     {
         $application = $this->getApplication();
         $application->add(new ListCommand());
+
         $command = $this->getApplication()->find('cache:list');
 
         $commandTester = new CommandTester($command);
         $commandTester->execute(['command' => $command->getName()]);
 
-        self::assertMatchesRegularExpression('/config/', $commandTester->getDisplay());
-        self::assertMatchesRegularExpression('/collections/', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression('/config/', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression('/collections/', $commandTester->getDisplay());
     }
 }
diff --git a/tests/N98/Magento/Command/Cache/ReportCommandTest.php b/tests/N98/Magento/Command/Cache/ReportCommandTest.php
index a315725fe..1c0630f95 100644
--- a/tests/N98/Magento/Command/Cache/ReportCommandTest.php
+++ b/tests/N98/Magento/Command/Cache/ReportCommandTest.php
@@ -1,16 +1,19 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\Cache;
 
 use N98\Magento\Command\TestCase;
 use Symfony\Component\Console\Tester\CommandTester;
 
-class ReportCommandTest extends TestCase
+final class ReportCommandTest extends TestCase
 {
     public function testExecute()
     {
         $application = $this->getApplication();
         $application->add(new ListCommand());
+
         $command = $this->getApplication()->find('cache:report');
 
         $commandTester = new CommandTester($command);
@@ -18,9 +21,9 @@ public function testExecute()
             ['command' => $command->getName(), '--tags'  => true, '--mtime' => true],
         );
 
-        self::assertMatchesRegularExpression('/ID/', $commandTester->getDisplay());
-        self::assertMatchesRegularExpression('/EXPIRE/', $commandTester->getDisplay());
-        self::assertMatchesRegularExpression('/MTIME/', $commandTester->getDisplay());
-        self::assertMatchesRegularExpression('/TAGS/', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression('/ID/', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression('/EXPIRE/', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression('/MTIME/', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression('/TAGS/', $commandTester->getDisplay());
     }
 }
diff --git a/tests/N98/Magento/Command/Cache/ViewCommandTest.php b/tests/N98/Magento/Command/Cache/ViewCommandTest.php
index be5379793..9e5df04b9 100644
--- a/tests/N98/Magento/Command/Cache/ViewCommandTest.php
+++ b/tests/N98/Magento/Command/Cache/ViewCommandTest.php
@@ -1,17 +1,20 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\Cache;
 
 use Mage;
 use N98\Magento\Command\TestCase;
 use Symfony\Component\Console\Tester\CommandTester;
 
-class ViewCommandTest extends TestCase
+final class ViewCommandTest extends TestCase
 {
     public function testExecute()
     {
         $application = $this->getApplication();
         $application->add(new ListCommand());
+
         $command = $this->getApplication()->find('cache:view');
 
         Mage::app()->getCache()->save('TEST n98-magerun', 'n98-magerun-unittest');
@@ -21,13 +24,14 @@ public function testExecute()
             ['command' => $command->getName(), 'id'      => 'n98-magerun-unittest'],
         );
 
-        self::assertMatchesRegularExpression('/TEST n98-magerun/', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression('/TEST n98-magerun/', $commandTester->getDisplay());
     }
 
     public function testExecuteUnserialize()
     {
         $application = $this->getApplication();
         $application->add(new ListCommand());
+
         $command = $this->getApplication()->find('cache:view');
 
         $cacheData = [1, 2, 3, 'foo' => ['bar']];
@@ -38,6 +42,6 @@ public function testExecuteUnserialize()
             ['command'       => $command->getName(), 'id'            => 'n98-magerun-unittest', '--unserialize' => true],
         );
 
-        self::assertEquals(print_r($cacheData, true) . "\n", $commandTester->getDisplay(true));
+        $this->assertSame(print_r($cacheData, true) . "\n", $commandTester->getDisplay(true));
     }
 }
diff --git a/tests/N98/Magento/Command/Category/Create/DummyCommandTest.php b/tests/N98/Magento/Command/Category/Create/DummyCommandTest.php
index 127095b66..840fd21ad 100644
--- a/tests/N98/Magento/Command/Category/Create/DummyCommandTest.php
+++ b/tests/N98/Magento/Command/Category/Create/DummyCommandTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\Category\Create;
 
 use Mage;
@@ -10,12 +12,13 @@
 use N98\Magento\Command\TestCase;
 use Symfony\Component\Console\Tester\CommandTester;
 
-class DummyCommandTest extends TestCase
+final class DummyCommandTest extends TestCase
 {
     public function testExecute()
     {
         $application = $this->getApplication();
         $application->add(new DummyCommand());
+
         $command = $application->find('category:create:dummy');
         $commandTester = new CommandTester($command);
 
@@ -23,30 +26,32 @@ public function testExecute()
             ['command'                    => $command->getName(), 'store-id'                   => 1, 'children-categories-number' => 1, 'category-name-prefix'       => 'My Awesome Category', 'category-number'            => 1],
         );
 
-        self::assertMatchesRegularExpression('/CATEGORY: \'My Awesome Category (.+)\' WITH ID: \'(.+)\' CREATED!/', $commandTester->getDisplay());
-        self::assertMatchesRegularExpression('/CATEGORY CHILD: \'My Awesome Category (.+)\' WITH ID: \'(.+)\' CREATED!/', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression("/CATEGORY: 'My Awesome Category (.+)' WITH ID: '(.+)' CREATED!/", $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression("/CATEGORY CHILD: 'My Awesome Category (.+)' WITH ID: '(.+)' CREATED!/", $commandTester->getDisplay());
 
         // Check if the category is created correctly
         $match_parent = '';
         $match_child = '';
-        preg_match('/CATEGORY: \'My Awesome Category (.+)\' WITH ID: \'(.+)\' CREATED!/', $commandTester->getDisplay(), $match_parent);
-        self::assertTrue($this->checkifCategoryExist($match_parent[2]));
-        preg_match('/CATEGORY CHILD: \'My Awesome Category (.+)\' WITH ID: \'(.+)\' CREATED!/', $commandTester->getDisplay(), $match_child);
-        self::assertTrue($this->checkifCategoryExist($match_child[2]));
+        preg_match("/CATEGORY: 'My Awesome Category (.+)' WITH ID: '(.+)' CREATED!/", $commandTester->getDisplay(), $match_parent);
+        $this->assertTrue($this->checkifCategoryExist($match_parent[2]));
+        preg_match("/CATEGORY CHILD: 'My Awesome Category (.+)' WITH ID: '(.+)' CREATED!/", $commandTester->getDisplay(), $match_child);
+        $this->assertTrue($this->checkifCategoryExist($match_child[2]));
 
         // Delete category created
         $this->deleteMagentoCategory($match_parent[2]);
         $this->deleteMagentoCategory($match_child[2]);
     }
 
-    protected function checkifCategoryExist($_category_id)
+    private function checkifCategoryExist($_category_id)
     {
         if (!is_null(Mage::getModel('catalog/category')->load($_category_id)->getName())) {
             return true;
         }
+
+        return null;
     }
 
-    protected function deleteMagentoCategory($_category_id)
+    private function deleteMagentoCategory($_category_id)
     {
         Mage::getModel('catalog/category')->load($_category_id)->delete();
     }
@@ -55,6 +60,7 @@ public function testmanageArguments()
     {
         $application = $this->getApplication();
         $application->add(new DummyCommand());
+
         $command = $application->find('category:create:dummy');
 
         $dialog = $this->getMockBuilder(QuestionHelper::class)
@@ -114,9 +120,9 @@ public function testmanageArguments()
         );
 
         $arguments = $commandTester->getInput()->getArguments();
-        self::assertArrayHasKey('store-id', $arguments);
-        self::assertArrayHasKey('children-categories-number', $arguments);
-        self::assertArrayHasKey('category-name-prefix', $arguments);
-        self::assertArrayHasKey('category-number', $arguments);
+        $this->assertArrayHasKey('store-id', $arguments);
+        $this->assertArrayHasKey('children-categories-number', $arguments);
+        $this->assertArrayHasKey('category-name-prefix', $arguments);
+        $this->assertArrayHasKey('category-number', $arguments);
     }
 }
diff --git a/tests/N98/Magento/Command/Cms/Block/ToggleCommandTest.php b/tests/N98/Magento/Command/Cms/Block/ToggleCommandTest.php
index b6ff684f6..508e7ffc6 100644
--- a/tests/N98/Magento/Command/Cms/Block/ToggleCommandTest.php
+++ b/tests/N98/Magento/Command/Cms/Block/ToggleCommandTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\Cms\Block;
 
 use Mage;
@@ -11,12 +13,13 @@
  *
  * @package N98\Magento\Command\Cms\Block
  */
-class ToggleCommandTest extends TestCase
+final class ToggleCommandTest extends TestCase
 {
     public function testExecute()
     {
         $application = $this->getApplication();
         $application->add(new ToggleCommand());
+
         $command = $this->getApplication()->find('cms:block:toggle');
         $commandTester = new CommandTester($command);
         $victim = Mage::getModel('cms/block')->getCollection()->getFirstItem();
@@ -27,7 +30,7 @@ public function testExecute()
                 'block_id' => $victim->getId(),
             ],
         );
-        self::assertStringContainsString('disabled', $commandTester->getDisplay());
+        $this->assertStringContainsString('disabled', $commandTester->getDisplay());
         $commandTester->execute(
             [
                 'command'  => $command->getName(),
@@ -35,6 +38,6 @@ public function testExecute()
                 'block_id' => $victim->getIdentifier(),
             ],
         );
-        self::assertStringContainsString('enabled', $commandTester->getDisplay());
+        $this->assertStringContainsString('enabled', $commandTester->getDisplay());
     }
 }
diff --git a/tests/N98/Magento/Command/Config/DeleteCommandTest.php b/tests/N98/Magento/Command/Config/DeleteCommandTest.php
index 817359305..6b8060938 100644
--- a/tests/N98/Magento/Command/Config/DeleteCommandTest.php
+++ b/tests/N98/Magento/Command/Config/DeleteCommandTest.php
@@ -1,17 +1,20 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\Config;
 
 use Mage;
 use N98\Magento\Command\TestCase;
 use Symfony\Component\Console\Tester\CommandTester;
 
-class DeleteCommandTest extends TestCase
+final class DeleteCommandTest extends TestCase
 {
     public function testExecute()
     {
         $application = $this->getApplication();
         $application->add(new DumpCommand());
+
         $setCommand = $this->getApplication()->find('config:set');
         $deleteCommand = $this->getApplication()->find('config:delete');
 
@@ -22,13 +25,13 @@ public function testExecute()
         $commandTester->execute(
             ['command' => $setCommand->getName(), 'path'    => 'n98_magerun/foo/bar', 'value'   => '1234'],
         );
-        self::assertStringContainsString('n98_magerun/foo/bar => 1234', $commandTester->getDisplay());
+        $this->assertStringContainsString('n98_magerun/foo/bar => 1234', $commandTester->getDisplay());
 
         $commandTester = new CommandTester($deleteCommand);
         $commandTester->execute(
             ['command' => $deleteCommand->getName(), 'path'    => 'n98_magerun/foo/bar'],
         );
-        self::assertStringContainsString('| n98_magerun/foo/bar | default | 0        |', $commandTester->getDisplay());
+        $this->assertStringContainsString('| n98_magerun/foo/bar | default | 0        |', $commandTester->getDisplay());
 
         /**
          * Delete all
@@ -53,7 +56,7 @@ public function testExecute()
         );
 
         foreach (Mage::app()->getStores() as $store) {
-            self::assertStringContainsString('| n98_magerun/foo/bar | stores   | ' . $store->getId() . '        |', $commandTester->getDisplay());
+            $this->assertStringContainsString('| n98_magerun/foo/bar | stores   | ' . $store->getId() . '        |', $commandTester->getDisplay());
         }
     }
 }
diff --git a/tests/N98/Magento/Command/Config/DumpCommandTest.php b/tests/N98/Magento/Command/Config/DumpCommandTest.php
index 669c9dd96..4c9726b5e 100644
--- a/tests/N98/Magento/Command/Config/DumpCommandTest.php
+++ b/tests/N98/Magento/Command/Config/DumpCommandTest.php
@@ -1,22 +1,25 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\Config;
 
 use N98\Magento\Command\TestCase;
 use Symfony\Component\Console\Tester\CommandTester;
 
-class DumpCommandTest extends TestCase
+final class DumpCommandTest extends TestCase
 {
     public function testExecute()
     {
         $application = $this->getApplication();
         $application->add(new DumpCommand());
+
         $command = $this->getApplication()->find('config:dump');
 
         $commandTester = new CommandTester($command);
         $commandTester->execute(
             ['command'   => $command->getName(), 'xpath'     => 'global/install'],
         );
-        self::assertStringContainsString('date', $commandTester->getDisplay());
+        $this->assertStringContainsString('date', $commandTester->getDisplay());
     }
 }
diff --git a/tests/N98/Magento/Command/Config/GetCommandTest.php b/tests/N98/Magento/Command/Config/GetCommandTest.php
index 4797236a4..e05d2920e 100644
--- a/tests/N98/Magento/Command/Config/GetCommandTest.php
+++ b/tests/N98/Magento/Command/Config/GetCommandTest.php
@@ -1,16 +1,15 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\Config;
 
 use Mage;
 use N98\Magento\Command\TestCase;
 
-class GetCommandTest extends TestCase
+final class GetCommandTest extends TestCase
 {
-    /**
-     * @test
-     */
-    public function nullValues()
+    public function testNullValues()
     {
         # Very old Magento versions do not support NULL values in configuration values
         $this->skipMagentoMinimumVersion('1.6.2.0', '1.11.2.0');
@@ -42,20 +41,22 @@ public function nullValues()
                 # needed to not use the previous output cache
                 'path'             => 'n98_magerun/foo/bar',
             ],
-            'config:set --scope-id=0 --scope=default -- \'n98_magerun/foo/bar\' NULL',
+            "config:set --scope-id=0 --scope=default -- 'n98_magerun/foo/bar' NULL",
         );
     }
 
-    public function provideFormatsWithNull()
+    public function provideFormatsWithNull(): \Iterator
     {
-        return [[null, '~\\Q| n98_magerun/foo/bar | default | 0        | NULL (NULL/"unknown" value) |\\E~'], ['csv', '~\\Qn98_magerun/foo/bar,default,0,NULL\\E~'], ['json', '~"Value": *null~'], ['xml', '~\\Q<Value>NULL</Value>\\E~']];
+        yield [null, '~\\Q| n98_magerun/foo/bar | default | 0        | NULL (NULL/"unknown" value) |\\E~'];
+        yield ['csv', '~\\Qn98_magerun/foo/bar,default,0,NULL\\E~'];
+        yield ['json', '~"Value": *null~'];
+        yield ['xml', '~\\Q<Value>NULL</Value>\\E~'];
     }
 
     /**
-     * @test
      * @dataProvider provideFormatsWithNull
      */
-    public function nullWithFormat($format, $expected)
+    public function testNullWithFormat($format, $expected)
     {
         # Very old Magento versions do not support NULL values in configuration values
         $this->skipMagentoMinimumVersion('1.6.2.0', '1.11.2.0');
@@ -150,6 +151,7 @@ private function skipMagentoMinimumVersion($community, $enterprise)
                         ),
                     );
                 }
+
                 break;
             case 'Enterprise':
                 if (version_compare($magentoVersion, $enterprise, '<')) {
@@ -161,6 +163,7 @@ private function skipMagentoMinimumVersion($community, $enterprise)
                         ),
                     );
                 }
+
                 break;
             default:
                 self::markTestSkipped(
diff --git a/tests/N98/Magento/Command/Config/SearchCommandTest.php b/tests/N98/Magento/Command/Config/SearchCommandTest.php
index ae3b5e4f5..e4d8cc393 100644
--- a/tests/N98/Magento/Command/Config/SearchCommandTest.php
+++ b/tests/N98/Magento/Command/Config/SearchCommandTest.php
@@ -1,28 +1,31 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\Config;
 
 use N98\Magento\Command\TestCase;
 use Symfony\Component\Console\Tester\CommandTester;
 
-class SearchCommandTest extends TestCase
+final class SearchCommandTest extends TestCase
 {
     public function testExecute()
     {
         $application = $this->getApplication();
         $application->add(new DumpCommand());
+
         $command = $this->getApplication()->find('config:search');
 
         $commandTester = new CommandTester($command);
         $commandTester->execute(
             ['command'   => $command->getName(), 'text'      => 'This message will be shown'],
         );
-        self::assertStringContainsString('Found a field with a match', $commandTester->getDisplay());
+        $this->assertStringContainsString('Found a field with a match', $commandTester->getDisplay());
 
         $commandTester = new CommandTester($command);
         $commandTester->execute(
             ['command'   => $command->getName(), 'text'      => 'xyz1234567890'],
         );
-        self::assertStringContainsString('No matches for xyz1234567890', $commandTester->getDisplay());
+        $this->assertStringContainsString('No matches for xyz1234567890', $commandTester->getDisplay());
     }
 }
diff --git a/tests/N98/Magento/Command/Customer/CreateCommandTest.php b/tests/N98/Magento/Command/Customer/CreateCommandTest.php
index 3d92bd3ae..aa4fa0682 100644
--- a/tests/N98/Magento/Command/Customer/CreateCommandTest.php
+++ b/tests/N98/Magento/Command/Customer/CreateCommandTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\Customer;
 
 use Mage;
@@ -7,33 +9,33 @@
 use N98\Magento\Command\TestCase;
 use Symfony\Component\Console\Tester\CommandTester;
 
-class CreateCommandTest extends TestCase
+final class CreateCommandTest extends TestCase
 {
     /**
      * @outputBuffering
      */
     public function testExecute()
     {
-        $command = $this->_getCommand();
+        $createCommand = $this->_getCommand();
         $generatedEmail = uniqid('', true) . '@example.com';
 
         $this->getApplication()->initMagento();
 
         $website = Mage::app()->getWebsite();
 
-        $commandTester = new CommandTester($command);
-        $options = ['command'   => $command->getName(), 'email'     => $generatedEmail, 'password'  => 'password123', 'firstname' => 'John', 'lastname'  => 'Doe', 'website'   => $website->getCode()];
+        $commandTester = new CommandTester($createCommand);
+        $options = ['command'   => $createCommand->getName(), 'email'     => $generatedEmail, 'password'  => 'password123', 'firstname' => 'John', 'lastname'  => 'Doe', 'website'   => $website->getCode()];
         $commandTester->execute($options);
-        self::assertMatchesRegularExpression('/Customer ' . $generatedEmail . ' successfully created/', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression('/Customer ' . $generatedEmail . ' successfully created/', $commandTester->getDisplay());
 
         // Format option
-        $commandTester = new CommandTester($command);
+        $commandTester = new CommandTester($createCommand);
         $generatedEmail = uniqid('', true) . '@example.com';
         $options['email'] = $generatedEmail;
         $options['--format'] = 'csv';
-        self::assertEquals(0, $commandTester->execute($options));
-        self::assertStringContainsString('email,password,firstname,lastname', $commandTester->getDisplay());
-        self::assertStringContainsString($generatedEmail . ',password123,John,Doe', $commandTester->getDisplay());
+        $this->assertSame(0, $commandTester->execute($options));
+        $this->assertStringContainsString('email,password,firstname,lastname', $commandTester->getDisplay());
+        $this->assertStringContainsString($generatedEmail . ',password123,John,Doe', $commandTester->getDisplay());
     }
 
     public function testWithWrongPassword()
@@ -60,13 +62,13 @@ public function testWithWrongPassword()
         $options = ['command'   => $command->getName(), 'email'     => $generatedEmail, 'password'  => 'pass', 'firstname' => 'John', 'lastname'  => 'Doe'];
         $commandTester = new CommandTester($command);
         $commandTester->execute($options);
-        self::assertMatchesRegularExpression('/The password must have at least 6 characters. Leading or trailing spaces will be ignored./', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression('/The password must have at least 6 characters. Leading or trailing spaces will be ignored./', $commandTester->getDisplay());
     }
 
     /**
      * @return CreateCommand
      */
-    protected function _getCommand()
+    private function _getCommand()
     {
         $application = $this->getApplication();
         $application->add(new CreateCommand());
diff --git a/tests/N98/Magento/Command/Customer/DeleteCommandTest.php b/tests/N98/Magento/Command/Customer/DeleteCommandTest.php
index 231566f7b..94e5f688c 100644
--- a/tests/N98/Magento/Command/Customer/DeleteCommandTest.php
+++ b/tests/N98/Magento/Command/Customer/DeleteCommandTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\Customer;
 
 use Mage;
@@ -12,27 +14,31 @@
 use Symfony\Component\Console\Helper\QuestionHelper;
 use Symfony\Component\Console\Tester\CommandTester;
 
-class DeleteCommandTest extends TestCase
+final class DeleteCommandTest extends TestCase
 {
-    protected $command;
-    protected $customerModel;
-    protected $customerCollection;
-    protected $questionHelper;
-    protected $parameterHelper;
-    protected $website;
-    protected $application;
-
-    protected function getResourceClassName($mage1Code)
+    private $command;
+
+    private $customerModel;
+
+    private $customerCollection;
+
+    private $questionHelper;
+
+    private $parameterHelper;
+
+
+
+    private function getResourceClassName($mage1Code)
     {
         return get_class(Mage::getResourceModel($mage1Code));
     }
 
-    protected function getModelClassName($mage1Code)
+    private function getModelClassName($mage1Code)
     {
         return get_class(Mage::getModel($mage1Code));
     }
 
-    protected function getCustomerModel(array $methods)
+    private function getCustomerModel(array $methods)
     {
         $className = $this->getModelClassName('customer/customer');
         return $this->getMockBuilder($className)
@@ -41,7 +47,7 @@ protected function getCustomerModel(array $methods)
             ->getMock();
     }
 
-    protected function getCustomerCollection(array $methods)
+    private function getCustomerCollection(array $methods)
     {
         $className = $this->getResourceClassName('customer/customer_collection');
         return $this->getMockBuilder($className)
@@ -53,8 +59,8 @@ protected function getCustomerCollection(array $methods)
     protected function setUp(): void
     {
         $this->markTestIncomplete('This tests are not compatible with PHPUnit 9. Refactring is needed.');
-        $this->application = $this->getApplication();
-        $this->application->initMagento();
+        $application = $this->getApplication();
+        $application->initMagento();
 
         $this->customerModel = $this->getCustomerModel(['loadByEmail', 'load', 'getId', 'delete', 'setWebsiteId']);
         $this->customerCollection = $this->getCustomerCollection(['addAttributeToSelect', 'addAttributeToFilter']);
@@ -71,7 +77,7 @@ protected function setUp(): void
             ->onlyMethods(['askWebsite'])
             ->getMock();
 
-        $this->website = $this->getMockBuilder('Mage_Core_Model_Website')
+        $website = $this->getMockBuilder('Mage_Core_Model_Website')
             ->setMethods(['getId'])
             ->getMock();
 
@@ -89,9 +95,9 @@ protected function setUp(): void
 
         $this->parameterHelper
             ->method('askWebsite')
-            ->willReturn($this->website);
+            ->willReturn($website);
 
-        $this->website
+        $website
             ->method('getId')
             ->willReturn(1);
     }
@@ -99,7 +105,7 @@ protected function setUp(): void
     public function testCanDeleteById()
     {
         $this->customerModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('load')
             ->with('1')
             ->willReturn($this->customerModel);
@@ -115,15 +121,16 @@ public function testCanDeleteById()
             ->willReturn(1);
 
         $this->customerModel
-            ->expects(self::never())
+            ->expects($this->never())
             ->method('loadByEmail');
 
         $this->customerModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('delete');
 
         $application = $this->getApplication();
         $application->add($this->command);
+
         $command = $this->getApplication()->find('customer:delete');
         $command->getHelperSet()->set($this->questionHelper, 'question');
 
@@ -132,13 +139,13 @@ public function testCanDeleteById()
             ['command' => $command->getName(), 'id' => '1', '--force'   => true],
         );
 
-        self::assertStringContainsString('successfully deleted', $commandTester->getDisplay());
+        $this->assertStringContainsString('successfully deleted', $commandTester->getDisplay());
     }
 
     public function testCanDeleteByEmail()
     {
         $this->customerModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('load')
             ->with('mike@testing.com')
             ->willReturn($this->customerModel);
@@ -149,13 +156,13 @@ public function testCanDeleteByEmail()
             ->willReturn(null);
 
         $this->customerModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('setWebsiteId')
             ->with(1)
             ->willReturn($this->customerModel);
 
         $this->customerModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('loadByEmail')
             ->with('mike@testing.com')
             ->willReturn($this->customerModel);
@@ -166,11 +173,12 @@ public function testCanDeleteByEmail()
             ->willReturn(1);
 
         $this->customerModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('delete');
 
         $application = $this->getApplication();
         $application->add($this->command);
+
         $command = $this->getApplication()->find('customer:delete');
         $command->getHelperSet()->set($this->questionHelper, 'question');
 
@@ -179,13 +187,13 @@ public function testCanDeleteByEmail()
             ['command'   => $command->getName(), 'id'        => 'mike@testing.com', '--force'   => true],
         );
 
-        self::assertStringContainsString('successfully deleted', $commandTester->getDisplay());
+        $this->assertStringContainsString('successfully deleted', $commandTester->getDisplay());
     }
 
     public function testCustomerNotFound()
     {
         $this->customerModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('load')
             ->with('mike@testing.com')
             ->willReturn($this->customerModel);
@@ -196,19 +204,20 @@ public function testCustomerNotFound()
             ->willReturn(null);
 
         $this->customerModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('setWebsiteId')
             ->with(1)
             ->willReturn($this->customerModel);
 
         $this->customerModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('loadByEmail')
             ->with('mike@testing.com')
             ->willReturn($this->customerModel);
 
         $application = $this->getApplication();
         $application->add($this->command);
+
         $command = $this->getApplication()->find('customer:delete');
         $command->getHelperSet()->set($this->questionHelper, 'question');
 
@@ -217,13 +226,13 @@ public function testCustomerNotFound()
             ['command'   => $command->getName(), 'id'        => 'mike@testing.com', '--force'   => true],
         );
 
-        self::assertStringContainsString('No customer found!', $commandTester->getDisplay());
+        $this->assertStringContainsString('No customer found!', $commandTester->getDisplay());
     }
 
     public function testDeleteFailed()
     {
         $this->customerModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('load')
             ->with('1')
             ->willReturn($this->customerModel);
@@ -239,16 +248,17 @@ public function testDeleteFailed()
             ->willReturn(1);
 
         $this->customerModel
-            ->expects(self::never())
+            ->expects($this->never())
             ->method('loadByEmail');
 
         $this->customerModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('delete')
-            ->will(self::throwException(new Exception('Failed to save')));
+            ->willThrowException(new Exception('Failed to save'));
 
         $application = $this->getApplication();
         $application->add($this->command);
+
         $command = $this->getApplication()->find('customer:delete');
 
         $commandTester = new CommandTester($command);
@@ -258,7 +268,7 @@ public function testDeleteFailed()
             ['command'   => $command->getName(), 'id'        => '1', '--force'   => true],
         );
 
-        self::assertStringContainsString('Failed to save', $commandTester->getDisplay());
+        $this->assertStringContainsString('Failed to save', $commandTester->getDisplay());
     }
 
     public function testPromptForCustomerIdAndDelete()
@@ -274,7 +284,7 @@ public function testPromptForCustomerIdAndDelete()
             ->willReturn('1');
 
         $this->customerModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('load')
             ->with('1')
             ->willReturn($this->customerModel);
@@ -290,15 +300,16 @@ public function testPromptForCustomerIdAndDelete()
             ->willReturn(1);
 
         $this->customerModel
-            ->expects(self::never())
+            ->expects($this->never())
             ->method('loadByEmail');
 
         $this->customerModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('delete');
 
         $application = $this->getApplication();
         $application->add($this->command);
+
         $command = $this->getApplication()->find('customer:delete');
         $command->getHelperSet()->set($this->questionHelper, 'question');
         $command->getHelperSet()->set($this->parameterHelper, 'parameter');
@@ -309,23 +320,24 @@ public function testPromptForCustomerIdAndDelete()
             ['command'   => $command->getName(), '--force'   => true],
         );
 
-        self::assertStringContainsString('successfully deleted', $commandTester->getDisplay());
+        $this->assertStringContainsString('successfully deleted', $commandTester->getDisplay());
     }
 
     public function testBatchDeleteGetsCustomerCollection()
     {
         $this->customerCollection
-            ->expects(self::atLeastOnce())
+            ->expects($this->atLeastOnce())
             ->method('addAttributeToSelect')
             ->willReturnMap([['firstname', false, $this->customerCollection], ['lastname', false, $this->customerCollection], ['email', false, $this->customerCollection]]);
 
         $this->questionHelper
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('ask')
             ->willReturn(false);
 
         $application = $this->getApplication();
         $application->add($this->command);
+
         $command = $this->getApplication()->find('customer:delete');
 
         $commandTester = new CommandTester($command);
@@ -335,13 +347,13 @@ public function testBatchDeleteGetsCustomerCollection()
             ['command'   => $command->getName(), '--all'     => true],
         );
 
-        self::assertStringContainsString('Aborting delete', $commandTester->getDisplay());
+        $this->assertStringContainsString('Aborting delete', $commandTester->getDisplay());
     }
 
     public function testRangeDeleteGetsCustomerCollection()
     {
         $this->customerCollection
-            ->expects(self::atLeastOnce())
+            ->expects($this->atLeastOnce())
             ->method('addAttributeToSelect')
             ->willReturnMap([['firstname', false, $this->customerCollection], ['lastname', false, $this->customerCollection], ['email', false, $this->customerCollection]]);
 
@@ -360,7 +372,7 @@ public function testRangeDeleteGetsCustomerCollection()
             ->willReturn('10');
 
         $this->customerCollection
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('addAttributeToFilter')
             ->willReturn($this->customerCollection);
 
@@ -371,6 +383,7 @@ public function testRangeDeleteGetsCustomerCollection()
 
         $application = $this->getApplication();
         $application->add($this->command);
+
         $command = $this->getApplication()->find('customer:delete');
 
         $commandTester = new CommandTester($command);
@@ -380,13 +393,13 @@ public function testRangeDeleteGetsCustomerCollection()
             ['command'   => $command->getName(), '--range'   => true],
         );
 
-        self::assertStringContainsString('Aborting delete', $commandTester->getDisplay());
+        $this->assertStringContainsString('Aborting delete', $commandTester->getDisplay());
     }
 
     public function testShouldRemoveStopsDeletion()
     {
         $this->customerModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('load')
             ->with('1')
             ->willReturn($this->customerModel);
@@ -402,20 +415,21 @@ public function testShouldRemoveStopsDeletion()
             ->willReturn(1);
 
         $this->customerModel
-            ->expects(self::never())
+            ->expects($this->never())
             ->method('loadByEmail');
 
         $this->questionHelper
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('askConfirmation')
             ->willReturn(false);
 
         $this->customerModel
-            ->expects(self::never())
+            ->expects($this->never())
             ->method('delete');
 
         $application = $this->getApplication();
         $application->add($this->command);
+
         $command = $this->getApplication()->find('customer:delete');
 
         $commandTester = new CommandTester($command);
@@ -425,13 +439,13 @@ public function testShouldRemoveStopsDeletion()
             ['command'   => $command->getName(), 'id'        => '1'],
         );
 
-        self::assertStringContainsString('Aborting delete', $commandTester->getDisplay());
+        $this->assertStringContainsString('Aborting delete', $commandTester->getDisplay());
     }
 
     public function testShouldRemovePromptAllowsDeletion()
     {
         $this->customerModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('load')
             ->with('1')
             ->willReturn($this->customerModel);
@@ -447,20 +461,21 @@ public function testShouldRemovePromptAllowsDeletion()
             ->willReturn(1);
 
         $this->customerModel
-            ->expects(self::never())
+            ->expects($this->never())
             ->method('loadByEmail');
 
         $this->questionHelper
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('askConfirmation')
             ->willReturn(true);
 
         $this->customerModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('delete');
 
         $application = $this->getApplication();
         $application->add($this->command);
+
         $command = $this->getApplication()->find('customer:delete');
 
         $commandTester = new CommandTester($command);
@@ -470,18 +485,18 @@ public function testShouldRemovePromptAllowsDeletion()
             ['command'   => $command->getName(), 'id'        => '1'],
         );
 
-        self::assertStringContainsString('successfully deleted', $commandTester->getDisplay());
+        $this->assertStringContainsString('successfully deleted', $commandTester->getDisplay());
     }
 
     public function testPromptDeleteAllAndDeleteRangeAndAbort()
     {
         $this->questionHelper
             ->expects(self::exactly(3))
-            ->method('askConfirmation')
-            ->will(self::onConsecutiveCalls(true, false, false));
+            ->method('askConfirmation')->willReturnOnConsecutiveCalls(true, false, false);
 
         $application = $this->getApplication();
         $application->add($this->command);
+
         $command = $this->getApplication()->find('customer:delete');
 
         $commandTester = new CommandTester($command);
@@ -491,7 +506,7 @@ public function testPromptDeleteAllAndDeleteRangeAndAbort()
             ['command'   => $command->getName()],
         );
 
-        self::assertStringContainsString('nothing to do', $commandTester->getDisplay());
+        $this->assertStringContainsString('nothing to do', $commandTester->getDisplay());
     }
 
     public function testPromptAllCanDeleteAll()
@@ -499,7 +514,7 @@ public function testPromptAllCanDeleteAll()
         $this->questionHelper
             ->expects(self::exactly(2))
             ->method('askConfirmation')
-            ->will(self::onConsecutiveCalls(true, true));
+            ->willReturn(true);
 
         $this->customerCollection
             ->expects(self::exactly(3))
@@ -507,13 +522,14 @@ public function testPromptAllCanDeleteAll()
             ->willReturnMap([['firstname', false, $this->customerCollection], ['lastname', false, $this->customerCollection], ['email', false, $this->customerCollection]]);
 
         $this->command
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('batchDelete')
             ->with($this->customerCollection)
             ->willReturn(3);
 
         $application = $this->getApplication();
         $application->add($this->command);
+
         $command = $this->getApplication()->find('customer:delete');
         $command->getHelperSet()->set($this->questionHelper, 'question');
 
@@ -522,18 +538,17 @@ public function testPromptAllCanDeleteAll()
             ['command'   => $command->getName(), '--force'   => true],
         );
 
-        self::assertStringContainsString('Successfully deleted 3 customer/s', $commandTester->getDisplay());
+        $this->assertStringContainsString('Successfully deleted 3 customer/s', $commandTester->getDisplay());
     }
 
     public function testPromptRangeCanDeleteRange()
     {
         $this->questionHelper
             ->expects(self::exactly(3))
-            ->method('askConfirmation')
-            ->will(self::onConsecutiveCalls(true, false, true));
+            ->method('askConfirmation')->willReturnOnConsecutiveCalls(true, false, true);
 
         $this->customerCollection
-            ->expects(self::atLeastOnce())
+            ->expects($this->atLeastOnce())
             ->method('addAttributeToSelect')
             ->willReturnMap([['firstname', false, $this->customerCollection], ['lastname', false, $this->customerCollection], ['email', false, $this->customerCollection]]);
 
@@ -552,18 +567,18 @@ public function testPromptRangeCanDeleteRange()
             ->willReturn('10');
 
         $this->customerCollection
-            ->expects(self::once())
-            ->method('addAttributeToFilter')
-            ->will(self::returnSelf());
+            ->expects($this->once())
+            ->method('addAttributeToFilter')->willReturnSelf();
 
         $this->command
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('batchDelete')
             ->with($this->customerCollection)
             ->willReturn(3);
 
         $application = $this->getApplication();
         $application->add($this->command);
+
         $command = $this->getApplication()->find('customer:delete');
 
         $commandTester = new CommandTester($command);
@@ -571,7 +586,7 @@ public function testPromptRangeCanDeleteRange()
             ['command'   => $command->getName(), '--force'   => true],
         );
 
-        self::assertStringContainsString('Successfully deleted 3 customer/s', $commandTester->getDisplay());
+        $this->assertStringContainsString('Successfully deleted 3 customer/s', $commandTester->getDisplay());
     }
 
     public function testBatchDelete()
@@ -583,37 +598,36 @@ public function testBatchDelete()
 
         $command
             ->expects(self::exactly(2))
-            ->method('deleteCustomer')
-            ->will(self::onConsecutiveCalls(true, new Exception('Failed to delete')));
+            ->method('deleteCustomer')->willReturnOnConsecutiveCalls(true, new Exception('Failed to delete'));
 
-        $refObject = new ReflectionObject($command);
-        $method = $refObject->getMethod('batchDelete');
-        $method->setAccessible(true);
+        $reflectionObject = new ReflectionObject($command);
+        $reflectionMethod = $reflectionObject->getMethod('batchDelete');
+        $reflectionMethod->setAccessible(true);
 
         $data = new ArrayIterator([$this->customerModel, $this->customerModel]);
 
         $collection = $this->getCustomerCollection(['getIterator']);
 
         $collection
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('getIterator')
             ->willReturn($data);
 
-        $result = $method->invokeArgs($command, [$collection]);
+        $result = $reflectionMethod->invokeArgs($command, [$collection]);
 
-        self::assertEquals(1, $result);
+        $this->assertSame(1, $result);
     }
 
     public function testValidateInt()
     {
         $this->expectException(RuntimeException::class);
         $this->expectExceptionMessage('The range should be numeric and above 0 e.g. 1');
-        $refObject = new ReflectionObject($this->command);
-        $method = $refObject->getMethod('validateInt');
-        $method->setAccessible(true);
+        $reflectionObject = new ReflectionObject($this->command);
+        $reflectionMethod = $reflectionObject->getMethod('validateInt');
+        $reflectionMethod->setAccessible(true);
 
-        $resultValid = $method->invokeArgs($this->command, ['5']);
-        self::assertEquals(5, $resultValid);
-        $method->invokeArgs($this->command, ['bad input']); // Exception!
+        $resultValid = $reflectionMethod->invokeArgs($this->command, ['5']);
+        $this->assertSame(5, $resultValid);
+        $reflectionMethod->invokeArgs($this->command, ['bad input']); // Exception!
     }
 }
diff --git a/tests/N98/Magento/Command/Customer/ListCommandTest.php b/tests/N98/Magento/Command/Customer/ListCommandTest.php
index a6f995944..a2593703a 100644
--- a/tests/N98/Magento/Command/Customer/ListCommandTest.php
+++ b/tests/N98/Magento/Command/Customer/ListCommandTest.php
@@ -1,21 +1,24 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\Customer;
 
 use N98\Magento\Command\TestCase;
 use Symfony\Component\Console\Tester\CommandTester;
 
-class ListCommandTest extends TestCase
+final class ListCommandTest extends TestCase
 {
     public function testExecute()
     {
         $application = $this->getApplication();
         $application->add(new ListCommand());
+
         $command = $this->getApplication()->find('customer:list');
 
         $commandTester = new CommandTester($command);
         $commandTester->execute(['command' => $command->getName()]);
 
-        self::assertMatchesRegularExpression('/email/', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression('/email/', $commandTester->getDisplay());
     }
 }
diff --git a/tests/N98/Magento/Command/Database/DumpCommandTest.php b/tests/N98/Magento/Command/Database/DumpCommandTest.php
index f53250280..8002853e3 100644
--- a/tests/N98/Magento/Command/Database/DumpCommandTest.php
+++ b/tests/N98/Magento/Command/Database/DumpCommandTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\Database;
 
 use InvalidArgumentException;
@@ -11,12 +13,12 @@
 /**
  * @see \N98\Magento\Command\Database\DumpCommand
  */
-class DumpCommandTest extends TestCase
+final class DumpCommandTest extends TestCase
 {
     /**
      * @return Command
      */
-    protected function getCommand()
+    private function getCommand()
     {
         $dumpCommand = new DumpCommand();
         if (!$dumpCommand->isEnabled()) {
@@ -25,9 +27,8 @@ protected function getCommand()
 
         $application = $this->getApplication();
         $application->add($dumpCommand);
-        $command = $this->getApplication()->find('db:dump');
 
-        return $command;
+        return $this->getApplication()->find('db:dump');
     }
 
     public function testExecute()
@@ -39,43 +40,39 @@ public function testExecute()
             ['command'        => $command->getName(), '--add-time'     => true, '--only-command' => true, '--force'        => true, '--compression'  => 'gz'],
         );
 
-        self::assertMatchesRegularExpression('/mysqldump/', $commandTester->getDisplay());
-        self::assertMatchesRegularExpression('/\.sql/', $commandTester->getDisplay());
-        self::assertStringContainsString('.sql.gz', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression('/mysqldump/', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression('/\.sql/', $commandTester->getDisplay());
+        $this->assertStringContainsString('.sql.gz', $commandTester->getDisplay());
     }
 
     /**
      * @see filenamePatterns
      */
-    public function provideFilenamePatternsAndOptions()
+    public function provideFilenamePatternsAndOptions(): \Iterator
     {
-        return [
-            # testAddTimeAutogenerated
-            ['/^.*[0-9]{4}-[0-9]{2}-[0-9]{2}_[0-9]{6}\.sql$/', []],
-            # testAddTimePrefixAutogenerated
-            ['/^[0-9]{4}-[0-9]{2}-[0-9]{2}_[0-9]{6}.*\.sql$/', ['--add-time' => 'prefix']],
-            # testAddTimeFilenameSpecified
-            ['/^.*[0-9]{4}-[0-9]{2}-[0-9]{2}_[0-9]{6}\.sql.gz$/', ['--compression' => 'gzip']],
-            # testAddTimeFilenameSpecified
-            ['/^foo_[0-9]{4}-[0-9]{2}-[0-9]{2}_[0-9]{6}\.sql$/', ['filename' => 'foo.sql']],
-            # testAddTimePrefixFilenameSpecified
-            ['/^[0-9]{4}-[0-9]{2}-[0-9]{2}_[0-9]{6}_foo\.sql$/', ['filename' => 'foo.sql', '--add-time' => 'prefix']],
-            # testAddTimeOffFilenameSpecified
-            ['/^foo.sql$/', ['filename' => 'foo.sql', '--add-time' => 'no']],
-            # testAddTimeFilenameSpecifiedRelative
-            ['/^..\/foo_[0-9]{4}-[0-9]{2}-[0-9]{2}_[0-9]{6}\.sql$/', ['filename' => '../foo.sql']],
-        ];
+        # testAddTimeAutogenerated
+        yield ['/^.*\d{4}-\d{2}-\d{2}_\d{6}\.sql$/', []];
+        # testAddTimePrefixAutogenerated
+        yield ['/^\d{4}-\d{2}-\d{2}_\d{6}.*\.sql$/', ['--add-time' => 'prefix']];
+        # testAddTimeFilenameSpecified
+        yield ['/^.*\d{4}-\d{2}-\d{2}_\d{6}\.sql.gz$/', ['--compression' => 'gzip']];
+        # testAddTimeFilenameSpecified
+        yield ['/^foo_\d{4}-\d{2}-\d{2}_\d{6}\.sql$/', ['filename' => 'foo.sql']];
+        # testAddTimePrefixFilenameSpecified
+        yield ['/^\d{4}-\d{2}-\d{2}_\d{6}_foo\.sql$/', ['filename' => 'foo.sql', '--add-time' => 'prefix']];
+        # testAddTimeOffFilenameSpecified
+        yield ['/^foo.sql$/', ['filename' => 'foo.sql', '--add-time' => 'no']];
+        # testAddTimeFilenameSpecifiedRelative
+        yield ['/^..\/foo_\d{4}-\d{2}-\d{2}_\d{6}\.sql$/', ['filename' => '../foo.sql']];
     }
 
     /**
-     * @test
      * @dataProvider provideFilenamePatternsAndOptions
      *
      * @param string $regex
-     * @param array $options
      * @return void
      */
-    public function filenamePatterns($regex, array $options)
+    public function testFilenamePatterns($regex, array $options)
     {
         $command = $this->getCommand();
 
@@ -100,13 +97,13 @@ public function testWithStripOption()
         $dbConfig = $this->getDatabaseConnection()->getConfig();
         $db = $dbConfig['dbname'];
 
-        self::assertMatchesRegularExpression("/--ignore-table=$db.customer_entity/", $commandTester->getDisplay());
-        self::assertMatchesRegularExpression("/--ignore-table=$db.customer_address_entity/", $commandTester->getDisplay());
-        self::assertMatchesRegularExpression("/--ignore-table=$db.sales_flat_order/", $commandTester->getDisplay());
-        self::assertMatchesRegularExpression("/--ignore-table=$db.sales_flat_order_item/", $commandTester->getDisplay());
-        self::assertMatchesRegularExpression("/--ignore-table=$db.sales_flat_order_item/", $commandTester->getDisplay());
-        self::assertStringNotContainsString('not_existing_table_1', $commandTester->getDisplay());
-        self::assertStringContainsString('.sql.gz', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression(sprintf('/--ignore-table=%s.customer_entity/', $db), $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression(sprintf('/--ignore-table=%s.customer_address_entity/', $db), $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression(sprintf('/--ignore-table=%s.sales_flat_order/', $db), $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression(sprintf('/--ignore-table=%s.sales_flat_order_item/', $db), $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression(sprintf('/--ignore-table=%s.sales_flat_order_item/', $db), $commandTester->getDisplay());
+        $this->assertStringNotContainsString('not_existing_table_1', $commandTester->getDisplay());
+        $this->assertStringContainsString('.sql.gz', $commandTester->getDisplay());
 
         /**
          * Uncompressed
@@ -115,7 +112,7 @@ public function testWithStripOption()
         $commandTester->execute(
             ['command'        => $command->getName(), '--add-time'     => true, '--only-command' => true, '--force'        => true, '--strip'        => '@development'],
         );
-        self::assertStringNotContainsString('.sql.gz', $commandTester->getDisplay());
+        $this->assertStringNotContainsString('.sql.gz', $commandTester->getDisplay());
     }
 
     public function testWithIncludeExcludeOptions()
@@ -132,7 +129,7 @@ public function testWithIncludeExcludeOptions()
         $commandTester->execute(
             ['command'        => $command->getName(), '--add-time'     => true, '--only-command' => true, '--force'        => true, '--exclude'      => 'core_config_data', '--compression'  => 'gzip'],
         );
-        self::assertMatchesRegularExpression("/--ignore-table=$db\.core_config_data/", $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression(sprintf('/--ignore-table=%s\.core_config_data/', $db), $commandTester->getDisplay());
 
         /**
          * Include
@@ -141,8 +138,8 @@ public function testWithIncludeExcludeOptions()
         $commandTester->execute(
             ['command'        => $command->getName(), '--add-time'     => true, '--only-command' => true, '--force'        => true, '--include'      => 'core_config_data', '--compression'  => 'gzip'],
         );
-        self::assertDoesNotMatchRegularExpression("/--ignore-table=$db\.core_config_data/", $commandTester->getDisplay());
-        self::assertMatchesRegularExpression("/--ignore-table=$db\.catalog_product_entity/", $commandTester->getDisplay());
+        $this->assertDoesNotMatchRegularExpression(sprintf('/--ignore-table=%s\.core_config_data/', $db), $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression(sprintf('/--ignore-table=%s\.catalog_product_entity/', $db), $commandTester->getDisplay());
     }
 
     public function testIncludeExcludeMutualExclusivity()
@@ -161,16 +158,16 @@ public function testIncludeExcludeMutualExclusivity()
     }
 
     /**
-     * @test
      * @link https://github.com/netz98/n98-magerun2/issues/200
      */
-    public function realDump()
+    public function testRealDump()
     {
         $dumpFile = new SplFileInfo($this->getTestMagentoRoot() . '/test-dump.sql');
         if ($dumpFile->isReadable()) {
-            self::assertTrue(unlink($dumpFile), 'Precondition to unlink that the file does not exists');
+            $this->assertTrue(unlink((string) $dumpFile), 'Precondition to unlink that the file does not exists');
         }
-        self::assertIsNotReadable((string) $dumpFile, 'Precondition that the file does not exists');
+
+        $this->assertIsNotReadable((string) $dumpFile, 'Precondition that the file does not exists');
 
         $command = $this->getCommand();
         $commandTester = new CommandTester($command);
@@ -178,8 +175,8 @@ public function realDump()
             ['command'  => $command->getName(), '--strip'  => '@stripped', 'filename' => $dumpFile],
         );
 
-        self::assertTrue($dumpFile->isReadable(), 'File was created');
+        $this->assertTrue($dumpFile->isReadable(), 'File was created');
         // dump should be larger than quarter a megabyte
-        self::assertGreaterThan(250000, $dumpFile->getSize());
+        $this->assertGreaterThan(250000, $dumpFile->getSize());
     }
 }
diff --git a/tests/N98/Magento/Command/Database/InfoCommandTest.php b/tests/N98/Magento/Command/Database/InfoCommandTest.php
index cc9d86f2b..cf6945742 100644
--- a/tests/N98/Magento/Command/Database/InfoCommandTest.php
+++ b/tests/N98/Magento/Command/Database/InfoCommandTest.php
@@ -1,28 +1,32 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\Database;
 
 use N98\Magento\Command\TestCase;
 use Symfony\Component\Console\Tester\CommandTester;
 
-class InfoCommandTest extends TestCase
+final class InfoCommandTest extends TestCase
 {
     public function testExecute()
     {
         $application = $this->getApplication();
         $application->add(new InfoCommand());
+
         $command = $this->getApplication()->find('db:info');
 
         $commandTester = new CommandTester($command);
         $commandTester->execute(['command' => $command->getName()]);
 
-        self::assertMatchesRegularExpression('/PDO-Connection-String/', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression('/PDO-Connection-String/', $commandTester->getDisplay());
     }
 
     public function testExecuteWithSettingArgument()
     {
         $application = $this->getApplication();
         $application->add(new InfoCommand());
+
         $command = $this->getApplication()->find('db:info');
 
         $commandTester = new CommandTester($command);
@@ -30,7 +34,7 @@ public function testExecuteWithSettingArgument()
             ['command' => $command->getName(), 'setting' => 'MySQL-Cli-String'],
         );
 
-        self::assertDoesNotMatchRegularExpression('/MySQL-Cli-String/', $commandTester->getDisplay());
-        self::assertStringContainsString('mysql -h', $commandTester->getDisplay());
+        $this->assertDoesNotMatchRegularExpression('/MySQL-Cli-String/', $commandTester->getDisplay());
+        $this->assertStringContainsString('mysql -h', $commandTester->getDisplay());
     }
 }
diff --git a/tests/N98/Magento/Command/Database/Maintain/CheckTablesCommandTest.php b/tests/N98/Magento/Command/Database/Maintain/CheckTablesCommandTest.php
index be68304b4..7d3261eef 100644
--- a/tests/N98/Magento/Command/Database/Maintain/CheckTablesCommandTest.php
+++ b/tests/N98/Magento/Command/Database/Maintain/CheckTablesCommandTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\Database\Maintain;
 
 use Symfony\Component\Console\Command\Command;
@@ -9,7 +11,7 @@
 /**
  * @see \N98\Magento\Command\Database\Maintain\CheckTablesCommand
  */
-class CheckTablesCommandTest extends TestCase
+final class CheckTablesCommandTest extends TestCase
 {
     public function testExecute()
     {
@@ -19,27 +21,20 @@ public function testExecute()
         $commandTester->execute(
             ['command'  => $command->getName(), '--format' => 'csv', '--type'   => 'quick', '--table'  => 'catalogsearch_*'],
         );
-        self::assertStringContainsString('catalogsearch_fulltext,check,quick,OK', $commandTester->getDisplay());
+        $this->assertStringContainsString('catalogsearch_fulltext,check,quick,OK', $commandTester->getDisplay());
         $timeRegex = '"\s+[0-9]+\srows","[0-9\.]+\ssecs"';
-        self::assertMatchesRegularExpression(
-            '~catalogsearch_query,"ENGINE InnoDB",' . $timeRegex . '~',
-            $commandTester->getDisplay(),
-        );
-        self::assertMatchesRegularExpression(
-            '~catalogsearch_result,"ENGINE InnoDB",' . $timeRegex . '~',
-            $commandTester->getDisplay(),
-        );
+        $this->assertMatchesRegularExpression('~catalogsearch_query,"ENGINE InnoDB",' . $timeRegex . '~', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression('~catalogsearch_result,"ENGINE InnoDB",' . $timeRegex . '~', $commandTester->getDisplay());
     }
 
     /**
      * @return Command
      */
-    protected function getCommand()
+    private function getCommand()
     {
         $application = $this->getApplication();
         $application->add(new CheckTablesCommand());
-        $command = $this->getApplication()->find('db:maintain:check-tables');
 
-        return $command;
+        return $this->getApplication()->find('db:maintain:check-tables');
     }
 }
diff --git a/tests/N98/Magento/Command/Database/QueryCommandTest.php b/tests/N98/Magento/Command/Database/QueryCommandTest.php
index a133c1356..42cb19517 100644
--- a/tests/N98/Magento/Command/Database/QueryCommandTest.php
+++ b/tests/N98/Magento/Command/Database/QueryCommandTest.php
@@ -1,16 +1,19 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\Database;
 
 use N98\Magento\Command\TestCase;
 use Symfony\Component\Console\Tester\CommandTester;
 
-class QueryCommandTest extends TestCase
+final class QueryCommandTest extends TestCase
 {
     public function testExecute()
     {
         $application = $this->getApplication();
         $application->add(new QueryCommand());
+
         $command = $this->getApplication()->find('db:query');
 
         $commandTester = new CommandTester($command);
@@ -18,8 +21,8 @@ public function testExecute()
             ['command' => $command->getName(), 'query'   => 'SHOW TABLES;'],
         );
 
-        self::assertStringContainsString('admin_user', $commandTester->getDisplay());
-        self::assertStringContainsString('catalog_product_entity', $commandTester->getDisplay());
-        self::assertStringContainsString('wishlist', $commandTester->getDisplay());
+        $this->assertStringContainsString('admin_user', $commandTester->getDisplay());
+        $this->assertStringContainsString('catalog_product_entity', $commandTester->getDisplay());
+        $this->assertStringContainsString('wishlist', $commandTester->getDisplay());
     }
 }
diff --git a/tests/N98/Magento/Command/Database/StatusCommandTest.php b/tests/N98/Magento/Command/Database/StatusCommandTest.php
index 238767888..488780902 100644
--- a/tests/N98/Magento/Command/Database/StatusCommandTest.php
+++ b/tests/N98/Magento/Command/Database/StatusCommandTest.php
@@ -1,21 +1,22 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\Database;
 
 use N98\Magento\Command\TestCase;
 use Symfony\Component\Console\Tester\CommandTester;
 
-class StatusCommandTest extends TestCase
+final class StatusCommandTest extends TestCase
 {
     /**
-     * @param array $options
-     *
      * @return CommandTester
      */
-    protected function getCommand(array $options)
+    private function getCommand(array $options)
     {
         $application = $this->getApplication();
         $application->add(new StatusCommand());
+
         $command = $this->getApplication()->find('db:status');
 
         $commandTester = new CommandTester($command);
@@ -30,10 +31,10 @@ public function testExecute()
         $commandTester = $this->getCommand(['--format' => 'csv']);
         $display = $commandTester->getDisplay();
 
-        self::assertStringContainsString('Threads_connected', $display);
-        self::assertStringContainsString('Innodb_buffer_pool_wait_free', $display);
-        self::assertStringContainsString('InnoDB Buffer Pool hit', $display);
-        self::assertStringContainsString('Full table scans', $display);
+        $this->assertStringContainsString('Threads_connected', $display);
+        $this->assertStringContainsString('Innodb_buffer_pool_wait_free', $display);
+        $this->assertStringContainsString('InnoDB Buffer Pool hit', $display);
+        $this->assertStringContainsString('Full table scans', $display);
     }
 
     public function testSearch()
@@ -42,19 +43,16 @@ public function testSearch()
 
         $display = $commandTester->getDisplay();
 
-        self::assertStringContainsString('Innodb_buffer_pool_read_ahead_rnd', $display);
-        self::assertStringContainsString('Innodb_buffer_pool_wait_free', $display);
-        self::assertStringContainsString('InnoDB Buffer Pool hit', $display);
-        self::assertStringContainsString('Innodb_dblwr_pages_written', $display);
-        self::assertStringContainsString('Innodb_os_log_written', $display);
+        $this->assertStringContainsString('Innodb_buffer_pool_read_ahead_rnd', $display);
+        $this->assertStringContainsString('Innodb_buffer_pool_wait_free', $display);
+        $this->assertStringContainsString('InnoDB Buffer Pool hit', $display);
+        $this->assertStringContainsString('Innodb_dblwr_pages_written', $display);
+        $this->assertStringContainsString('Innodb_os_log_written', $display);
     }
 
     public function testRounding()
     {
         $commandTester = $this->getCommand(['--format'   => 'csv', '--rounding' => '2', 'search'     => '%size%']);
-        self::assertMatchesRegularExpression(
-            '~Innodb_page_size,[0-9\.]+K,~',
-            $commandTester->getDisplay(),
-        );
+        $this->assertMatchesRegularExpression('~Innodb_page_size,[0-9\.]+K,~', $commandTester->getDisplay());
     }
 }
diff --git a/tests/N98/Magento/Command/Database/VariablesCommandTest.php b/tests/N98/Magento/Command/Database/VariablesCommandTest.php
index d4ee9a3d8..83d6878bb 100644
--- a/tests/N98/Magento/Command/Database/VariablesCommandTest.php
+++ b/tests/N98/Magento/Command/Database/VariablesCommandTest.php
@@ -1,12 +1,14 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\Database;
 
 use N98\Magento\Command\TestCase;
 use N98\Util\Console\Helper\DatabaseHelper;
 use Symfony\Component\Console\Tester\CommandTester;
 
-class VariablesCommandTest extends TestCase
+final class VariablesCommandTest extends TestCase
 {
     /**
      * @var StatusCommand
@@ -14,16 +16,15 @@ class VariablesCommandTest extends TestCase
     private $statusCommand;
 
     /**
-     * @param array $options
-     *
      * @return CommandTester
      */
-    protected function getCommand(array $options)
+    private function getCommand(array $options)
     {
         $this->statusCommand = new StatusCommand();
 
         $application = $this->getApplication();
         $application->add($this->statusCommand);
+
         $command = $this->getApplication()->find('db:variables');
 
         $commandTester = new CommandTester($command);
@@ -47,10 +48,10 @@ public function testExecute()
         $commandTester = $this->getCommand(['--format' => 'csv']);
         $display = $commandTester->getDisplay();
 
-        self::assertStringContainsString('have_query_cache', $display);
-        self::assertStringContainsString('innodb_log_buffer_size', $display);
-        self::assertStringContainsString('max_connections', $display);
-        self::assertStringContainsString('thread_cache_size', $display);
+        $this->assertStringContainsString('have_query_cache', $display);
+        $this->assertStringContainsString('innodb_log_buffer_size', $display);
+        $this->assertStringContainsString('max_connections', $display);
+        $this->assertStringContainsString('thread_cache_size', $display);
     }
 
     /**
@@ -60,17 +61,18 @@ public function testSearch()
     {
         $commandTester = $this->getCommand(['--format' => 'csv', 'search'   => 'Innodb%']);
 
-        $dbHelper = $this->getDatabaseHelper();
+        $databaseHelper = $this->getDatabaseHelper();
 
         $display = $commandTester->getDisplay();
 
-        self::assertStringContainsString('innodb_concurrency_tickets', $display);
+        $this->assertStringContainsString('innodb_concurrency_tickets', $display);
         // innodb_force_load_corrupted Introduced in 5.6.3
-        if (-1 < version_compare($dbHelper->getMysqlVariable('version'), '5.6.3')) {
-            self::assertStringContainsString('innodb_force_load_corrupted', $display);
+        if (-1 < version_compare($databaseHelper->getMysqlVariable('version'), '5.6.3')) {
+            $this->assertStringContainsString('innodb_force_load_corrupted', $display);
         }
-        self::assertStringContainsString('innodb_log_file_size', $display);
-        self::assertMatchesRegularExpression('~innodb_(?:file|read)_io_threads~', $display);
+
+        $this->assertStringContainsString('innodb_log_file_size', $display);
+        $this->assertMatchesRegularExpression('~innodb_(?:file|read)_io_threads~', $display);
     }
 
     /**
@@ -80,15 +82,15 @@ public function testRounding()
     {
         $commandTester = $this->getCommand(['--format'   => 'csv', '--rounding' => '2', 'search'     => '%size%']);
 
-        $dbHelper = $this->getDatabaseHelper();
+        $databaseHelper = $this->getDatabaseHelper();
 
         $display = $commandTester->getDisplay();
 
-        self::assertMatchesRegularExpression('~myisam_max_sort_file_size,[0-9\.]+[A-Z]~', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression('~myisam_max_sort_file_size,[0-9\.]+[A-Z]~', $commandTester->getDisplay());
 
         // max_binlog_stmt_cache_size Introduced in 5.5.9
-        if (-1 < version_compare($dbHelper->getMysqlVariable('version'), '5.5.9')) {
-            self::assertMatchesRegularExpression('~max_binlog_stmt_cache_size,[0-9\.]+[A-Z]~', $display);
+        if (-1 < version_compare($databaseHelper->getMysqlVariable('version'), '5.5.9')) {
+            $this->assertMatchesRegularExpression('~max_binlog_stmt_cache_size,[0-9\.]+[A-Z]~', $display);
         }
     }
 }
diff --git a/tests/N98/Magento/Command/Design/DemoNoticeCommandTest.php b/tests/N98/Magento/Command/Design/DemoNoticeCommandTest.php
index 09b59e61d..629e04fa9 100644
--- a/tests/N98/Magento/Command/Design/DemoNoticeCommandTest.php
+++ b/tests/N98/Magento/Command/Design/DemoNoticeCommandTest.php
@@ -1,30 +1,33 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\Design;
 
 use N98\Magento\Command\TestCase;
 use Symfony\Component\Console\Tester\CommandTester;
 
-class DemoNoticeCommandTest extends TestCase
+final class DemoNoticeCommandTest extends TestCase
 {
     public function testExecute()
     {
         $application = $this->getApplication();
         $application->add(new DemoNoticeCommand());
         $application->setAutoExit(false);
+
         $command = $this->getApplication()->find('design:demo-notice');
 
         $commandTester = new CommandTester($command);
         $commandTester->execute(
             ['command'  => $command->getName(), 'store'    => 'admin', '--on'     => true],
         );
-        self::assertMatchesRegularExpression('/Demo Notice enabled/', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression('/Demo Notice enabled/', $commandTester->getDisplay());
 
         $commandTester = new CommandTester($command);
         $commandTester->execute(
             ['command'  => $command->getName(), 'store'    => 'admin', '--off'    => true],
         );
 
-        self::assertMatchesRegularExpression('/Demo Notice disabled/', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression('/Demo Notice disabled/', $commandTester->getDisplay());
     }
 }
diff --git a/tests/N98/Magento/Command/Developer/ClassLookupCommandTest.php b/tests/N98/Magento/Command/Developer/ClassLookupCommandTest.php
index 0b1f83645..b7423b5b2 100644
--- a/tests/N98/Magento/Command/Developer/ClassLookupCommandTest.php
+++ b/tests/N98/Magento/Command/Developer/ClassLookupCommandTest.php
@@ -1,11 +1,13 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\Developer;
 
 use N98\Magento\Command\TestCase;
 use Symfony\Component\Console\Tester\CommandTester;
 
-class ClassLookupCommandTest extends TestCase
+final class ClassLookupCommandTest extends TestCase
 {
     /**
      * Test that the class lookup command resolves to the expected Magento class, and optionally
@@ -21,6 +23,7 @@ public function testExecute($type, $name, $expected, $exists)
     {
         $application = $this->getApplication();
         $application->add(new ClassLookupCommand());
+
         $command = $this->getApplication()->find('dev:class:lookup');
 
         $commandTester = new CommandTester($command);
@@ -29,9 +32,9 @@ public function testExecute($type, $name, $expected, $exists)
         );
 
         $output = $commandTester->getDisplay();
-        self::assertMatchesRegularExpression(sprintf('/%s/', $expected), $output);
+        $this->assertMatchesRegularExpression(sprintf('/%s/', $expected), $output);
 
-        $existsAssertion = (!$exists) ? 'assertMatchesRegularExpression' : 'assertDoesNotMatchRegularExpression';
+        $existsAssertion = ($exists) ? 'assertDoesNotMatchRegularExpression' : 'assertMatchesRegularExpression';
         $this->{$existsAssertion}(sprintf('/%s/', 'does not exist'), $output);
     }
 
@@ -41,6 +44,13 @@ public function testExecute($type, $name, $expected, $exists)
      */
     public function classLookupProvider()
     {
-        return [['type'     => 'model', 'name'     => 'catalog/product', 'expected' => 'Mage_Catalog_Model_Product', 'exists'   => true], ['type'     => 'model', 'name'     => 'catalog/nothing_to_see_here', 'expected' => 'Mage_Catalog_Model_Nothing_To_See_Here', 'exists'   => false], ['type'     => 'helper', 'name'     => 'checkout/cart', 'expected' => 'Mage_Checkout_Helper_Cart', 'exists'   => true], ['type'     => 'helper', 'name'     => 'checkout/stolen_creditcards', 'expected' => 'Mage_Checkout_Helper_Stolen_Creditcards', 'exists'   => false], ['type'     => 'block', 'name'     => 'customer/account_dashboard', 'expected' => 'Mage_Customer_Block_Account_Dashboard', 'exists'   => true], ['type'     => 'block', 'name'     => 'customer/my_code_snippets', 'expected' => 'Mage_Customer_Block_My_Code_Snippets', 'exists'   => false]];
+        return [
+            ['type'     => 'model', 'name'     => 'catalog/product', 'expected' => 'Mage_Catalog_Model_Product', 'exists'   => true],
+            ['type'     => 'model', 'name'     => 'catalog/nothing_to_see_here', 'expected' => 'Mage_Catalog_Model_Nothing_To_See_Here', 'exists'   => false],
+            ['type'     => 'helper', 'name'     => 'checkout/cart', 'expected' => 'Mage_Checkout_Helper_Cart', 'exists'   => true],
+            ['type'     => 'helper', 'name'     => 'checkout/stolen_creditcards', 'expected' => 'Mage_Checkout_Helper_Stolen_Creditcards', 'exists'   => false],
+            ['type'     => 'block', 'name'     => 'customer/account_dashboard', 'expected' => 'Mage_Customer_Block_Account_Dashboard', 'exists'   => true],
+            ['type'     => 'block', 'name'     => 'customer/my_code_snippets', 'expected' => 'Mage_Customer_Block_My_Code_Snippets', 'exists'   => false],
+        ];
     }
 }
diff --git a/tests/N98/Magento/Command/Developer/Ide/PhpStorm/MetaCommandTest.php b/tests/N98/Magento/Command/Developer/Ide/PhpStorm/MetaCommandTest.php
index fd94555e6..8a0fc404d 100644
--- a/tests/N98/Magento/Command/Developer/Ide/PhpStorm/MetaCommandTest.php
+++ b/tests/N98/Magento/Command/Developer/Ide/PhpStorm/MetaCommandTest.php
@@ -1,16 +1,19 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\Developer\Ide\PhpStorm;
 
 use N98\Magento\Command\TestCase;
 use Symfony\Component\Console\Tester\CommandTester;
 
-class MetaCommandTest extends TestCase
+final class MetaCommandTest extends TestCase
 {
     public function testExecute()
     {
         $application = $this->getApplication();
         $application->add(new MetaCommand());
+
         $command = $this->getApplication()->find('dev:ide:phpstorm:meta');
 
         $commandTester = new CommandTester($command);
@@ -20,22 +23,19 @@ public function testExecute()
 
         $fileContent = $commandTester->getDisplay(true);
 
-        self::assertStringContainsString('\'catalog\' => \Mage_Catalog_Helper_Data', $fileContent);
-        self::assertStringContainsString('\'core/config\' => \Mage_Core_Model_Config', $fileContent);
+        $this->assertStringContainsString('\'catalog\' => \Mage_Catalog_Helper_Data', $fileContent);
+        $this->assertStringContainsString('\'core/config\' => \Mage_Core_Model_Config', $fileContent);
 
         if (class_exists('\Mage_Core_Model_Resource_Config')) { // since magento 1.7
-            self::assertStringContainsString('\'core/config\' => \Mage_Core_Model_Resource_Config', $fileContent);
+            $this->assertStringContainsString('\'core/config\' => \Mage_Core_Model_Resource_Config', $fileContent);
         }
 
-        self::assertStringContainsString('\'wishlist\' => \Mage_Wishlist_Helper_Data', $fileContent);
+        $this->assertStringContainsString('\'wishlist\' => \Mage_Wishlist_Helper_Data', $fileContent);
 
         if (class_exists('\Mage_Core_Model_Resource_Helper_Mysql4')) {
-            self::assertStringContainsString('\'core\' => \Mage_Core_Model_Resource_Helper_Mysql4', $fileContent);
+            $this->assertStringContainsString('\'core\' => \Mage_Core_Model_Resource_Helper_Mysql4', $fileContent);
         }
 
-        self::assertStringNotContainsString(
-            '\'payment/paygate_request\' => \Mage_Payment_Model_Paygate_Request',
-            $fileContent,
-        );
+        $this->assertStringNotContainsString('\'payment/paygate_request\' => \Mage_Payment_Model_Paygate_Request', $fileContent);
     }
 }
diff --git a/tests/N98/Magento/Command/Developer/Log/LogCommand.php b/tests/N98/Magento/Command/Developer/Log/LogCommand.php
index 96ca77dbd..2d96d114d 100644
--- a/tests/N98/Magento/Command/Developer/Log/LogCommand.php
+++ b/tests/N98/Magento/Command/Developer/Log/LogCommand.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\Developer\Log;
 
 use N98\Magento\Command\TestCase;
@@ -12,6 +14,7 @@ public function testExecute()
         $application = $this->getApplication();
         $application->add(new LogCommand());
         $application->setAutoExit(false);
+
         $command = $this->getApplication()->find('dev:log');
 
         $commandTester = new CommandTester($command);
diff --git a/tests/N98/Magento/Command/Developer/MergeCssCommandTest.php b/tests/N98/Magento/Command/Developer/MergeCssCommandTest.php
index ccc3e5a31..9db57a0fa 100644
--- a/tests/N98/Magento/Command/Developer/MergeCssCommandTest.php
+++ b/tests/N98/Magento/Command/Developer/MergeCssCommandTest.php
@@ -1,30 +1,33 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\Developer;
 
 use N98\Magento\Command\TestCase;
 use Symfony\Component\Console\Tester\CommandTester;
 
-class MergeCssCommandTest extends TestCase
+final class MergeCssCommandTest extends TestCase
 {
     public function testExecute()
     {
         $application = $this->getApplication();
         $application->add(new MergeCssCommand());
         $application->setAutoExit(false);
+
         $command = $this->getApplication()->find('dev:merge-css');
 
         $commandTester = new CommandTester($command);
         $commandTester->execute(
             ['command'  => $command->getName(), '--on'     => true, 'store'    => 'admin'],
         );
-        self::assertMatchesRegularExpression('/CSS Merging enabled/', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression('/CSS Merging enabled/', $commandTester->getDisplay());
 
         $commandTester = new CommandTester($command);
         $commandTester->execute(
             ['command'  => $command->getName(), '--off'    => true, 'store'    => 'admin'],
         );
 
-        self::assertMatchesRegularExpression('/CSS Merging disabled/', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression('/CSS Merging disabled/', $commandTester->getDisplay());
     }
 }
diff --git a/tests/N98/Magento/Command/Developer/MergeJsCommandTest.php b/tests/N98/Magento/Command/Developer/MergeJsCommandTest.php
index d71a624cd..87add7a47 100644
--- a/tests/N98/Magento/Command/Developer/MergeJsCommandTest.php
+++ b/tests/N98/Magento/Command/Developer/MergeJsCommandTest.php
@@ -1,30 +1,33 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\Developer;
 
 use N98\Magento\Command\TestCase;
 use Symfony\Component\Console\Tester\CommandTester;
 
-class MergeJsCommandTest extends TestCase
+final class MergeJsCommandTest extends TestCase
 {
     public function testExecute()
     {
         $application = $this->getApplication();
         $application->add(new MergeJsCommand());
         $application->setAutoExit(false);
+
         $command = $this->getApplication()->find('dev:merge-js');
 
         $commandTester = new CommandTester($command);
         $commandTester->execute(
             ['command'  => $command->getName(), '--on'     => true, 'store'    => 'admin'],
         );
-        self::assertMatchesRegularExpression('/JS Merging enabled/', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression('/JS Merging enabled/', $commandTester->getDisplay());
 
         $commandTester = new CommandTester($command);
         $commandTester->execute(
             ['command'  => $command->getName(), '--off'    => true, 'store'    => 'admin'],
         );
 
-        self::assertMatchesRegularExpression('/JS Merging disabled/', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression('/JS Merging disabled/', $commandTester->getDisplay());
     }
 }
diff --git a/tests/N98/Magento/Command/Developer/Module/CreateCommandTest.php b/tests/N98/Magento/Command/Developer/Module/CreateCommandTest.php
index 950a03c42..3eb6d2170 100644
--- a/tests/N98/Magento/Command/Developer/Module/CreateCommandTest.php
+++ b/tests/N98/Magento/Command/Developer/Module/CreateCommandTest.php
@@ -1,17 +1,20 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\Developer\Module;
 
 use N98\Magento\Command\TestCase;
 use N98\Util\Filesystem;
 use Symfony\Component\Console\Tester\CommandTester;
 
-class CreateCommandTest extends TestCase
+final class CreateCommandTest extends TestCase
 {
     public function testExecute()
     {
         $application = $this->getApplication();
         $application->add(new ListCommand());
+
         $command = $this->getApplication()->find('dev:module:create');
 
         $root = getcwd();
@@ -28,16 +31,16 @@ public function testExecute()
             ['command'         => $command->getName(), '--add-all'       => true, '--add-setup'     => true, '--add-readme'    => true, '--add-composer'  => true, '--modman'        => true, '--description'   => 'Unit Test Description', '--author-name'   => 'Unit Test', '--author-email'  => 'n98-magerun@example.com', 'vendorNamespace' => 'N98Magerun', 'moduleName'      => 'UnitTest'],
         );
 
-        self::assertFileExists($root . '/N98Magerun_UnitTest/composer.json');
-        self::assertFileExists($root . '/N98Magerun_UnitTest/readme.md');
+        $this->assertFileExists($root . '/N98Magerun_UnitTest/composer.json');
+        $this->assertFileExists($root . '/N98Magerun_UnitTest/readme.md');
         $moduleBaseFolder = $root . '/N98Magerun_UnitTest/src/app/code/local/N98Magerun/UnitTest/';
-        self::assertFileExists($moduleBaseFolder . 'etc/config.xml');
-        self::assertFileExists($moduleBaseFolder . 'controllers');
-        self::assertFileExists($moduleBaseFolder . 'Block');
-        self::assertFileExists($moduleBaseFolder . 'Model');
-        self::assertFileExists($moduleBaseFolder . 'Helper');
-        self::assertFileExists($moduleBaseFolder . 'data/n98magerun_unittest_setup');
-        self::assertFileExists($moduleBaseFolder . 'sql/n98magerun_unittest_setup');
+        $this->assertFileExists($moduleBaseFolder . 'etc/config.xml');
+        $this->assertFileExists($moduleBaseFolder . 'controllers');
+        $this->assertFileExists($moduleBaseFolder . 'Block');
+        $this->assertFileExists($moduleBaseFolder . 'Model');
+        $this->assertFileExists($moduleBaseFolder . 'Helper');
+        $this->assertFileExists($moduleBaseFolder . 'data/n98magerun_unittest_setup');
+        $this->assertFileExists($moduleBaseFolder . 'sql/n98magerun_unittest_setup');
 
         // delete old module
         if (is_dir($root . '/N98Magerun_UnitTest')) {
diff --git a/tests/N98/Magento/Command/Developer/Module/Dependencies/FromCommandTest.php b/tests/N98/Magento/Command/Developer/Module/Dependencies/FromCommandTest.php
index 36788a55e..92bb3b4db 100644
--- a/tests/N98/Magento/Command/Developer/Module/Dependencies/FromCommandTest.php
+++ b/tests/N98/Magento/Command/Developer/Module/Dependencies/FromCommandTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\Developer\Module\Dependencies;
 
 use N98\Magento\Command\TestCase;
@@ -10,24 +12,28 @@
  *
  * @package N98\Magento\Command\Developer\Module\Dependencies
  */
-class FromCommandTest extends TestCase
+final class FromCommandTest extends TestCase
 {
-    public static function dataProviderTestExecute()
+    public static function dataProviderTestExecute(): \Iterator
     {
-        return ['Not existing module, no --all' => ['$moduleName'   => 'NotExistentModule', '$all'          => 0, '$expectations' => ['Module NotExistentModule was not found'], '$notContains'  => []], 'Not existing module, with --all' => ['$moduleName'   => 'NotExistentModule', '$all'          => 1, '$expectations' => ['Module NotExistentModule was not found'], '$notContains'  => []], 'Not existing module, with -a' => ['$moduleName'   => 'NotExistentModule', '$all'          => 2, '$expectations' => ['Module NotExistentModule was not found'], '$notContains'  => []], 'Mage_Admin module, no --all' => ['$moduleName'   => 'Mage_Admin', '$all'          => 0, '$expectations' => ['Mage_Adminhtml'], '$notContains'  => ['Mage_AdminNotification']], 'Mage_Admin module, with --all' => ['$moduleName'   => 'Mage_Admin', '$all'          => 1, '$expectations' => ['Mage_AdminNotification', 'Mage_Adminhtml'], '$notContains'  => ['Mage_Compiler', 'Mage_Customer']], 'Mage_Admin module, with -a' => ['$moduleName'   => 'Mage_Admin', '$all'          => 2, '$expectations' => ['Mage_AdminNotification', 'Mage_Adminhtml'], '$notContains'  => ['Mage_Compiler', 'Mage_Customer']]];
+        yield 'Not existing module, no --all' => ['$moduleName'   => 'NotExistentModule', '$all'          => 0, '$expectations' => ['Module NotExistentModule was not found'], '$notContains'  => []];
+        yield 'Not existing module, with --all' => ['$moduleName'   => 'NotExistentModule', '$all'          => 1, '$expectations' => ['Module NotExistentModule was not found'], '$notContains'  => []];
+        yield 'Not existing module, with -a' => ['$moduleName'   => 'NotExistentModule', '$all'          => 2, '$expectations' => ['Module NotExistentModule was not found'], '$notContains'  => []];
+        yield 'Mage_Admin module, no --all' => ['$moduleName'   => 'Mage_Admin', '$all'          => 0, '$expectations' => ['Mage_Adminhtml'], '$notContains'  => ['Mage_AdminNotification']];
+        yield 'Mage_Admin module, with --all' => ['$moduleName'   => 'Mage_Admin', '$all'          => 1, '$expectations' => ['Mage_AdminNotification', 'Mage_Adminhtml'], '$notContains'  => ['Mage_Compiler', 'Mage_Customer']];
+        yield 'Mage_Admin module, with -a' => ['$moduleName'   => 'Mage_Admin', '$all'          => 2, '$expectations' => ['Mage_AdminNotification', 'Mage_Adminhtml'], '$notContains'  => ['Mage_Compiler', 'Mage_Customer']];
     }
 
     /**
      * @dataProvider dataProviderTestExecute
      * @param string $moduleName
      * @param int $all
-     * @param array $contains
-     * @param array $notContains
      */
     public function testExecute($moduleName, $all, array $contains, array $notContains)
     {
         $application = $this->getApplication();
         $application->add(new FromCommand());
+
         $command = $this->getApplication()->find('dev:module:dependencies:from');
 
         $commandTester = new CommandTester($command);
@@ -45,11 +51,12 @@ public function testExecute($moduleName, $all, array $contains, array $notContai
         }
 
         $commandTester->execute($input);
-        foreach ($contains as $expectation) {
-            self::assertStringContainsString($expectation, $commandTester->getDisplay());
+        foreach ($contains as $contain) {
+            $this->assertStringContainsString($contain, $commandTester->getDisplay());
         }
-        foreach ($notContains as $expectation) {
-            self::assertStringNotContainsString($expectation, $commandTester->getDisplay());
+
+        foreach ($notContains as $notContain) {
+            $this->assertStringNotContainsString($notContain, $commandTester->getDisplay());
         }
     }
 }
diff --git a/tests/N98/Magento/Command/Developer/Module/Dependencies/OnCommandTest.php b/tests/N98/Magento/Command/Developer/Module/Dependencies/OnCommandTest.php
index 953360d8c..4491e59b9 100644
--- a/tests/N98/Magento/Command/Developer/Module/Dependencies/OnCommandTest.php
+++ b/tests/N98/Magento/Command/Developer/Module/Dependencies/OnCommandTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\Developer\Module\Dependencies;
 
 use N98\Magento\Command\TestCase;
@@ -10,38 +12,45 @@
  *
  * @package N98\Magento\Command\Developer\Module\Dependencies
  */
-class OnCommandTest extends TestCase
+final class OnCommandTest extends TestCase
 {
-    public static function dataProviderTestExecute()
+    public static function dataProviderTestExecute(): \Iterator
     {
-        return ['Not existing module, no --all' => ['$moduleName'   => 'NotExistentModule', '$all'          => 0, '$expectations' => ['Module NotExistentModule was not found'], '$notContains'  => []], 'Not existing module, with --all' => ['$moduleName'   => 'NotExistentModule', '$all'          => 1, '$expectations' => ['Module NotExistentModule was not found'], '$notContains'  => []], 'Not existing module, with -a' => ['$moduleName'   => 'NotExistentModule', '$all'          => 2, '$expectations' => ['Module NotExistentModule was not found'], '$notContains'  => []], 'Mage_Core module, no --all' => ['$moduleName'   => 'Mage_Core', '$all'          => 0, '$expectations' => ["Module Mage_Core doesn't have dependencies"], '$notContains'  => []], 'Mage_Core module, with --all' => ['$moduleName'   => 'Mage_Core', '$all'          => 1, '$expectations' => ["Module Mage_Core doesn't have dependencies"], '$notContains'  => []], 'Mage_Core module, with -a' => ['$moduleName'   => 'Mage_Core', '$all'          => 2, '$expectations' => ["Module Mage_Core doesn't have dependencies"], '$notContains'  => []], 'Mage_Customer module, no --all' => ['$moduleName'   => 'Mage_Customer', '$all'          => 0, '$expectations' => [
+        yield 'Not existing module, no --all' => ['$moduleName'   => 'NotExistentModule', '$all'          => 0, '$expectations' => ['Module NotExistentModule was not found'], '$notContains'  => []];
+        yield 'Not existing module, with --all' => ['$moduleName'   => 'NotExistentModule', '$all'          => 1, '$expectations' => ['Module NotExistentModule was not found'], '$notContains'  => []];
+        yield 'Not existing module, with -a' => ['$moduleName'   => 'NotExistentModule', '$all'          => 2, '$expectations' => ['Module NotExistentModule was not found'], '$notContains'  => []];
+        yield 'Mage_Core module, no --all' => ['$moduleName'   => 'Mage_Core', '$all'          => 0, '$expectations' => ["Module Mage_Core doesn't have dependencies"], '$notContains'  => []];
+        yield 'Mage_Core module, with --all' => ['$moduleName'   => 'Mage_Core', '$all'          => 1, '$expectations' => ["Module Mage_Core doesn't have dependencies"], '$notContains'  => []];
+        yield 'Mage_Core module, with -a' => ['$moduleName'   => 'Mage_Core', '$all'          => 2, '$expectations' => ["Module Mage_Core doesn't have dependencies"], '$notContains'  => []];
+        yield 'Mage_Customer module, no --all' => ['$moduleName'   => 'Mage_Customer', '$all'          => 0, '$expectations' => [
             'Mage_Dataflow',
             /*'Mage_Directory',*/
             'Mage_Eav',
-        ], '$notContains'  => ['Mage_Core']], 'Mage_Customer module, with --all' => ['$moduleName'   => 'Mage_Customer', '$all'          => 1, '$expectations' => [
+        ], '$notContains'  => ['Mage_Core']];
+        yield 'Mage_Customer module, with --all' => ['$moduleName'   => 'Mage_Customer', '$all'          => 1, '$expectations' => [
             'Mage_Core',
             'Mage_Dataflow',
             /*'Mage_Directory',*/
             'Mage_Eav',
-        ], '$notContains'  => []], 'Mage_Customer module, with -a' => ['$moduleName'   => 'Mage_Customer', '$all'          => 2, '$expectations' => [
+        ], '$notContains'  => []];
+        yield 'Mage_Customer module, with -a' => ['$moduleName'   => 'Mage_Customer', '$all'          => 2, '$expectations' => [
             'Mage_Core',
             'Mage_Dataflow',
             /*'Mage_Directory',*/
             'Mage_Eav',
-        ], '$notContains'  => []]];
+        ], '$notContains'  => []];
     }
 
     /**
      * @dataProvider dataProviderTestExecute
      * @param string $moduleName
      * @param int $all
-     * @param array $contains
-     * @param array $notContains
      */
     public function testExecute($moduleName, $all, array $contains, array $notContains)
     {
         $application = $this->getApplication();
         $application->add(new OnCommand());
+
         $command = $this->getApplication()->find('dev:module:dependencies:on');
 
         $commandTester = new CommandTester($command);
@@ -59,11 +68,12 @@ public function testExecute($moduleName, $all, array $contains, array $notContai
         }
 
         $commandTester->execute($input);
-        foreach ($contains as $expectation) {
-            self::assertStringContainsString($expectation, $commandTester->getDisplay());
+        foreach ($contains as $contain) {
+            $this->assertStringContainsString($contain, $commandTester->getDisplay());
         }
-        foreach ($notContains as $expectation) {
-            self::assertStringNotContainsString($expectation, $commandTester->getDisplay());
+
+        foreach ($notContains as $notContain) {
+            $this->assertStringNotContainsString($notContain, $commandTester->getDisplay());
         }
     }
 }
diff --git a/tests/N98/Magento/Command/Developer/Module/ListCommandTest.php b/tests/N98/Magento/Command/Developer/Module/ListCommandTest.php
index 81c9c5a5f..04f5e7f3d 100644
--- a/tests/N98/Magento/Command/Developer/Module/ListCommandTest.php
+++ b/tests/N98/Magento/Command/Developer/Module/ListCommandTest.php
@@ -1,16 +1,19 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\Developer\Module;
 
 use N98\Magento\Command\TestCase;
 use Symfony\Component\Console\Tester\CommandTester;
 
-class ListCommandTest extends TestCase
+final class ListCommandTest extends TestCase
 {
     public function testExecute()
     {
         $application = $this->getApplication();
         $application->add(new ListCommand());
+
         $command = $this->getApplication()->find('dev:module:list');
 
         $commandTester = new CommandTester($command);
@@ -18,6 +21,6 @@ public function testExecute()
             ['command' => $command->getName()],
         );
 
-        self::assertMatchesRegularExpression('/Mage_Core/', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression('/Mage_Core/', $commandTester->getDisplay());
     }
 }
diff --git a/tests/N98/Magento/Command/Developer/Module/Observer/ListCommandTest.php b/tests/N98/Magento/Command/Developer/Module/Observer/ListCommandTest.php
index ce8e9f684..7ed8c01e1 100644
--- a/tests/N98/Magento/Command/Developer/Module/Observer/ListCommandTest.php
+++ b/tests/N98/Magento/Command/Developer/Module/Observer/ListCommandTest.php
@@ -1,16 +1,19 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\Developer\Module\Observer;
 
 use N98\Magento\Command\TestCase;
 use Symfony\Component\Console\Tester\CommandTester;
 
-class ListCommandTest extends TestCase
+final class ListCommandTest extends TestCase
 {
     public function testExecute()
     {
         $application = $this->getApplication();
         $application->add(new ListCommand());
+
         $command = $this->getApplication()->find('dev:module:observer:list');
 
         $commandTester = new CommandTester($command);
@@ -18,6 +21,6 @@ public function testExecute()
             ['command' => $command->getName(), 'type'    => 'global'],
         );
 
-        self::assertStringContainsString('controller_front_init_routers', $commandTester->getDisplay());
+        $this->assertStringContainsString('controller_front_init_routers', $commandTester->getDisplay());
     }
 }
diff --git a/tests/N98/Magento/Command/Developer/Module/Rewrite/ClassExistsCheckerTest.php b/tests/N98/Magento/Command/Developer/Module/Rewrite/ClassExistsCheckerTest.php
index 60dd57b67..34eeacc22 100644
--- a/tests/N98/Magento/Command/Developer/Module/Rewrite/ClassExistsCheckerTest.php
+++ b/tests/N98/Magento/Command/Developer/Module/Rewrite/ClassExistsCheckerTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 /**
  * this file is part of magerun
  *
@@ -21,7 +23,7 @@
  *
  * @covers \N98\Magento\Command\Developer\Module\Rewrite\ClassExistsChecker
  */
-class ClassExistsCheckerTest extends TestCase
+final class ClassExistsCheckerTest extends TestCase
 {
     /**
      * @var array
@@ -34,42 +36,30 @@ protected function tearDown(): void
         parent::tearDown();
     }
 
-    /**
-     * @test
-     */
-    public function creation()
+    public function testCreation()
     {
         $checker = new ClassExistsChecker('Le_Foo_Le_Bar_Nexiste_Pas');
-        self::assertInstanceOf(__NAMESPACE__ . '\ClassExistsChecker', $checker);
+        $this->assertInstanceOf(__NAMESPACE__ . '\ClassExistsChecker', $checker);
 
         $checker = ClassExistsChecker::create('Le_Foo_Le_Bar_Nexiste_Pas');
-        self::assertInstanceOf(__NAMESPACE__ . '\ClassExistsChecker', $checker);
+        $this->assertInstanceOf(__NAMESPACE__ . '\ClassExistsChecker', $checker);
     }
 
-    /**
-     * @test
-     */
-    public function existingClass()
+    public function testExistingClass()
     {
-        self::assertTrue(ClassExistsChecker::create(IteratorIterator::class)->existsExtendsSafe());
+        $this->assertTrue(ClassExistsChecker::create(IteratorIterator::class)->existsExtendsSafe());
     }
 
-    /**
-     * @test
-     */
-    public function nonExistingClass()
+    public function testNonExistingClass()
     {
-        self::assertFalse(ClassExistsChecker::create('asdfu8jq23nklr08asASDF0oaosdufhoanl')->existsExtendsSafe());
+        $this->assertFalse(ClassExistsChecker::create('asdfu8jq23nklr08asASDF0oaosdufhoanl')->existsExtendsSafe());
     }
 
-    /**
-     * @test
-     */
-    public function throwingAnExceptionWhileIncluding()
+    public function testThrowingAnExceptionWhileIncluding()
     {
         // similar to Varien_Autoload
         $innerException = null;
-        $autoload = $this->create(function ($className) use (&$innerException) {
+        $autoloadHandler = $this->create(function ($className) use (&$innerException): void {
             $innerException = new BadMethodCallException('exception in include simulation for ' . $className);
             throw $innerException;
         });
@@ -77,54 +67,51 @@ public function throwingAnExceptionWhileIncluding()
         try {
             $className = 'Le_Foo_Le_Bar_Nexiste_Pas';
             ClassExistsChecker::create($className)->existsExtendsSafe();
-            $autoload->reset();
+            $autoloadHandler->reset();
             self::fail('An expected Exception has not been thrown');
-        } catch (Exception $ex) {
-            $autoload->reset();
-            self::assertInstanceOf(__NAMESPACE__ . '\ClassExistsThrownException', $ex);
-            isset($innerException) && self::assertInstanceOf(get_class($innerException), $ex->getPrevious());
-            self::assertSame($innerException, $ex->getPrevious());
+        } catch (Exception $exception) {
+            $autoloadHandler->reset();
+            $this->assertInstanceOf(__NAMESPACE__ . '\ClassExistsThrownException', $exception);
+            if (isset($innerException)) {
+                $this->assertInstanceOf(get_class($innerException), $exception->getPrevious());
+            }
+
+            $this->assertSame($innerException, $exception->getPrevious());
         }
     }
 
     /**
-     * @return array
+     * @return \Iterator<(int | string), mixed>
      * @see preventingFatalOnNonExistingBaseClass
      */
-    public function provideClassNames()
+    public function provideClassNames(): \Iterator
     {
-        return [
-            ['Le_Foo_Le_Bar'],
-            # extends from a non-existing file of that base-class
-            ['Le_Foo_Le_Bar_R1'],
-        ];
+        yield ['Le_Foo_Le_Bar'];
+        # extends from a non-existing file of that base-class
+        yield ['Le_Foo_Le_Bar_R1'];
     }
 
     /**
-     * @test
      * @dataProvider provideClassNames
      * @param string $className
      */
-    public function preventingFatalOnNonExistingBaseClass($className)
+    public function testPreventingFatalOnNonExistingBaseClass($className)
     {
-        $autoload = $this->create($this->getAutoloader());
+        $autoloadHandler = $this->create($this->getAutoloader());
         $restore = $this->noErrorExceptions();
         try {
             $actual = ClassExistsChecker::create($className)->existsExtendsSafe();
             $restore();
-            $autoload->reset();
-            self::assertFalse($actual);
-        } catch (Exception $ex) {
+            $autoloadHandler->reset();
+            $this->assertFalse($actual);
+        } catch (Exception $exception) {
             $restore();
-            $autoload->reset();
+            $autoloadHandler->reset();
             self::fail('An exception has been thrown');
         }
     }
 
-    /**
-     * @test
-     */
-    public function warningTriggeringExpectedBehaviour()
+    public function testWarningTriggeringExpectedBehaviour()
     {
         $this->markTestSkipped('Maybe not compatible with PHP 8.1 anymore. Has to be checked again.');
         $undef_var = null;
@@ -136,43 +123,43 @@ public function warningTriggeringExpectedBehaviour()
         $canary = error_get_last();
 
         // precondition is that there was no error yet
-        self::assertNotNull($canary, 'precondition not met');
+        $this->assertNotNull($canary, 'precondition not met');
 
         // precondition of the error reporting level
         $reporting = error_reporting();
         // 22527 - E_ALL & ~E_DEPRECATED & ~E_STRICT (PHP 5.6)
         // 32767 - E_ALL (Travis PHP 5.3, PHP 5.4)
         $knownErrorLevels = ['E_ALL & ~E_DEPRECATED & ~E_STRICT (Deb Sury 5.6)' => 22527, 'E_ALL (Travis PHP 5.3, 5.4, 5.5)'                 => 32767];
-        self::assertContains($reporting, $knownErrorLevels, "error reporting as of $reporting");
+        $this->assertContains($reporting, $knownErrorLevels, 'error reporting as of ' . $reporting);
 
         // by default the class must be loaded with a different autoloader
-        self::assertFalse(class_exists('Le_Foo_Le_Bar_Fine'));
+        $this->assertFalse(class_exists('Le_Foo_Le_Bar_Fine'));
 
         // post-condition is that there was no error yet
-        self::assertSame($canary, error_get_last());
+        $this->assertSame($canary, error_get_last());
 
         // should not trigger an error if the class exists
-        $autoload = $this->create($this->getAutoloader());
-        self::assertTrue(class_exists('Le_Foo_Le_Bar_Fine'));
-        self::assertSame($canary, error_get_last());
+        $this->create($this->getAutoloader());
+        $this->assertTrue(class_exists('Le_Foo_Le_Bar_Fine'));
+        $this->assertSame($canary, error_get_last());
 
         // should trigger a warning if the class does not exists as file on disk per auto-loading
         $restore = $this->noErrorExceptions();
         $actual = class_exists('Le_Foo_Le_Bar_Nexiste_Pas');
         $restore();
 
-        self::assertFalse($actual);
+        $this->assertFalse($actual);
         $lastError = error_get_last();
         if ($canary === $lastError) {
             self::markTestIncomplete('System does not triggers the expected warning on include');
         }
 
-        self::assertNotSame($canary, $lastError);
-        self::assertArrayHasKey('type', $lastError);
-        self::assertSame(2, $lastError['type']);
-        self::assertArrayHasKey('message', $lastError);
+        $this->assertNotSame($canary, $lastError);
+        $this->assertArrayHasKey('type', $lastError);
+        $this->assertSame(2, $lastError['type']);
+        $this->assertArrayHasKey('message', $lastError);
         $pattern = '~include\(\): Failed opening \'.*Rewrite/fixture/Le_Foo_Le_Bar_Nexiste_Pas\.php\' for inclusion ~';
-        self::assertMatchesRegularExpression($pattern, $lastError['message']);
+        $this->assertMatchesRegularExpression($pattern, $lastError['message']);
     }
 
     /**
@@ -183,9 +170,10 @@ public function warningTriggeringExpectedBehaviour()
     private function getAutoloader()
     {
         return function ($className) {
-            if (!preg_match('~^(Le_Foo_Le_Bar)~', $className)) {
+            if (in_array(preg_match('~^(Le_Foo_Le_Bar)~', $className), [0, false], true)) {
                 return false;
             }
+
             $file = __DIR__ . '/fixture/' . $className . '.php';
 
             return include $file;
@@ -207,7 +195,7 @@ private function noErrorExceptions($includeIni = true)
         $logErrorsOrig = ini_get('log_errors');
         $includeIni && ini_set('log_errors', false);
 
-        $restore = function () use ($displayErrorsOrig, $logErrorsOrig) {
+        $restore = function () use ($displayErrorsOrig, $logErrorsOrig): void {
             ini_set('display_errors', $displayErrorsOrig);
             ini_set('log_errors', $logErrorsOrig);
         };
@@ -222,14 +210,13 @@ private function noErrorExceptions($includeIni = true)
      * after test is over
      *
      * @param $callback
-     * @param null $flags
      * @return AutoloadHandler
      */
     private function create($callback, $flags = null)
     {
-        $handler = AutoloadHandler::create($callback, $flags);
-        $this->cleanup[] = $handler->getCleanupCallback();
-        return $handler;
+        $autoloadHandler = AutoloadHandler::create($callback, $flags);
+        $this->cleanup[] = $autoloadHandler->getCleanupCallback();
+        return $autoloadHandler;
     }
 
     private function cleanup()
diff --git a/tests/N98/Magento/Command/Developer/Module/Rewrite/ConflictsCommandTest.php b/tests/N98/Magento/Command/Developer/Module/Rewrite/ConflictsCommandTest.php
index 4e359714d..311a5a802 100644
--- a/tests/N98/Magento/Command/Developer/Module/Rewrite/ConflictsCommandTest.php
+++ b/tests/N98/Magento/Command/Developer/Module/Rewrite/ConflictsCommandTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\Developer\Module\Rewrite;
 
 use N98\Magento\Command\TestCase;
@@ -11,12 +13,13 @@
  * @TODO Check with simulated conflict
  * @package N98\Magento\Command\Developer\Module\Rewrite
  */
-class ConflictsCommandTest extends TestCase
+final class ConflictsCommandTest extends TestCase
 {
     public function testExecute()
     {
         $application = $this->getApplication();
         $application->add(new ConflictsCommand());
+
         $command = $this->getApplication()->find('dev:module:rewrite:conflicts');
 
         /**
@@ -26,7 +29,7 @@ public function testExecute()
         $commandTester->execute(
             ['command' => $command->getName()],
         );
-        self::assertStringContainsString('No rewrite conflicts were found', $commandTester->getDisplay());
+        $this->assertStringContainsString('No rewrite conflicts were found', $commandTester->getDisplay());
 
         /**
          * Junit Log without any output
@@ -35,9 +38,9 @@ public function testExecute()
         $result = $commandTester->execute(
             ['command'     => $command->getName(), '--log-junit' => '_output.xml'],
         );
-        self::assertEquals(0, $result);
-        self::assertEquals('', $commandTester->getDisplay());
-        self::assertFileExists('_output.xml');
+        $this->assertSame(0, $result);
+        $this->assertSame('', $commandTester->getDisplay());
+        $this->assertFileExists('_output.xml');
         @unlink('_output.xml');
     }
 
@@ -47,11 +50,11 @@ public function testExecute()
     public function testExecuteConflict()
     {
         $rewrites = ['blocks' => ['n98/mock_conflict' => ['Mage_Customer_Block_Account', 'Mage_Tag_Block_All']]];
-        $command = $this->getCommandWithMockLoadRewrites($rewrites);
-        $commandTester = new CommandTester($command);
-        $result = $commandTester->execute(['command' => $command->getName()]);
-        self::assertNotEquals(0, $result);
-        self::assertStringContainsString('1 conflict was found', $commandTester->getDisplay());
+        $conflictsCommand = $this->getCommandWithMockLoadRewrites($rewrites);
+        $commandTester = new CommandTester($conflictsCommand);
+        $result = $commandTester->execute(['command' => $conflictsCommand->getName()]);
+        $this->assertNotSame(0, $result);
+        $this->assertStringContainsString('1 conflict was found', $commandTester->getDisplay());
     }
 
     /**
@@ -62,18 +65,17 @@ public function testExecuteConflict()
     public function testExecuteConflictFalsePositive()
     {
         $rewrites = ['blocks' => ['n98/mock_conflict' => ['Mage_Catalog_Block_Product_Price', 'Mage_Bundle_Block_Catalog_Product_Price']]];
-        $command = $this->getCommandWithMockLoadRewrites($rewrites);
-        $commandTester = new CommandTester($command);
-        $result = $commandTester->execute(['command' => $command->getName()]);
-        self::assertEquals(0, $result);
-        self::assertStringContainsString('No rewrite conflicts were found', $commandTester->getDisplay());
+        $conflictsCommand = $this->getCommandWithMockLoadRewrites($rewrites);
+        $commandTester = new CommandTester($conflictsCommand);
+        $result = $commandTester->execute(['command' => $conflictsCommand->getName()]);
+        $this->assertSame(0, $result);
+        $this->assertStringContainsString('No rewrite conflicts were found', $commandTester->getDisplay());
     }
 
     /**
      * Mock the ConflictsCommand and change the return value of loadRewrites()
      * to the given argument
      *
-     * @param  array            $return
      * @return ConflictsCommand
      */
     private function getCommandWithMockLoadRewrites(array $return)
diff --git a/tests/N98/Magento/Command/Developer/Module/Rewrite/fixture/Le_Foo_Le_Bar.php b/tests/N98/Magento/Command/Developer/Module/Rewrite/fixture/Le_Foo_Le_Bar.php
index c372c57e5..d8ddc95d2 100644
--- a/tests/N98/Magento/Command/Developer/Module/Rewrite/fixture/Le_Foo_Le_Bar.php
+++ b/tests/N98/Magento/Command/Developer/Module/Rewrite/fixture/Le_Foo_Le_Bar.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 /**
  * this file is part of magerun
  *
@@ -7,5 +9,4 @@
  *
  * Class definition that will cause a warning when the non-existing parent-class is included from the same directory
  */
-
 class Le_Foo_Le_Bar extends Le_Foo_Le_Bar_Nexiste_Pas {}
diff --git a/tests/N98/Magento/Command/Developer/Module/Rewrite/fixture/Le_Foo_Le_Bar_Fine.php b/tests/N98/Magento/Command/Developer/Module/Rewrite/fixture/Le_Foo_Le_Bar_Fine.php
index 0dd403428..0c9924cd4 100644
--- a/tests/N98/Magento/Command/Developer/Module/Rewrite/fixture/Le_Foo_Le_Bar_Fine.php
+++ b/tests/N98/Magento/Command/Developer/Module/Rewrite/fixture/Le_Foo_Le_Bar_Fine.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 /**
  * this file is part of magerun
  *
@@ -7,5 +9,4 @@
  *
  * Class definition that just works when it is included from the same directory
  */
-
 class Le_Foo_Le_Bar_Fine {}
diff --git a/tests/N98/Magento/Command/Developer/Module/Rewrite/fixture/Le_Foo_Le_Bar_R1.php b/tests/N98/Magento/Command/Developer/Module/Rewrite/fixture/Le_Foo_Le_Bar_R1.php
index 8db95b483..060bad014 100644
--- a/tests/N98/Magento/Command/Developer/Module/Rewrite/fixture/Le_Foo_Le_Bar_R1.php
+++ b/tests/N98/Magento/Command/Developer/Module/Rewrite/fixture/Le_Foo_Le_Bar_R1.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 /**
  * this file is part of magerun
  *
@@ -7,7 +9,6 @@
  *
  * Faux conditional class definition as this is common with module checks
  */
-
 if (true) {
     class Le_Foo_Le_Bar_R1 extends Le_Foo_Le_Bar_R2 {}
 } else {
diff --git a/tests/N98/Magento/Command/Developer/Module/Rewrite/fixture/Le_Foo_Le_Bar_R2.php b/tests/N98/Magento/Command/Developer/Module/Rewrite/fixture/Le_Foo_Le_Bar_R2.php
index 02f1b7283..402229b54 100644
--- a/tests/N98/Magento/Command/Developer/Module/Rewrite/fixture/Le_Foo_Le_Bar_R2.php
+++ b/tests/N98/Magento/Command/Developer/Module/Rewrite/fixture/Le_Foo_Le_Bar_R2.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 /**
  * this file is part of magerun
  *
@@ -7,5 +9,4 @@
  *
  * Class definition that will cause a warning when the non-existing parent-class is included from the same directory
  */
-
 class Le_Foo_Le_Bar_R2 extends Le_Foo_Le_Bar_Nexiste_Pas {}
diff --git a/tests/N98/Magento/Command/Developer/Module/UpdateCommandTest.php b/tests/N98/Magento/Command/Developer/Module/UpdateCommandTest.php
index 128a49a02..aa082f914 100644
--- a/tests/N98/Magento/Command/Developer/Module/UpdateCommandTest.php
+++ b/tests/N98/Magento/Command/Developer/Module/UpdateCommandTest.php
@@ -1,12 +1,14 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\Developer\Module;
 
 use N98\Magento\Command\TestCase;
 use N98\Util\Filesystem;
 use Symfony\Component\Console\Tester\CommandTester;
 
-class UpdateCommandTest extends TestCase
+final class UpdateCommandTest extends TestCase
 {
     /**
      * @doesNotPerformAssertions
@@ -16,9 +18,11 @@ public function testExecute()
         $this->markTestIncomplete('Find a replacement for missing setInputStream of question helper');
         $application = $this->getApplication();
         $application->add(new ListCommand());
+
         $createCommand = $this->getApplication()->find('dev:module:create');
         $updateCommand = $this->getApplication()->find('dev:module:update');
         $updateCommand->setTestMode(true);
+
         $root = getcwd();
         $this->_deleteOldModule($root);
 
@@ -48,7 +52,7 @@ public function testExecute()
      * @param $root
      * @return bool|Filesystem
      */
-    protected function _deleteOldModule($root)
+    private function _deleteOldModule($root)
     {
         // delete old module
         $filesystem = false;
@@ -58,13 +62,14 @@ protected function _deleteOldModule($root)
             $filesystem->recursiveRemoveDirectory($root . '/N98Magerun_UnitTest');
             clearstatcache();
         }
+
         return $filesystem;
     }
 
-    protected function getInputStream($input)
+    private function getInputStream($input)
     {
         $stream = fopen('php://memory', 'rb+', false);
-        fputs($stream, $input);
+        fwrite($stream, $input);
 
         rewind($stream);
         return $stream;
@@ -74,7 +79,7 @@ protected function getInputStream($input)
      * @param $moduleBaseFolder
      * @return string
      */
-    protected function _getConfigXmlContents($moduleBaseFolder)
+    private function _getConfigXmlContents($moduleBaseFolder)
     {
         return file_get_contents($moduleBaseFolder . 'etc/config.xml');
     }
@@ -84,16 +89,16 @@ protected function _getConfigXmlContents($moduleBaseFolder)
      * @param $updateCommand
      * @param $moduleBaseFolder
      */
-    protected function _setVersionOptionTest($commandTester, $updateCommand, $moduleBaseFolder)
+    private function _setVersionOptionTest($commandTester, $updateCommand, $moduleBaseFolder)
     {
         $commandTester->execute(
             ['command'         => $updateCommand->getName(), '--set-version'   => true, 'vendorNamespace' => 'N98Magerun', 'moduleName'      => 'UnitTest'],
         );
 
-        self::assertFileExists($moduleBaseFolder . 'etc/config.xml');
+        $this->assertFileExists($moduleBaseFolder . 'etc/config.xml');
 
         $configXmlContent = $this->_getConfigXmlContents($moduleBaseFolder);
-        self::assertStringContainsString('<version>2.0.0</version>', $configXmlContent);
+        $this->assertStringContainsString('<version>2.0.0</version>', $configXmlContent);
     }
 
     /**
@@ -103,7 +108,7 @@ protected function _setVersionOptionTest($commandTester, $updateCommand, $module
      * @param $moduleBaseFolder
      * @return string
      */
-    protected function _addResourceModelOptionTest($dialog, $commandTester, $updateCommand, $moduleBaseFolder)
+    private function _addResourceModelOptionTest($dialog, $commandTester, $updateCommand, $moduleBaseFolder)
     {
         $dialog->setInputStream($this->getInputStream("y\nentity1\nentity1table\nentity2\nentity2table\n\n"));
         $commandTester->execute(
@@ -111,14 +116,14 @@ protected function _addResourceModelOptionTest($dialog, $commandTester, $updateC
         );
 
         $configXmlContent = $this->_getConfigXmlContents($moduleBaseFolder);
-        self::assertStringContainsString('<n98magerun_unittest_resource>', $configXmlContent);
-        self::assertStringContainsString('<deprecatedNode>n98magerun_unittest_resource_eav_mysql4</deprecatedNode>', $configXmlContent);
-        self::assertStringContainsString('<class>N98Magerun_UnitTest_Model_Resource</class>', $configXmlContent);
-        self::assertStringContainsString('<entities>', $configXmlContent);
-        self::assertStringContainsString('<entity1>', $configXmlContent);
-        self::assertStringContainsString('<table>entity1table</table>', $configXmlContent);
-        self::assertStringContainsString('<entity2>', $configXmlContent);
-        self::assertStringContainsString('<table>entity2table</table>', $configXmlContent);
+        $this->assertStringContainsString('<n98magerun_unittest_resource>', $configXmlContent);
+        $this->assertStringContainsString('<deprecatedNode>n98magerun_unittest_resource_eav_mysql4</deprecatedNode>', $configXmlContent);
+        $this->assertStringContainsString('<class>N98Magerun_UnitTest_Model_Resource</class>', $configXmlContent);
+        $this->assertStringContainsString('<entities>', $configXmlContent);
+        $this->assertStringContainsString('<entity1>', $configXmlContent);
+        $this->assertStringContainsString('<table>entity1table</table>', $configXmlContent);
+        $this->assertStringContainsString('<entity2>', $configXmlContent);
+        $this->assertStringContainsString('<table>entity2table</table>', $configXmlContent);
     }
 
     /**
@@ -127,7 +132,7 @@ protected function _addResourceModelOptionTest($dialog, $commandTester, $updateC
      * @param $updateCommand
      * @param $moduleBaseFolder
      */
-    protected function _addRoutersOptionTest($dialog, $commandTester, $updateCommand, $moduleBaseFolder)
+    private function _addRoutersOptionTest($dialog, $commandTester, $updateCommand, $moduleBaseFolder)
     {
         $dialog->setInputStream($this->getInputStream("admin\nstandard\nn98magerun\n"));
         $commandTester->execute(
@@ -135,13 +140,13 @@ protected function _addRoutersOptionTest($dialog, $commandTester, $updateCommand
         );
 
         $configXmlContent = $this->_getConfigXmlContents($moduleBaseFolder);
-        self::assertStringContainsString('<admin>', $configXmlContent);
-        self::assertStringContainsString('<routers>', $configXmlContent);
-        self::assertStringContainsString('<n98magerun_unittest>', $configXmlContent);
-        self::assertStringContainsString('<args>', $configXmlContent);
-        self::assertStringContainsString('<use>standard</use>', $configXmlContent);
-        self::assertStringContainsString('<module>n98magerun_unittest</module>', $configXmlContent);
-        self::assertStringContainsString('<frontName>n98magerun</frontName>', $configXmlContent);
+        $this->assertStringContainsString('<admin>', $configXmlContent);
+        $this->assertStringContainsString('<routers>', $configXmlContent);
+        $this->assertStringContainsString('<n98magerun_unittest>', $configXmlContent);
+        $this->assertStringContainsString('<args>', $configXmlContent);
+        $this->assertStringContainsString('<use>standard</use>', $configXmlContent);
+        $this->assertStringContainsString('<module>n98magerun_unittest</module>', $configXmlContent);
+        $this->assertStringContainsString('<frontName>n98magerun</frontName>', $configXmlContent);
     }
 
     /**
@@ -150,18 +155,18 @@ protected function _addRoutersOptionTest($dialog, $commandTester, $updateCommand
      * @param $updateCommand
      * @param $moduleBaseFolder
      */
-    protected function _addEventsOptionTest($dialog, $commandTester, $updateCommand, $moduleBaseFolder)
+    private function _addEventsOptionTest($dialog, $commandTester, $updateCommand, $moduleBaseFolder)
     {
         $dialog->setInputStream($this->getInputStream("frontend\ncontroller_action_postdispatch\nn98mageruntest_observer\nn98magerun_unittest/observer\ncontrollerActionPostdispatch"));
         $commandTester->execute(
             ['command'         => $updateCommand->getName(), '--add-events'    => true, 'vendorNamespace' => 'N98Magerun', 'moduleName'      => 'UnitTest'],
         );
         $configXmlContent = $this->_getConfigXmlContents($moduleBaseFolder);
-        self::assertStringContainsString('<frontend>', $configXmlContent);
-        self::assertStringContainsString('<events>', $configXmlContent);
-        self::assertStringContainsString('<n98mageruntest_observer>', $configXmlContent);
-        self::assertStringContainsString('<class>n98magerun_unittest/observer</class>', $configXmlContent);
-        self::assertStringContainsString('<method>controllerActionPostdispatch</method>', $configXmlContent);
+        $this->assertStringContainsString('<frontend>', $configXmlContent);
+        $this->assertStringContainsString('<events>', $configXmlContent);
+        $this->assertStringContainsString('<n98mageruntest_observer>', $configXmlContent);
+        $this->assertStringContainsString('<class>n98magerun_unittest/observer</class>', $configXmlContent);
+        $this->assertStringContainsString('<method>controllerActionPostdispatch</method>', $configXmlContent);
     }
 
     /**
@@ -170,18 +175,18 @@ protected function _addEventsOptionTest($dialog, $commandTester, $updateCommand,
      * @param $updateCommand
      * @param $moduleBaseFolder
      */
-    protected function _addLayoutUpdatesOptionTest($dialog, $commandTester, $updateCommand, $moduleBaseFolder)
+    private function _addLayoutUpdatesOptionTest($dialog, $commandTester, $updateCommand, $moduleBaseFolder)
     {
         $dialog->setInputStream($this->getInputStream("adminhtml\nn98magerun_unittest\nn98magerun_unittest.xml"));
         $commandTester->execute(
             ['command'              => $updateCommand->getName(), '--add-layout-updates' => true, 'vendorNamespace'      => 'N98Magerun', 'moduleName'           => 'UnitTest'],
         );
         $configXmlContent = $this->_getConfigXmlContents($moduleBaseFolder);
-        self::assertStringContainsString('<adminhtml>', $configXmlContent);
-        self::assertStringContainsString('<layout>', $configXmlContent);
-        self::assertStringContainsString('<updates>', $configXmlContent);
-        self::assertStringContainsString('<n98magerun_unittest>', $configXmlContent);
-        self::assertStringContainsString('<file>n98magerun_unittest.xml</file>', $configXmlContent);
+        $this->assertStringContainsString('<adminhtml>', $configXmlContent);
+        $this->assertStringContainsString('<layout>', $configXmlContent);
+        $this->assertStringContainsString('<updates>', $configXmlContent);
+        $this->assertStringContainsString('<n98magerun_unittest>', $configXmlContent);
+        $this->assertStringContainsString('<file>n98magerun_unittest.xml</file>', $configXmlContent);
     }
 
     /**
@@ -190,19 +195,19 @@ protected function _addLayoutUpdatesOptionTest($dialog, $commandTester, $updateC
      * @param $updateCommand
      * @param $moduleBaseFolder
      */
-    protected function _addTranslateOptionTest($dialog, $commandTester, $updateCommand, $moduleBaseFolder)
+    private function _addTranslateOptionTest($dialog, $commandTester, $updateCommand, $moduleBaseFolder)
     {
         $dialog->setInputStream($this->getInputStream("adminhtml\nN98magerun_UnitTest.csv"));
         $commandTester->execute(
             ['command'         => $updateCommand->getName(), '--add-translate' => true, 'vendorNamespace' => 'N98Magerun', 'moduleName'      => 'UnitTest'],
         );
         $configXmlContent = $this->_getConfigXmlContents($moduleBaseFolder);
-        self::assertStringContainsString('<adminhtml>', $configXmlContent);
-        self::assertStringContainsString('<translate>', $configXmlContent);
-        self::assertStringContainsString('<modules>', $configXmlContent);
-        self::assertStringContainsString('<N98Magerun_UnitTest>', $configXmlContent);
-        self::assertStringContainsString('<files>', $configXmlContent);
-        self::assertStringContainsString('<default>N98magerun_UnitTest.csv</default>', $configXmlContent);
+        $this->assertStringContainsString('<adminhtml>', $configXmlContent);
+        $this->assertStringContainsString('<translate>', $configXmlContent);
+        $this->assertStringContainsString('<modules>', $configXmlContent);
+        $this->assertStringContainsString('<N98Magerun_UnitTest>', $configXmlContent);
+        $this->assertStringContainsString('<files>', $configXmlContent);
+        $this->assertStringContainsString('<default>N98magerun_UnitTest.csv</default>', $configXmlContent);
     }
 
     /**
@@ -211,16 +216,16 @@ protected function _addTranslateOptionTest($dialog, $commandTester, $updateComma
      * @param $updateCommand
      * @param $moduleBaseFolder
      */
-    protected function _addDefaultOptionTest($dialog, $commandTester, $updateCommand, $moduleBaseFolder)
+    private function _addDefaultOptionTest($dialog, $commandTester, $updateCommand, $moduleBaseFolder)
     {
         $dialog->setInputStream($this->getInputStream("sectiontest\ngrouptest\nfieldname\nfieldvalue"));
         $commandTester->execute(
             ['command'         => $updateCommand->getName(), '--add-default'   => true, 'vendorNamespace' => 'N98Magerun', 'moduleName'      => 'UnitTest'],
         );
         $configXmlContent = $this->_getConfigXmlContents($moduleBaseFolder);
-        self::assertStringContainsString('<default>', $configXmlContent);
-        self::assertStringContainsString('<sectiontest>', $configXmlContent);
-        self::assertStringContainsString('<grouptest>', $configXmlContent);
-        self::assertStringContainsString('<fieldname>fieldvalue</fieldname>', $configXmlContent);
+        $this->assertStringContainsString('<default>', $configXmlContent);
+        $this->assertStringContainsString('<sectiontest>', $configXmlContent);
+        $this->assertStringContainsString('<grouptest>', $configXmlContent);
+        $this->assertStringContainsString('<fieldname>fieldvalue</fieldname>', $configXmlContent);
     }
 }
diff --git a/tests/N98/Magento/Command/Developer/ProfilerCommandTest.php b/tests/N98/Magento/Command/Developer/ProfilerCommandTest.php
index 2397f3c7e..d8edad711 100644
--- a/tests/N98/Magento/Command/Developer/ProfilerCommandTest.php
+++ b/tests/N98/Magento/Command/Developer/ProfilerCommandTest.php
@@ -1,30 +1,33 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\Developer;
 
 use N98\Magento\Command\TestCase;
 use Symfony\Component\Console\Tester\CommandTester;
 
-class ProfilerCommandTest extends TestCase
+final class ProfilerCommandTest extends TestCase
 {
     public function testExecute()
     {
         $application = $this->getApplication();
         $application->add(new ProfilerCommand());
         $application->setAutoExit(false);
+
         $command = $this->getApplication()->find('dev:profiler');
 
         $commandTester = new CommandTester($command);
         $commandTester->execute(
             ['command'  => $command->getName(), '--global' => true, '--on'     => true],
         );
-        self::assertMatchesRegularExpression('/Profiler enabled/', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression('/Profiler enabled/', $commandTester->getDisplay());
 
         $commandTester = new CommandTester($command);
         $commandTester->execute(
             ['command'  => $command->getName(), '--global' => true, '--off'    => true],
         );
 
-        self::assertMatchesRegularExpression('/Profiler disabled/', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression('/Profiler disabled/', $commandTester->getDisplay());
     }
 }
diff --git a/tests/N98/Magento/Command/Developer/Setup/Script/AttributeCommandTest.php b/tests/N98/Magento/Command/Developer/Setup/Script/AttributeCommandTest.php
index d1d23513f..735b75639 100644
--- a/tests/N98/Magento/Command/Developer/Setup/Script/AttributeCommandTest.php
+++ b/tests/N98/Magento/Command/Developer/Setup/Script/AttributeCommandTest.php
@@ -1,27 +1,27 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\Developer\Setup\Script;
 
 use N98\Magento\Command\TestCase;
 use Symfony\Component\Console\Tester\CommandTester;
 
-class AttributeCommandTest extends TestCase
+final class AttributeCommandTest extends TestCase
 {
     public function testExecute()
     {
         $application = $this->getApplication();
         $application->add(new AttributeCommand());
         $application->setAutoExit(false);
+
         $command = $this->getApplication()->find('dev:setup:script:attribute');
 
         $commandTester = new CommandTester($command);
         $commandTester->execute(
             ['command'       => $command->getName(), 'entityType'    => 'catalog_product', 'attributeCode' => 'sku'],
         );
-        self::assertStringContainsString("'type' => 'static',", $commandTester->getDisplay());
-        self::assertStringContainsString(
-            "Mage::getModel('eav/entity_attribute')->loadByCode('catalog_product', 'sku');",
-            $commandTester->getDisplay(),
-        );
+        $this->assertStringContainsString("'type' => 'static',", $commandTester->getDisplay());
+        $this->assertStringContainsString("Mage::getModel('eav/entity_attribute')->loadByCode('catalog_product', 'sku');", $commandTester->getDisplay());
     }
 }
diff --git a/tests/N98/Magento/Command/Developer/SymlinksCommandTest.php b/tests/N98/Magento/Command/Developer/SymlinksCommandTest.php
index 508320115..30e5b94a8 100644
--- a/tests/N98/Magento/Command/Developer/SymlinksCommandTest.php
+++ b/tests/N98/Magento/Command/Developer/SymlinksCommandTest.php
@@ -1,30 +1,33 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\Developer;
 
 use N98\Magento\Command\TestCase;
 use Symfony\Component\Console\Tester\CommandTester;
 
-class SymlinksCommandTest extends TestCase
+final class SymlinksCommandTest extends TestCase
 {
     public function testExecute()
     {
         $application = $this->getApplication();
         $application->add(new SymlinksCommand());
         $application->setAutoExit(false);
+
         $command = $this->getApplication()->find('dev:symlinks');
 
         $commandTester = new CommandTester($command);
         $commandTester->execute(
             ['command'  => $command->getName(), '--global' => true, '--on'     => true],
         );
-        self::assertMatchesRegularExpression('/Symlinks allowed/', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression('/Symlinks allowed/', $commandTester->getDisplay());
 
         $commandTester = new CommandTester($command);
         $commandTester->execute(
             ['command'  => $command->getName(), '--global' => true, '--off'    => true],
         );
 
-        self::assertMatchesRegularExpression('/Symlinks denied/', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression('/Symlinks denied/', $commandTester->getDisplay());
     }
 }
diff --git a/tests/N98/Magento/Command/Developer/TemplateHintsBlocksCommandTest.php b/tests/N98/Magento/Command/Developer/TemplateHintsBlocksCommandTest.php
index 19fe682ba..8748fbdd6 100644
--- a/tests/N98/Magento/Command/Developer/TemplateHintsBlocksCommandTest.php
+++ b/tests/N98/Magento/Command/Developer/TemplateHintsBlocksCommandTest.php
@@ -1,30 +1,33 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\Developer;
 
 use N98\Magento\Command\TestCase;
 use Symfony\Component\Console\Tester\CommandTester;
 
-class TemplateHintsBlocksCommandTest extends TestCase
+final class TemplateHintsBlocksCommandTest extends TestCase
 {
     public function testExecute()
     {
         $application = $this->getApplication();
         $application->add(new TemplateHintsBlocksCommand());
         $application->setAutoExit(false);
+
         $command = $this->getApplication()->find('dev:template-hints-blocks');
 
         $commandTester = new CommandTester($command);
         $commandTester->execute(
             ['command'  => $command->getName(), '--on'     => true, 'store'    => 'admin'],
         );
-        self::assertMatchesRegularExpression('/Template Hints Blocks enabled/', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression('/Template Hints Blocks enabled/', $commandTester->getDisplay());
 
         $commandTester = new CommandTester($command);
         $commandTester->execute(
             ['command'  => $command->getName(), '--off'    => true, 'store'    => 'admin'],
         );
 
-        self::assertMatchesRegularExpression('/Template Hints Blocks disabled/', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression('/Template Hints Blocks disabled/', $commandTester->getDisplay());
     }
 }
diff --git a/tests/N98/Magento/Command/Developer/TemplateHintsCommandTest.php b/tests/N98/Magento/Command/Developer/TemplateHintsCommandTest.php
index b259dcec7..666e9e69e 100644
--- a/tests/N98/Magento/Command/Developer/TemplateHintsCommandTest.php
+++ b/tests/N98/Magento/Command/Developer/TemplateHintsCommandTest.php
@@ -1,30 +1,33 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\Developer;
 
 use N98\Magento\Command\TestCase;
 use Symfony\Component\Console\Tester\CommandTester;
 
-class TemplateHintsCommandTest extends TestCase
+final class TemplateHintsCommandTest extends TestCase
 {
     public function testExecute()
     {
         $application = $this->getApplication();
         $application->add(new TemplateHintsCommand());
         $application->setAutoExit(false);
+
         $command = $this->getApplication()->find('dev:template-hints');
 
         $commandTester = new CommandTester($command);
         $commandTester->execute(
             ['command'  => $command->getName(), '--on'     => true, 'store'    => 'admin'],
         );
-        self::assertMatchesRegularExpression('/Template Hints enabled/', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression('/Template Hints enabled/', $commandTester->getDisplay());
 
         $commandTester = new CommandTester($command);
         $commandTester->execute(
             ['command'  => $command->getName(), '--off'    => true, 'store'    => 'admin'],
         );
 
-        self::assertMatchesRegularExpression('/Template Hints disabled/', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression('/Template Hints disabled/', $commandTester->getDisplay());
     }
 }
diff --git a/tests/N98/Magento/Command/Developer/Theme/DuplicatesCommandTest.php b/tests/N98/Magento/Command/Developer/Theme/DuplicatesCommandTest.php
index 91c61a015..6932f5a38 100644
--- a/tests/N98/Magento/Command/Developer/Theme/DuplicatesCommandTest.php
+++ b/tests/N98/Magento/Command/Developer/Theme/DuplicatesCommandTest.php
@@ -1,16 +1,19 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\Developer\Theme;
 
 use N98\Magento\Command\TestCase;
 use Symfony\Component\Console\Tester\CommandTester;
 
-class DuplicatesCommandTest extends TestCase
+final class DuplicatesCommandTest extends TestCase
 {
     public function testExecute()
     {
         $application = $this->getApplication();
         $application->add(new DuplicatesCommand());
+
         $command = $this->getApplication()->find('dev:theme:duplicates');
 
         $commandTester = new CommandTester($command);
@@ -22,7 +25,7 @@ public function testExecute()
 
         $this->assertContainsPath('template/catalog/product/price.phtml', $display);
         $this->assertContainsPath('layout/catalog.xml', $display);
-        self::assertStringNotContainsString('No duplicates was found', $display);
+        $this->assertStringNotContainsString('No duplicates was found', $display);
     }
 
     /**
@@ -40,12 +43,13 @@ private function assertContainsPath($path, $haystack)
         $pattern = '~';
         while ($segment = array_shift($segments)) {
             $pattern .= preg_quote($segment, '~');
-            if ($segments) {
-                $pattern .= $segmentCount++ ? '\\1' : $separator;
+            if ($segments !== []) {
+                $pattern .= $segmentCount++ !== 0 ? '\\1' : $separator;
             }
         }
+
         $pattern .= '~';
 
-        self::assertMatchesRegularExpression($pattern, $haystack);
+        $this->assertMatchesRegularExpression($pattern, $haystack);
     }
 }
diff --git a/tests/N98/Magento/Command/Developer/Theme/InfoCommandTest.php b/tests/N98/Magento/Command/Developer/Theme/InfoCommandTest.php
index 70fe8fea1..a44a8ec5a 100644
--- a/tests/N98/Magento/Command/Developer/Theme/InfoCommandTest.php
+++ b/tests/N98/Magento/Command/Developer/Theme/InfoCommandTest.php
@@ -1,16 +1,19 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\Developer\Theme;
 
 use N98\Magento\Command\TestCase;
 use Symfony\Component\Console\Tester\CommandTester;
 
-class InfoCommandTest extends TestCase
+final class InfoCommandTest extends TestCase
 {
     public function testExecute()
     {
         $application = $this->getApplication();
         $application->add(new ListCommand());
+
         $command = $this->getApplication()->find('dev:theme:info');
 
         $commandTester = new CommandTester($command);
@@ -18,7 +21,7 @@ public function testExecute()
             ['command' => $command->getName()],
         );
 
-        self::assertStringContainsString('base/default', $commandTester->getDisplay());
-        self::assertStringContainsString('Design Package Name', $commandTester->getDisplay());
+        $this->assertStringContainsString('base/default', $commandTester->getDisplay());
+        $this->assertStringContainsString('Design Package Name', $commandTester->getDisplay());
     }
 }
diff --git a/tests/N98/Magento/Command/Developer/Theme/ListCommandTest.php b/tests/N98/Magento/Command/Developer/Theme/ListCommandTest.php
index 15f429276..dc08839b9 100644
--- a/tests/N98/Magento/Command/Developer/Theme/ListCommandTest.php
+++ b/tests/N98/Magento/Command/Developer/Theme/ListCommandTest.php
@@ -1,16 +1,19 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\Developer\Theme;
 
 use N98\Magento\Command\TestCase;
 use Symfony\Component\Console\Tester\CommandTester;
 
-class ListCommandTest extends TestCase
+final class ListCommandTest extends TestCase
 {
     public function testExecute()
     {
         $application = $this->getApplication();
         $application->add(new ListCommand());
+
         $command = $this->getApplication()->find('dev:theme:list');
 
         $commandTester = new CommandTester($command);
@@ -18,6 +21,6 @@ public function testExecute()
             ['command' => $command->getName()],
         );
 
-        self::assertStringContainsString('base/default', $commandTester->getDisplay());
+        $this->assertStringContainsString('base/default', $commandTester->getDisplay());
     }
 }
diff --git a/tests/N98/Magento/Command/Developer/Translate/InlineAdminCommandTest.php b/tests/N98/Magento/Command/Developer/Translate/InlineAdminCommandTest.php
index f223e40e2..edfeedf7e 100644
--- a/tests/N98/Magento/Command/Developer/Translate/InlineAdminCommandTest.php
+++ b/tests/N98/Magento/Command/Developer/Translate/InlineAdminCommandTest.php
@@ -1,30 +1,33 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\Developer\Translate;
 
 use N98\Magento\Command\TestCase;
 use Symfony\Component\Console\Tester\CommandTester;
 
-class InlineAdminCommandTest extends TestCase
+final class InlineAdminCommandTest extends TestCase
 {
     public function testExecute()
     {
         $application = $this->getApplication();
         $application->add(new InlineAdminCommand());
         $application->setAutoExit(false);
+
         $command = $this->getApplication()->find('dev:translate:admin');
 
         $commandTester = new CommandTester($command);
         $commandTester->execute(
             ['command'  => $command->getName(), '--on'     => true],
         );
-        self::assertStringContainsString('Inline Translation (Admin) enabled', $commandTester->getDisplay());
+        $this->assertStringContainsString('Inline Translation (Admin) enabled', $commandTester->getDisplay());
 
         $commandTester = new CommandTester($command);
         $commandTester->execute(
             ['command'  => $command->getName(), '--off'    => true],
         );
 
-        self::assertStringContainsString('Inline Translation (Admin) disabled', $commandTester->getDisplay());
+        $this->assertStringContainsString('Inline Translation (Admin) disabled', $commandTester->getDisplay());
     }
 }
diff --git a/tests/N98/Magento/Command/Developer/Translate/InlineShopCommandTest.php b/tests/N98/Magento/Command/Developer/Translate/InlineShopCommandTest.php
index 6fdac6857..39d6932d0 100644
--- a/tests/N98/Magento/Command/Developer/Translate/InlineShopCommandTest.php
+++ b/tests/N98/Magento/Command/Developer/Translate/InlineShopCommandTest.php
@@ -1,30 +1,33 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\Developer\Translate;
 
 use N98\Magento\Command\TestCase;
 use Symfony\Component\Console\Tester\CommandTester;
 
-class InlineShopCommandTest extends TestCase
+final class InlineShopCommandTest extends TestCase
 {
     public function testExecute()
     {
         $application = $this->getApplication();
         $application->add(new InlineAdminCommand());
         $application->setAutoExit(false);
+
         $command = $this->getApplication()->find('dev:translate:shop');
 
         $commandTester = new CommandTester($command);
         $commandTester->execute(
             ['command'  => $command->getName(), 'store'    => 'admin', '--on'     => true],
         );
-        self::assertStringContainsString('Inline Translation enabled', $commandTester->getDisplay());
+        $this->assertStringContainsString('Inline Translation enabled', $commandTester->getDisplay());
 
         $commandTester = new CommandTester($command);
         $commandTester->execute(
             ['command'  => $command->getName(), 'store'    => 'admin', '--off'    => true],
         );
 
-        self::assertStringContainsString('Inline Translation disabled', $commandTester->getDisplay());
+        $this->assertStringContainsString('Inline Translation disabled', $commandTester->getDisplay());
     }
 }
diff --git a/tests/N98/Magento/Command/Developer/Translate/SetCommandTest.php b/tests/N98/Magento/Command/Developer/Translate/SetCommandTest.php
index 655a21c67..63de0940a 100644
--- a/tests/N98/Magento/Command/Developer/Translate/SetCommandTest.php
+++ b/tests/N98/Magento/Command/Developer/Translate/SetCommandTest.php
@@ -1,23 +1,26 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\Developer\Translate;
 
 use N98\Magento\Command\TestCase;
 use Symfony\Component\Console\Tester\CommandTester;
 
-class SetCommandTest extends TestCase
+final class SetCommandTest extends TestCase
 {
     public function testExecute()
     {
         $application = $this->getApplication();
         $application->add(new InlineAdminCommand());
         $application->setAutoExit(false);
+
         $command = $this->getApplication()->find('dev:translate:set');
 
         $commandTester = new CommandTester($command);
         $commandTester->execute(
             ['command'   => $command->getName(), 'string'    => 'foo', 'translate' => 'bar', 'store'     => 'admin'],
         );
-        self::assertStringContainsString('foo => bar', $commandTester->getDisplay());
+        $this->assertStringContainsString('foo => bar', $commandTester->getDisplay());
     }
 }
diff --git a/tests/N98/Magento/Command/Eav/Attribute/Create/DummyCommandTest.php b/tests/N98/Magento/Command/Eav/Attribute/Create/DummyCommandTest.php
index 38c602c93..5995002e1 100644
--- a/tests/N98/Magento/Command/Eav/Attribute/Create/DummyCommandTest.php
+++ b/tests/N98/Magento/Command/Eav/Attribute/Create/DummyCommandTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\Eav\Attribute\Create;
 
 use Symfony\Component\Console\Helper\QuestionHelper;
@@ -9,12 +11,13 @@
 use N98\Magento\Command\TestCase;
 use Symfony\Component\Console\Tester\CommandTester;
 
-class DummyCommandTest extends TestCase
+final class DummyCommandTest extends TestCase
 {
     public function testExecute()
     {
         $application = $this->getApplication();
         $application->add(new DummyCommand());
+
         $command = $application->find('eav:attribute:create-dummy-values');
         $commandTester = new CommandTester($command);
 
@@ -22,13 +25,14 @@ public function testExecute()
             ['command'       => $command->getName(), 'locale'        => 'en_US', 'attribute-id'  => 92, 'values-type'   => 'int', 'values-number' => 1],
         );
 
-        self::assertMatchesRegularExpression('/ATTRIBUTE VALUE: \'(.+)\' ADDED!/', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression("/ATTRIBUTE VALUE: '(.+)' ADDED!/", $commandTester->getDisplay());
     }
 
     public function testmanageArguments()
     {
         $application = $this->getApplication();
         $application->add(new DummyCommand());
+
         $command = $application->find('eav:attribute:create-dummy-values');
 
         $dialog = $this->getMockBuilder(QuestionHelper::class)
@@ -76,8 +80,8 @@ public function testmanageArguments()
         );
 
         $arguments = $commandTester->getInput()->getArguments();
-        self::assertArrayHasKey('attribute-id', $arguments);
-        self::assertArrayHasKey('values-type', $arguments);
-        self::assertArrayHasKey('values-number', $arguments);
+        $this->assertArrayHasKey('attribute-id', $arguments);
+        $this->assertArrayHasKey('values-type', $arguments);
+        $this->assertArrayHasKey('values-number', $arguments);
     }
 }
diff --git a/tests/N98/Magento/Command/Eav/Attribute/ListCommandTest.php b/tests/N98/Magento/Command/Eav/Attribute/ListCommandTest.php
index 9d8da2482..966228d4a 100644
--- a/tests/N98/Magento/Command/Eav/Attribute/ListCommandTest.php
+++ b/tests/N98/Magento/Command/Eav/Attribute/ListCommandTest.php
@@ -1,16 +1,19 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\Eav\Attribute;
 
 use N98\Magento\Command\TestCase;
 use Symfony\Component\Console\Tester\CommandTester;
 
-class ListCommandTest extends TestCase
+final class ListCommandTest extends TestCase
 {
     public function testExecute()
     {
         $application = $this->getApplication();
         $application->add(new ListCommand());
+
         $command = $this->getApplication()->find('eav:attribute:list');
 
         $commandTester = new CommandTester($command);
@@ -18,8 +21,8 @@ public function testExecute()
             ['command'       => $command->getName(), '--filter-type' => 'catalog_product', '--add-source'  => true],
         );
 
-        self::assertStringContainsString('eav/entity_attribute_source_boolean', $commandTester->getDisplay());
-        self::assertStringContainsString('sku', $commandTester->getDisplay());
-        self::assertStringContainsString('catalog_product', $commandTester->getDisplay());
+        $this->assertStringContainsString('eav/entity_attribute_source_boolean', $commandTester->getDisplay());
+        $this->assertStringContainsString('sku', $commandTester->getDisplay());
+        $this->assertStringContainsString('catalog_product', $commandTester->getDisplay());
     }
 }
diff --git a/tests/N98/Magento/Command/Eav/Attribute/RemoveCommandTest.php b/tests/N98/Magento/Command/Eav/Attribute/RemoveCommandTest.php
index b058bf1c6..ffbc549db 100644
--- a/tests/N98/Magento/Command/Eav/Attribute/RemoveCommandTest.php
+++ b/tests/N98/Magento/Command/Eav/Attribute/RemoveCommandTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\Eav\Attribute;
 
 use InvalidArgumentException;
@@ -12,13 +14,14 @@
  * @package N98\Magento\Command\Eav\Attribute
  * @author Aydin Hassan <aydin@hotmail.co.uk>
  */
-class RemoveCommandTest extends TestCase
+final class RemoveCommandTest extends TestCase
 {
     public function testCommandThrowsExceptionIfInvalidEntityType()
     {
         $application = $this->getApplication();
         $application->add(new RemoveCommand());
         $application->setAutoExit(false);
+
         $command = $this->getApplication()->find('eav:attribute:remove');
 
         $this->expectException(InvalidArgumentException::class);
@@ -34,6 +37,7 @@ public function testCommandPrintsErrorIfAttributeNotExists()
         $application = $this->getApplication();
         $application->add(new RemoveCommand());
         $application->setAutoExit(false);
+
         $command = $this->getApplication()->find('eav:attribute:remove');
 
         $commandTester = new CommandTester($command);
@@ -41,10 +45,7 @@ public function testCommandPrintsErrorIfAttributeNotExists()
             ['command'       => $command->getName(), 'entityType'    => 'catalog_product', 'attributeCode' => ['not_an_attribute']],
         );
 
-        self::assertStringContainsString(
-            'Attribute: "not_an_attribute" does not exist for entity type: "catalog_product"',
-            $commandTester->getDisplay(),
-        );
+        $this->assertStringContainsString('Attribute: "not_an_attribute" does not exist for entity type: "catalog_product"', $commandTester->getDisplay());
     }
 
     public function testAttributeIsSuccessfullyRemoved()
@@ -52,19 +53,20 @@ public function testAttributeIsSuccessfullyRemoved()
         $application = $this->getApplication();
         $application->add(new RemoveCommand());
         $application->setAutoExit(false);
+
         $command = $this->getApplication()->find('eav:attribute:remove');
 
         $entityType = 'catalog_product';
         $attributeCode = 'crazyCoolAttribute';
         $this->createAttribute($entityType, $attributeCode, ['type'  => 'text', 'input' => 'text', 'label' => 'Test Attribute']);
 
-        self::assertTrue($this->attributeExists($entityType, $attributeCode));
+        $this->assertTrue($this->attributeExists($entityType, $attributeCode));
         $commandTester = new CommandTester($command);
         $commandTester->execute(
             ['command'       => $command->getName(), 'entityType'    => $entityType, 'attributeCode' => [$attributeCode]],
         );
 
-        self::assertFalse($this->attributeExists($entityType, $attributeCode));
+        $this->assertFalse($this->attributeExists($entityType, $attributeCode));
     }
 
     /**
@@ -76,18 +78,19 @@ public function testOrderAttributeIsSuccessfullyRemoved($entityTypeCode)
         $application = $this->getApplication();
         $application->add(new RemoveCommand());
         $application->setAutoExit(false);
+
         $command = $this->getApplication()->find('eav:attribute:remove');
 
         $attributeCode = 'crazyCoolAttribute';
         $this->createAttribute($entityTypeCode, $attributeCode, ['type'  => 'text', 'input' => 'text', 'label' => 'Test Attribute']);
 
-        self::assertTrue($this->attributeExists($entityTypeCode, $attributeCode));
+        $this->assertTrue($this->attributeExists($entityTypeCode, $attributeCode));
         $commandTester = new CommandTester($command);
         $commandTester->execute(
             ['command'       => $command->getName(), 'entityType'    => $entityTypeCode, 'attributeCode' => [$attributeCode]],
         );
 
-        self::assertFalse($this->attributeExists($entityTypeCode, $attributeCode));
+        $this->assertFalse($this->attributeExists($entityTypeCode, $attributeCode));
     }
 
     public function testCanRemoveMultipleAttributes()
@@ -95,6 +98,7 @@ public function testCanRemoveMultipleAttributes()
         $application = $this->getApplication();
         $application->add(new RemoveCommand());
         $application->setAutoExit(false);
+
         $command = $this->getApplication()->find('eav:attribute:remove');
 
         $attributeCode1 = 'crazyCoolAttribute1';
@@ -103,25 +107,19 @@ public function testCanRemoveMultipleAttributes()
 
         $this->createAttribute('catalog_product', $attributeCode2, ['type'  => 'text', 'input' => 'text', 'label' => 'Test Attribute 2']);
 
-        self::assertTrue($this->attributeExists('catalog_product', $attributeCode1));
-        self::assertTrue($this->attributeExists('catalog_product', $attributeCode2));
+        $this->assertTrue($this->attributeExists('catalog_product', $attributeCode1));
+        $this->assertTrue($this->attributeExists('catalog_product', $attributeCode2));
         $commandTester = new CommandTester($command);
         $commandTester->execute(
             ['command'       => $command->getName(), 'entityType'    => 'catalog_product', 'attributeCode' => [$attributeCode1, $attributeCode2]],
         );
 
-        self::assertFalse($this->attributeExists('catalog_product', $attributeCode1));
-        self::assertFalse($this->attributeExists('catalog_product', $attributeCode2));
+        $this->assertFalse($this->attributeExists('catalog_product', $attributeCode1));
+        $this->assertFalse($this->attributeExists('catalog_product', $attributeCode2));
 
-        self::assertStringContainsString(
-            'Successfully removed attribute: "crazyCoolAttribute1" from entity type: "catalog_product"',
-            $commandTester->getDisplay(),
-        );
+        $this->assertStringContainsString('Successfully removed attribute: "crazyCoolAttribute1" from entity type: "catalog_product"', $commandTester->getDisplay());
 
-        self::assertStringContainsString(
-            'Successfully removed attribute: "crazyCoolAttribute2" from entity type: "catalog_product"',
-            $commandTester->getDisplay(),
-        );
+        $this->assertStringContainsString('Successfully removed attribute: "crazyCoolAttribute2" from entity type: "catalog_product"', $commandTester->getDisplay());
     }
 
     public function testCanRemoveMultipleAttributesIfSomeNotExist()
@@ -129,39 +127,41 @@ public function testCanRemoveMultipleAttributesIfSomeNotExist()
         $application = $this->getApplication();
         $application->add(new RemoveCommand());
         $application->setAutoExit(false);
+
         $command = $this->getApplication()->find('eav:attribute:remove');
 
         $attributeCode1 = 'crazyCoolAttribute1';
         $attributeCode2 = 'crazyCoolAttribute2';
         $this->createAttribute('catalog_product', $attributeCode1, ['type'  => 'text', 'input' => 'text', 'label' => 'Test Attribute 1']);
 
-        self::assertTrue($this->attributeExists('catalog_product', $attributeCode1));
-        self::assertFalse($this->attributeExists('catalog_product', $attributeCode2));
+        $this->assertTrue($this->attributeExists('catalog_product', $attributeCode1));
+        $this->assertFalse($this->attributeExists('catalog_product', $attributeCode2));
         $commandTester = new CommandTester($command);
         $commandTester->execute(
             ['command'       => $command->getName(), 'entityType'    => 'catalog_product', 'attributeCode' => [$attributeCode1, $attributeCode2]],
         );
 
-        self::assertFalse($this->attributeExists('catalog_product', $attributeCode1));
-        self::assertFalse($this->attributeExists('catalog_product', $attributeCode2));
+        $this->assertFalse($this->attributeExists('catalog_product', $attributeCode1));
+        $this->assertFalse($this->attributeExists('catalog_product', $attributeCode2));
 
-        self::assertStringContainsString(
-            'Attribute: "crazyCoolAttribute2" does not exist for entity type: "catalog_product"',
-            $commandTester->getDisplay(),
-        );
+        $this->assertStringContainsString('Attribute: "crazyCoolAttribute2" does not exist for entity type: "catalog_product"', $commandTester->getDisplay());
 
-        self::assertStringContainsString(
-            'Successfully removed attribute: "crazyCoolAttribute1" from entity type: "catalog_product"',
-            $commandTester->getDisplay(),
-        );
+        $this->assertStringContainsString('Successfully removed attribute: "crazyCoolAttribute1" from entity type: "catalog_product"', $commandTester->getDisplay());
     }
 
     /**
-     * @return array
+     * @return \Iterator<(int | string), mixed>
      */
-    public static function entityTypeProvider()
+    public static function entityTypeProvider(): \Iterator
     {
-        return [['catalog_category'], ['catalog_product'], ['creditmemo'], ['customer'], ['customer_address'], ['invoice'], ['order'], ['shipment']];
+        yield ['catalog_category'];
+        yield ['catalog_product'];
+        yield ['creditmemo'];
+        yield ['customer'];
+        yield ['customer_address'];
+        yield ['invoice'];
+        yield ['order'];
+        yield ['shipment'];
     }
 
     /**
@@ -169,7 +169,7 @@ public static function entityTypeProvider()
      * @param string $attributeCode
      * @param array $data
      */
-    protected function createAttribute($entityType, $attributeCode, $data)
+    private function createAttribute($entityType, $attributeCode, $data)
     {
         $setup = Mage::getModel('eav/entity_setup', 'core_setup');
         $setup->addAttribute($entityType, $attributeCode, $data);
@@ -187,7 +187,7 @@ protected function createAttribute($entityType, $attributeCode, $data)
      * @param string $attributeCode
      * @return bool
      */
-    protected function attributeExists($entityType, $attributeCode)
+    private function attributeExists($entityType, $attributeCode)
     {
         $codes = Mage::getModel('eav/config')->getEntityAttributeCodes($entityType);
         return in_array($attributeCode, $codes);
diff --git a/tests/N98/Magento/Command/Eav/Attribute/ViewCommandTest.php b/tests/N98/Magento/Command/Eav/Attribute/ViewCommandTest.php
index bccf9cd6c..c7320a339 100644
--- a/tests/N98/Magento/Command/Eav/Attribute/ViewCommandTest.php
+++ b/tests/N98/Magento/Command/Eav/Attribute/ViewCommandTest.php
@@ -1,16 +1,19 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\Eav\Attribute;
 
 use N98\Magento\Command\TestCase;
 use Symfony\Component\Console\Tester\CommandTester;
 
-class ViewCommandTest extends TestCase
+final class ViewCommandTest extends TestCase
 {
     public function testExecute()
     {
         $application = $this->getApplication();
         $application->add(new ListCommand());
+
         $command = $this->getApplication()->find('eav:attribute:view');
 
         $commandTester = new CommandTester($command);
@@ -18,9 +21,9 @@ public function testExecute()
             ['command'       => $command->getName(), 'entityType'    => 'catalog_product', 'attributeCode' => 'sku'],
         );
 
-        self::assertStringContainsString('sku', $commandTester->getDisplay());
-        self::assertStringContainsString('catalog_product_entity', $commandTester->getDisplay());
-        self::assertStringContainsString('Backend-Type', $commandTester->getDisplay());
-        self::assertStringContainsString('static', $commandTester->getDisplay());
+        $this->assertStringContainsString('sku', $commandTester->getDisplay());
+        $this->assertStringContainsString('catalog_product_entity', $commandTester->getDisplay());
+        $this->assertStringContainsString('Backend-Type', $commandTester->getDisplay());
+        $this->assertStringContainsString('static', $commandTester->getDisplay());
     }
 }
diff --git a/tests/N98/Magento/Command/HelpCommandTest.php b/tests/N98/Magento/Command/HelpCommandTest.php
index 9fe34aa77..092520151 100644
--- a/tests/N98/Magento/Command/HelpCommandTest.php
+++ b/tests/N98/Magento/Command/HelpCommandTest.php
@@ -1,10 +1,12 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command;
 
 use Symfony\Component\Console\Tester\CommandTester;
 
-class HelpCommandTest extends TestCase
+final class HelpCommandTest extends TestCase
 {
     public function testExecute()
     {
@@ -15,6 +17,6 @@ public function testExecute()
             ['command' => 'help'],
         );
 
-        self::assertStringContainsString('The help command displays help for a given command', $commandTester->getDisplay());
+        $this->assertStringContainsString('The help command displays help for a given command', $commandTester->getDisplay());
     }
 }
diff --git a/tests/N98/Magento/Command/Indexer/ListCommandTest.php b/tests/N98/Magento/Command/Indexer/ListCommandTest.php
index 65ef34076..3808cf0f0 100644
--- a/tests/N98/Magento/Command/Indexer/ListCommandTest.php
+++ b/tests/N98/Magento/Command/Indexer/ListCommandTest.php
@@ -1,22 +1,25 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\Indexer;
 
 use N98\Magento\Command\TestCase;
 use Symfony\Component\Console\Tester\CommandTester;
 
-class ListCommandTest extends TestCase
+final class ListCommandTest extends TestCase
 {
     public function testExecute()
     {
         $application = $this->getApplication();
         $application->add(new ListCommand());
+
         $command = $this->getApplication()->find('index:list');
 
         $commandTester = new CommandTester($command);
         $commandTester->execute(['command' => $command->getName()]);
 
         // check if i.e. at least one index is listed
-        self::assertMatchesRegularExpression('/catalog_product_flat/', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression('/catalog_product_flat/', $commandTester->getDisplay());
     }
 }
diff --git a/tests/N98/Magento/Command/Indexer/ReindexAllCommandTest.php b/tests/N98/Magento/Command/Indexer/ReindexAllCommandTest.php
index 51475dadd..cef9ca947 100644
--- a/tests/N98/Magento/Command/Indexer/ReindexAllCommandTest.php
+++ b/tests/N98/Magento/Command/Indexer/ReindexAllCommandTest.php
@@ -1,16 +1,19 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\Indexer;
 
 use N98\Magento\Command\TestCase;
 use Symfony\Component\Console\Tester\CommandTester;
 
-class ReindexAllCommandTest extends TestCase
+final class ReindexAllCommandTest extends TestCase
 {
     public function testExecute()
     {
         $application = $this->getApplication();
         $application->add(new ReindexAllCommand());
+
         $command = $this->getApplication()->find('index:reindex:all');
 
         $application->initMagento();
@@ -20,14 +23,14 @@ public function testExecute()
             ['command' => $command->getName()],
         );
 
-        self::assertStringContainsString('Successfully reindexed catalog_product_attribute', $commandTester->getDisplay());
-        self::assertStringContainsString('Successfully reindexed catalog_product_price', $commandTester->getDisplay());
-        self::assertStringContainsString('Successfully reindexed catalog_url', $commandTester->getDisplay());
-        self::assertStringContainsString('Successfully reindexed catalog_product_flat', $commandTester->getDisplay());
-        self::assertStringContainsString('Successfully reindexed catalog_category_flat', $commandTester->getDisplay());
-        self::assertStringContainsString('Successfully reindexed catalog_category_product', $commandTester->getDisplay());
-        self::assertStringContainsString('Successfully reindexed catalogsearch_fulltext', $commandTester->getDisplay());
-        self::assertStringContainsString('Successfully reindexed cataloginventory_stock', $commandTester->getDisplay());
-        self::assertStringContainsString('Successfully reindexed tag_summary', $commandTester->getDisplay());
+        $this->assertStringContainsString('Successfully reindexed catalog_product_attribute', $commandTester->getDisplay());
+        $this->assertStringContainsString('Successfully reindexed catalog_product_price', $commandTester->getDisplay());
+        $this->assertStringContainsString('Successfully reindexed catalog_url', $commandTester->getDisplay());
+        $this->assertStringContainsString('Successfully reindexed catalog_product_flat', $commandTester->getDisplay());
+        $this->assertStringContainsString('Successfully reindexed catalog_category_flat', $commandTester->getDisplay());
+        $this->assertStringContainsString('Successfully reindexed catalog_category_product', $commandTester->getDisplay());
+        $this->assertStringContainsString('Successfully reindexed catalogsearch_fulltext', $commandTester->getDisplay());
+        $this->assertStringContainsString('Successfully reindexed cataloginventory_stock', $commandTester->getDisplay());
+        $this->assertStringContainsString('Successfully reindexed tag_summary', $commandTester->getDisplay());
     }
 }
diff --git a/tests/N98/Magento/Command/Indexer/ReindexCommandTest.php b/tests/N98/Magento/Command/Indexer/ReindexCommandTest.php
index 3130f3aca..5d0b64b21 100644
--- a/tests/N98/Magento/Command/Indexer/ReindexCommandTest.php
+++ b/tests/N98/Magento/Command/Indexer/ReindexCommandTest.php
@@ -1,16 +1,19 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\Indexer;
 
 use N98\Magento\Command\TestCase;
 use Symfony\Component\Console\Tester\CommandTester;
 
-class ReindexCommandTest extends TestCase
+final class ReindexCommandTest extends TestCase
 {
     public function testExecute()
     {
         $application = $this->getApplication();
         $application->add(new ReindexCommand());
+
         $command = $this->getApplication()->find('index:reindex');
 
         $commandTester = new CommandTester($command);
@@ -18,6 +21,6 @@ public function testExecute()
             ['command'    => $command->getName(), 'index_code' => 'tag_summary,tag_summary'],
         );
 
-        self::assertStringContainsString('Successfully re-indexed tag_summary', $commandTester->getDisplay());
+        $this->assertStringContainsString('Successfully re-indexed tag_summary', $commandTester->getDisplay());
     }
 }
diff --git a/tests/N98/Magento/Command/Installer/InstallCommandPackageVersionTest.php b/tests/N98/Magento/Command/Installer/InstallCommandPackageVersionTest.php
index 348f1122c..07d7b184c 100644
--- a/tests/N98/Magento/Command/Installer/InstallCommandPackageVersionTest.php
+++ b/tests/N98/Magento/Command/Installer/InstallCommandPackageVersionTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 /**
  * this file is part of magerun
  *
@@ -15,20 +17,17 @@
  *
  * @package N98\Magento\Command\Installer
  */
-class InstallCommandPackageVersionTest extends TestCase
+final class InstallCommandPackageVersionTest extends TestCase
 {
-    /**
-     * @test that versions given are in order (latest up) across the package definitions in config.yml
-     */
-    public function versionListing()
+    public function testVersionListing()
     {
         $application = $this->getApplication();
         $application->add(new InstallCommand());
         /** @var InstallCommand $command */
         $command = $this->getApplication()->find('install');
 
-        $tester = new InstallCommandTester();
-        $packages = $tester->getMagentoPackages($command);
+        $installCommandTester = new InstallCommandTester();
+        $packages = $installCommandTester->getMagentoPackages($command);
 
         $this->assertOngoingPackageVersions($packages, 2, 5);
     }
@@ -37,7 +36,6 @@ public function versionListing()
      * helper assertion to verify that all packages with multiple versions are listet with the latest and greatest
      * version first.
      *
-     * @param array $packages
      * @param int $namespacesMinimum minimum number of package namespace (e.g. CE and mirror), normally 2
      * @param int $nonVersionsMaximum maximum number of packages that will trigger an assertion
      */
@@ -49,63 +47,58 @@ private function assertOngoingPackageVersions(array $packages, $namespacesMinimu
         $nameConstraint = [];
 
         foreach ($packages as $package) {
-            self::assertArrayHasKey('name', $package);
-            self::assertArrayHasKey('version', $package);
+            $this->assertArrayHasKey('name', $package);
+            $this->assertArrayHasKey('version', $package);
             $name = $package['name'];
             $version = $package['version'];
-            $nameAndVersion = "$name $version";
+            $nameAndVersion = sprintf('%s %s', $name, $version);
 
-            self::assertArrayNotHasKey(
-                $name,
-                $nameConstraint,
-                sprintf('duplicate package "%s"', $name),
-            );
+            $this->assertArrayNotHasKey($name, $nameConstraint, sprintf('duplicate package "%s"', $name));
             $nameConstraint[$name] = 1;
 
             if (!$this->isVersionNumber($version)) {
                 $nonVersionsList[] = $nameAndVersion;
-                $nonVersions++;
+                ++$nonVersions;
                 continue;
             }
 
             [$namespace, $nameVersion] = $this->splitName($name);
             if ($nameVersion === null || $nameVersion !== $version) {
                 $nonVersionsList[] = $name;
-                $nonVersions++;
+                ++$nonVersions;
                 continue;
             }
-            self::assertSame($version, $nameVersion);
+
+            $this->assertSame($version, $nameVersion);
 
             if (isset($nameStack[$namespace])) {
                 $comparison = version_compare($nameStack[$namespace], $version);
                 $message = sprintf(
-                    "Check order of versions for package \"$namespace\", higher comes first, but got %s before %s",
+                    sprintf('Check order of versions for package "%s", higher comes first, but got %%s before %%s', $namespace),
                     $nameStack[$namespace],
                     $version,
                 );
-                self::assertGreaterThan(0, $comparison, $message);
+                $this->assertGreaterThan(0, $comparison, $message);
             }
+
             $nameStack[$namespace] = $nameVersion;
         }
 
-        self::assertGreaterThanOrEqual($namespacesMinimum, count($nameStack));
+        $this->assertGreaterThanOrEqual($namespacesMinimum, count($nameStack));
         $message = sprintf('Too many non-versions (%s)', implode(', ', $nonVersionsList));
-        self::assertLessThan($nonVersionsMaximum, $nonVersions, $message);
+        $this->assertLessThan($nonVersionsMaximum, $nonVersions, $message);
     }
 
-    /**
-     * @test that demo-data-packages actually exist
-     */
-    public function demoDataPackages()
+    public function testDemoDataPackages()
     {
         $application = $this->getApplication();
         $application->add(new InstallCommand());
         /** @var InstallCommand $command */
         $command = $this->getApplication()->find('install');
 
-        $tester = new InstallCommandTester();
-        $packages = $tester->getMagentoPackages($command);
-        $demoDataPackages = $tester->getSampleDataPackages($command);
+        $installCommandTester = new InstallCommandTester();
+        $packages = $installCommandTester->getMagentoPackages($command);
+        $demoDataPackages = $installCommandTester->getSampleDataPackages($command);
 
         $this->assertSampleDataPackagesExist($packages, $demoDataPackages);
     }
@@ -117,13 +110,14 @@ private function assertSampleDataPackagesExist(array $packages, array $demoDataP
             $map[$package['name']] = $index;
         }
 
-        foreach ($packages as $index => $package) {
+        foreach ($packages as $package) {
             if (!isset($package['extra']['sample-data'])) {
                 continue;
             }
+
             $name = $package['extra']['sample-data'];
             $message = sprintf('Invalid sample-data "%s" (undefined) in package "%s"', $name, $package['name']);
-            self::assertArrayHasKey($name, $map, $message);
+            $this->assertArrayHasKey($name, $map, $message);
         }
     }
 
@@ -144,8 +138,11 @@ private function splitName($name)
      */
     private function isVersionNumber($buffer)
     {
-        return $this->isQuadripartiteVersionNumber($buffer)
-            || $this->isTripartiteOpenMageVersionNumber($buffer);
+        if ($this->isQuadripartiteVersionNumber($buffer)) {
+            return true;
+        }
+
+        return $this->isTripartiteOpenMageVersionNumber($buffer);
     }
 
     /**
@@ -157,7 +154,7 @@ private function isVersionNumber($buffer)
      */
     private function isTripartiteOpenMageVersionNumber($buffer)
     {
-        if (!preg_match('~^(?:19|2\d)\.\d+\.\d+$~', $buffer)) {
+        if (in_array(preg_match('~^(?:19|2\d)\.\d+\.\d+$~', $buffer), [0, false], true)) {
             return false;
         }
 
@@ -176,7 +173,7 @@ private function isTripartiteOpenMageVersionNumber($buffer)
      */
     private function isQuadripartiteVersionNumber($buffer)
     {
-        if (!preg_match('~^\d+\.\d+\.\d+\.\d+$~', $buffer)) {
+        if (in_array(preg_match('~^\d+\.\d+\.\d+\.\d+$~', $buffer), [0, false], true)) {
             return false;
         }
 
diff --git a/tests/N98/Magento/Command/Installer/InstallCommandTest.php b/tests/N98/Magento/Command/Installer/InstallCommandTest.php
index 8fb1de652..ecdc6fe8a 100644
--- a/tests/N98/Magento/Command/Installer/InstallCommandTest.php
+++ b/tests/N98/Magento/Command/Installer/InstallCommandTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\Installer;
 
 use InvalidArgumentException;
@@ -7,17 +9,17 @@
 use RuntimeException;
 use Symfony\Component\Console\Tester\CommandTester;
 
-class InstallCommandTest extends TestCase
+final class InstallCommandTest extends TestCase
 {
     /**
      * @var string Installation Directory
      */
-    protected $installDir;
+    private $installDir;
 
     /**
      * Create temp dir for install
      */
-    public function setup(): void
+    protected function setup(): void
     {
         $installDir = sys_get_temp_dir() . '/mageinstall';
         if (is_readable($installDir)) {
@@ -41,6 +43,7 @@ public function testInstallFailsWithInvalidDbConfigWhenAllOptionsArePassedIn()
         $this->markTestIncomplete('With PHPUnit 10 the test is waiting forever. This has to be fixed.');
         $application = $this->getApplication();
         $application->add(new InstallCommand());
+
         $command = $this->getApplication()->find('install');
         $commandTester = new CommandTester($command);
 
@@ -58,10 +61,10 @@ public function testInstallFailsWithInvalidDbConfigWhenAllOptionsArePassedIn()
                     '--dbName' => 'magento',
                 ],
             );
-        } catch (InvalidArgumentException $e) {
-            self::assertEquals('Database configuration is invalid', $e->getMessage());
+        } catch (InvalidArgumentException $invalidArgumentException) {
+            $this->assertSame('Database configuration is invalid', $invalidArgumentException->getMessage());
             $display = $commandTester->getDisplay(true);
-            self::assertStringContainsString('SQLSTATE', $display);
+            $this->assertStringContainsString('SQLSTATE', $display);
 
             return;
         }
@@ -72,7 +75,7 @@ public function testInstallFailsWithInvalidDbConfigWhenAllOptionsArePassedIn()
     /**
      * Remove directory made by installer
      */
-    public function tearDown(): void
+    protected function tearDown(): void
     {
         if (is_readable($this->installDir)) {
             @rmdir($this->installDir);
diff --git a/tests/N98/Magento/Command/Installer/InstallCommandTester.php b/tests/N98/Magento/Command/Installer/InstallCommandTester.php
index 93299f1d6..c0154fd80 100644
--- a/tests/N98/Magento/Command/Installer/InstallCommandTester.php
+++ b/tests/N98/Magento/Command/Installer/InstallCommandTester.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 /**
  * this file is part of magerun
  *
@@ -18,24 +20,22 @@ class InstallCommandTester extends InstallCommand
     public const COMMAND_CLASS = 'N98\Magento\Command\Installer\InstallCommand';
 
     /**
-     * @param InstallCommand $command
      * @return array
      */
-    public function getMagentoPackages(InstallCommand $command)
+    public function getMagentoPackages(InstallCommand $installCommand)
     {
         $commandClass = self::COMMAND_CLASS;
-        $commandConfig = $command->getCommandConfig($commandClass);
+        $commandConfig = $installCommand->getCommandConfig($commandClass);
         return $commandConfig['magento-packages'];
     }
 
     /**
-     * @param InstallCommand $command
      * @return array
      */
-    public function getSampleDataPackages(InstallCommand $command)
+    public function getSampleDataPackages(InstallCommand $installCommand)
     {
         $commandClass = self::COMMAND_CLASS;
-        $commandConfig = $command->getCommandConfig($commandClass);
+        $commandConfig = $installCommand->getCommandConfig($commandClass);
         return $commandConfig['demo-data-packages'];
     }
 }
diff --git a/tests/N98/Magento/Command/Installer/UninstallCommandTest.php b/tests/N98/Magento/Command/Installer/UninstallCommandTest.php
index 9939c90b6..53d63176e 100644
--- a/tests/N98/Magento/Command/Installer/UninstallCommandTest.php
+++ b/tests/N98/Magento/Command/Installer/UninstallCommandTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\Installer;
 
 use N98\Magento\Command\TestCase;
@@ -12,7 +14,7 @@
  * @package N98\Magento\Command\Installer
  * @author  Aydin Hassan <aydin@hotmail.co.uk>
  */
-class UninstallCommandTest extends TestCase
+final class UninstallCommandTest extends TestCase
 {
     /**
      * Check that Magento is not removed if confirmation is denied
@@ -22,19 +24,21 @@ public function testUninstallDoesNotUninstallIfConfirmationDenied()
         $this->markTestIncomplete('Find a replacement for setInputStream() of old DialogHelper');
         $application = $this->getApplication();
         $application->add(new UninstallCommand());
+
         $command = $this->getApplication()->find('uninstall');
 
         $commandTester = new CommandTester($command);
 
         $dialog = new QuestionHelper();
         $dialog->setInputStream($this->getInputStream('no\n'));
+
         $command->setHelperSet(new HelperSet([$dialog]));
 
         $commandTester->execute(['command'               => $command->getName(), '--installationFolder'  => $this->getTestMagentoRoot()]);
-        self::assertEquals('Really uninstall ? [n]: ', $commandTester->getDisplay());
+        $this->assertSame('Really uninstall ? [n]: ', $commandTester->getDisplay());
 
         //check magento still installed
-        self::assertFileExists($this->getTestMagentoRoot() . '/app/etc/local.xml');
+        $this->assertFileExists($this->getTestMagentoRoot() . '/app/etc/local.xml');
     }
 
     /**
@@ -45,6 +49,7 @@ public function testUninstallForceActuallyRemoves()
         $this->markTestIncomplete('Find a replacement for setInputStream() of old DialogHelper');
         $application = $this->getApplication();
         $application->add(new UninstallCommand());
+
         $command = $this->getApplication()->find('uninstall');
 
         $commandTester = new CommandTester($command);
@@ -53,20 +58,20 @@ public function testUninstallForceActuallyRemoves()
             ['command'               => $command->getName(), '--force'               => true, '--installationFolder'  => $this->getTestMagentoRoot()],
         );
 
-        self::assertStringContainsString('Dropped database', $commandTester->getDisplay());
-        self::assertStringContainsString('Remove directory ' . $this->getTestMagentoRoot(), $commandTester->getDisplay());
-        self::assertStringContainsString('Done', $commandTester->getDisplay());
-        self::assertFileDoesNotExist($this->getTestMagentoRoot() . '/app/etc/local.xml');
+        $this->assertStringContainsString('Dropped database', $commandTester->getDisplay());
+        $this->assertStringContainsString('Remove directory ' . $this->getTestMagentoRoot(), $commandTester->getDisplay());
+        $this->assertStringContainsString('Done', $commandTester->getDisplay());
+        $this->assertFileDoesNotExist($this->getTestMagentoRoot() . '/app/etc/local.xml');
     }
 
     /**
      * @param $input
      * @return resource
      */
-    protected function getInputStream($input)
+    private function getInputStream($input)
     {
         $stream = fopen('php://memory', 'rb+', false);
-        fputs($stream, $input);
+        fwrite($stream, $input);
         rewind($stream);
         return $stream;
     }
diff --git a/tests/N98/Magento/Command/ListCommandTest.php b/tests/N98/Magento/Command/ListCommandTest.php
index 55d2f73d6..d32e7b6fa 100644
--- a/tests/N98/Magento/Command/ListCommandTest.php
+++ b/tests/N98/Magento/Command/ListCommandTest.php
@@ -1,10 +1,12 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command;
 
 use Symfony\Component\Console\Tester\CommandTester;
 
-class ListCommandTest extends TestCase
+final class ListCommandTest extends TestCase
 {
     public function testExecute()
     {
@@ -15,9 +17,6 @@ public function testExecute()
             ['command' => 'list'],
         );
 
-        self::assertStringContainsString(
-            sprintf('n98-magerun %s by valantic CEC', $this->getApplication()->getVersion()),
-            $commandTester->getDisplay(),
-        );
+        $this->assertStringContainsString(sprintf('n98-magerun %s by valantic CEC', $this->getApplication()->getVersion()), $commandTester->getDisplay());
     }
 }
diff --git a/tests/N98/Magento/Command/LocalConfig/GenerateCommandTest.php b/tests/N98/Magento/Command/LocalConfig/GenerateCommandTest.php
index 71c677170..64299dc47 100644
--- a/tests/N98/Magento/Command/LocalConfig/GenerateCommandTest.php
+++ b/tests/N98/Magento/Command/LocalConfig/GenerateCommandTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 /** @noinspection SimpleXmlLoadFileUsageInspection */
 
 namespace N98\Magento\Command\LocalConfig;
@@ -13,14 +15,14 @@
 use Symfony\Component\Console\Question\Question;
 use Symfony\Component\Console\Tester\CommandTester;
 
-class GenerateCommandTest extends TestCase
+final class GenerateCommandTest extends TestCase
 {
     /**
      * @var string
      */
     private $configFile;
 
-    public function setUp(): void
+    protected function setUp(): void
     {
         $this->configFile = sprintf('%s/%s/local.xml', sys_get_temp_dir(), $this->getName());
         mkdir(dirname($this->configFile), 0777, true);
@@ -61,11 +63,8 @@ public function testErrorIsPrintedIfConfigFileExists()
             ],
         );
 
-        self::assertFileExists($this->configFile);
-        self::assertStringContainsString(
-            sprintf('local.xml file already exists in folder "%s/app/etc"', dirname($this->configFile)),
-            $commandTester->getDisplay(),
-        );
+        $this->assertFileExists($this->configFile);
+        $this->assertStringContainsString(sprintf('local.xml file already exists in folder "%s/app/etc"', dirname($this->configFile)), $commandTester->getDisplay());
     }
 
     public function testErrorIsPrintedIfConfigTemplateNotExists()
@@ -86,10 +85,7 @@ public function testErrorIsPrintedIfConfigTemplateNotExists()
             ],
         );
 
-        self::assertStringContainsString(
-            sprintf('File %s/local.xml.template does not exist', dirname($this->configFile)),
-            $commandTester->getDisplay(),
-        );
+        $this->assertStringContainsString(sprintf('File %s/local.xml.template does not exist', dirname($this->configFile)), $commandTester->getDisplay());
     }
 
     public function testErrorIsPrintedIfAppEtcDirNotWriteable()
@@ -113,10 +109,7 @@ public function testErrorIsPrintedIfAppEtcDirNotWriteable()
             ],
         );
 
-        self::assertStringContainsString(
-            sprintf('Folder %s is not writeable', dirname($this->configFile)),
-            $commandTester->getDisplay(),
-        );
+        $this->assertStringContainsString(sprintf('Folder %s is not writeable', dirname($this->configFile)), $commandTester->getDisplay());
 
         chmod(dirname($this->configFile), $originalMode);
     }
@@ -138,18 +131,18 @@ public function testRandomMd5IsUsedIfNoEncryptionKeyParamPassed()
             ],
         );
 
-        self::assertFileExists($this->configFile);
+        $this->assertFileExists($this->configFile);
         $fileContent = \file_get_contents($this->configFile);
-        self::assertStringContainsString('<host><![CDATA[my_db_host]]></host>', $fileContent);
-        self::assertStringContainsString('<username><![CDATA[my_db_user]]></username>', $fileContent);
-        self::assertStringContainsString('<password><![CDATA[my_db_pass]]></password>', $fileContent);
-        self::assertStringContainsString('<dbname><![CDATA[my_db_name]]></dbname>', $fileContent);
-        self::assertStringContainsString('<session_save><![CDATA[my_session_save]]></session_save>', $fileContent);
-        self::assertStringContainsString('<frontName><![CDATA[my_admin_frontname]]></frontName>', $fileContent);
-        self::assertMatchesRegularExpression('/<key><!\[CDATA\[[a-f0-9]{32}\]\]><\/key>/', $fileContent);
+        $this->assertStringContainsString('<host><![CDATA[my_db_host]]></host>', $fileContent);
+        $this->assertStringContainsString('<username><![CDATA[my_db_user]]></username>', $fileContent);
+        $this->assertStringContainsString('<password><![CDATA[my_db_pass]]></password>', $fileContent);
+        $this->assertStringContainsString('<dbname><![CDATA[my_db_name]]></dbname>', $fileContent);
+        $this->assertStringContainsString('<session_save><![CDATA[my_session_save]]></session_save>', $fileContent);
+        $this->assertStringContainsString('<frontName><![CDATA[my_admin_frontname]]></frontName>', $fileContent);
+        $this->assertMatchesRegularExpression('/<key><!\[CDATA\[[a-f0-9]{32}\]\]><\/key>/', $fileContent);
 
         $xml = \simplexml_load_file($this->configFile);
-        self::assertIsNotBool($xml);
+        $this->assertIsNotBool($xml);
     }
 
     public function testExecuteWithCliParameters()
@@ -170,18 +163,18 @@ public function testExecuteWithCliParameters()
             ],
         );
 
-        self::assertFileExists($this->configFile);
+        $this->assertFileExists($this->configFile);
         $fileContent = \file_get_contents($this->configFile);
-        self::assertStringContainsString('<host><![CDATA[my_db_host]]></host>', $fileContent);
-        self::assertStringContainsString('<username><![CDATA[my_db_user]]></username>', $fileContent);
-        self::assertStringContainsString('<password><![CDATA[my_db_pass]]></password>', $fileContent);
-        self::assertStringContainsString('<dbname><![CDATA[my_db_name]]></dbname>', $fileContent);
-        self::assertStringContainsString('<session_save><![CDATA[my_session_save]]></session_save>', $fileContent);
-        self::assertStringContainsString('<frontName><![CDATA[my_admin_frontname]]></frontName>', $fileContent);
-        self::assertStringContainsString('<key><![CDATA[key123456789]]></key>', $fileContent);
+        $this->assertStringContainsString('<host><![CDATA[my_db_host]]></host>', $fileContent);
+        $this->assertStringContainsString('<username><![CDATA[my_db_user]]></username>', $fileContent);
+        $this->assertStringContainsString('<password><![CDATA[my_db_pass]]></password>', $fileContent);
+        $this->assertStringContainsString('<dbname><![CDATA[my_db_name]]></dbname>', $fileContent);
+        $this->assertStringContainsString('<session_save><![CDATA[my_session_save]]></session_save>', $fileContent);
+        $this->assertStringContainsString('<frontName><![CDATA[my_admin_frontname]]></frontName>', $fileContent);
+        $this->assertStringContainsString('<key><![CDATA[key123456789]]></key>', $fileContent);
 
         $xml = \simplexml_load_file($this->configFile);
-        self::assertIsNotBool($xml);
+        $this->assertIsNotBool($xml);
     }
 
     public function testInteractiveInputUsesDefaultValuesIfNoValueEntered()
@@ -203,18 +196,18 @@ public function testInteractiveInputUsesDefaultValuesIfNoValueEntered()
             ],
         );
 
-        self::assertFileExists($this->configFile);
+        $this->assertFileExists($this->configFile);
         $fileContent = \file_get_contents($this->configFile);
-        self::assertStringContainsString('<host><![CDATA[my_db_host]]></host>', $fileContent);
-        self::assertStringContainsString('<username><![CDATA[my_db_user]]></username>', $fileContent);
-        self::assertStringContainsString('<password><![CDATA[my_db_pass]]></password>', $fileContent);
-        self::assertStringContainsString('<dbname><![CDATA[my_db_name]]></dbname>', $fileContent);
-        self::assertStringContainsString('<session_save><![CDATA[files]]></session_save>', $fileContent);
-        self::assertStringContainsString('<frontName><![CDATA[admin]]></frontName>', $fileContent);
-        self::assertStringContainsString('<key><![CDATA[key123456789]]></key>', $fileContent);
+        $this->assertStringContainsString('<host><![CDATA[my_db_host]]></host>', $fileContent);
+        $this->assertStringContainsString('<username><![CDATA[my_db_user]]></username>', $fileContent);
+        $this->assertStringContainsString('<password><![CDATA[my_db_pass]]></password>', $fileContent);
+        $this->assertStringContainsString('<dbname><![CDATA[my_db_name]]></dbname>', $fileContent);
+        $this->assertStringContainsString('<session_save><![CDATA[files]]></session_save>', $fileContent);
+        $this->assertStringContainsString('<frontName><![CDATA[admin]]></frontName>', $fileContent);
+        $this->assertStringContainsString('<key><![CDATA[key123456789]]></key>', $fileContent);
 
         $xml = \simplexml_load_file($this->configFile);
-        self::assertIsNotBool($xml);
+        $this->assertIsNotBool($xml);
     }
 
     /**
@@ -245,7 +238,7 @@ public function testRequiredOptionsThrowExceptionIfNotSet($param, $prompt, $defa
             ->onlyMethods(['ask'])
             ->getMock();
 
-        $questionHelperMock->expects(self::once())
+        $questionHelperMock->expects($this->once())
             ->method('ask')
             ->with(
                 self::isInstanceOf(InputInterface::class),
@@ -266,17 +259,15 @@ public function testRequiredOptionsThrowExceptionIfNotSet($param, $prompt, $defa
     }
 
     /**
-     * @return array
+     * @return \Iterator<(int | string), mixed>
      */
-    public function requiredFieldsProvider()
+    public function requiredFieldsProvider(): \Iterator
     {
-        return [
-            ['db-host', 'database host', ''],
-            ['db-user', 'database username', ''],
-            ['db-name', 'database name', ''],
-            ['session-save', 'session save', 'files'],
-            ['admin-frontname', 'admin frontname', 'admin'],
-        ];
+        yield ['db-host', 'database host', ''];
+        yield ['db-user', 'database username', ''];
+        yield ['db-name', 'database name', ''];
+        yield ['session-save', 'session save', 'files'];
+        yield ['admin-frontname', 'admin frontname', 'admin'];
     }
 
     public function testExecuteInteractively()
@@ -316,17 +307,17 @@ public function testExecuteInteractively()
         $commandTester = new CommandTester($command);
         $commandTester->execute(['command' => $command->getName()]);
 
-        self::assertFileExists($this->configFile);
+        $this->assertFileExists($this->configFile);
         $fileContent = \file_get_contents($this->configFile);
-        self::assertStringContainsString('<host><![CDATA[some-db-host]]></host>', $fileContent);
-        self::assertStringContainsString('<username><![CDATA[some-db-username]]></username>', $fileContent);
-        self::assertStringContainsString('<password><![CDATA[some-db-password]]></password>', $fileContent);
-        self::assertStringContainsString('<dbname><![CDATA[some-db-name]]></dbname>', $fileContent);
-        self::assertStringContainsString('<session_save><![CDATA[some-session-save]]></session_save>', $fileContent);
-        self::assertStringContainsString('<frontName><![CDATA[some-admin-front-name]]></frontName>', $fileContent);
+        $this->assertStringContainsString('<host><![CDATA[some-db-host]]></host>', $fileContent);
+        $this->assertStringContainsString('<username><![CDATA[some-db-username]]></username>', $fileContent);
+        $this->assertStringContainsString('<password><![CDATA[some-db-password]]></password>', $fileContent);
+        $this->assertStringContainsString('<dbname><![CDATA[some-db-name]]></dbname>', $fileContent);
+        $this->assertStringContainsString('<session_save><![CDATA[some-session-save]]></session_save>', $fileContent);
+        $this->assertStringContainsString('<frontName><![CDATA[some-admin-front-name]]></frontName>', $fileContent);
 
         $xml = \simplexml_load_file($this->configFile);
-        self::assertIsNotBool($xml);
+        $this->assertIsNotBool($xml);
     }
 
     public function testIfPasswordOmittedItIsWrittenBlank()
@@ -337,7 +328,7 @@ public function testIfPasswordOmittedItIsWrittenBlank()
             ->onlyMethods(['ask'])
             ->getMock();
 
-        $questionHelperMock->expects(self::once())
+        $questionHelperMock->expects($this->once())
             ->method('ask')
             ->with(
                 self::isInstanceOf(InputInterface::class),
@@ -361,18 +352,18 @@ public function testIfPasswordOmittedItIsWrittenBlank()
             ],
         );
 
-        self::assertFileExists($this->configFile);
+        $this->assertFileExists($this->configFile);
         $fileContent = \file_get_contents($this->configFile);
-        self::assertStringContainsString('<host><![CDATA[my_db_host]]></host>', $fileContent);
-        self::assertStringContainsString('<username><![CDATA[my_db_user]]></username>', $fileContent);
-        self::assertStringContainsString('<password></password>', $fileContent);
-        self::assertStringContainsString('<dbname><![CDATA[my_db_name]]></dbname>', $fileContent);
-        self::assertStringContainsString('<session_save><![CDATA[my_session_save]]></session_save>', $fileContent);
-        self::assertStringContainsString('<frontName><![CDATA[my_admin_frontname]]></frontName>', $fileContent);
-        self::assertStringContainsString('<key><![CDATA[key123456789]]></key>', $fileContent);
+        $this->assertStringContainsString('<host><![CDATA[my_db_host]]></host>', $fileContent);
+        $this->assertStringContainsString('<username><![CDATA[my_db_user]]></username>', $fileContent);
+        $this->assertStringContainsString('<password></password>', $fileContent);
+        $this->assertStringContainsString('<dbname><![CDATA[my_db_name]]></dbname>', $fileContent);
+        $this->assertStringContainsString('<session_save><![CDATA[my_session_save]]></session_save>', $fileContent);
+        $this->assertStringContainsString('<frontName><![CDATA[my_admin_frontname]]></frontName>', $fileContent);
+        $this->assertStringContainsString('<key><![CDATA[key123456789]]></key>', $fileContent);
 
         $xml = \simplexml_load_file($this->configFile);
-        self::assertIsNotBool($xml);
+        $this->assertIsNotBool($xml);
     }
 
     public function testCdataTagIsNotAddedIfPresentInInput()
@@ -383,7 +374,7 @@ public function testCdataTagIsNotAddedIfPresentInInput()
             ->onlyMethods(['ask'])
             ->getMock();
 
-        $questionHelperMock->expects(self::once())
+        $questionHelperMock->expects($this->once())
             ->method('ask')
             ->with(
                 self::isInstanceOf(InputInterface::class),
@@ -409,41 +400,39 @@ public function testCdataTagIsNotAddedIfPresentInInput()
             ],
         );
 
-        self::assertFileExists($this->configFile);
+        $this->assertFileExists($this->configFile);
         $fileContent = \file_get_contents($this->configFile);
-        self::assertStringContainsString('<host><![CDATA[CDATAdatabasehost]]></host>', $fileContent);
-        self::assertStringContainsString('<username><![CDATA[my_db_user]]></username>', $fileContent);
-        self::assertStringContainsString('<password><![CDATA[my_db_pass]]></password>', $fileContent);
-        self::assertStringContainsString('<dbname><![CDATA[my_db_name]]></dbname>', $fileContent);
-        self::assertStringContainsString('<session_save><![CDATA[my_session_save]]></session_save>', $fileContent);
-        self::assertStringContainsString('<frontName><![CDATA[my_admin_frontname]]></frontName>', $fileContent);
-        self::assertStringContainsString('<key><![CDATA[key123456789]]></key>', $fileContent);
+        $this->assertStringContainsString('<host><![CDATA[CDATAdatabasehost]]></host>', $fileContent);
+        $this->assertStringContainsString('<username><![CDATA[my_db_user]]></username>', $fileContent);
+        $this->assertStringContainsString('<password><![CDATA[my_db_pass]]></password>', $fileContent);
+        $this->assertStringContainsString('<dbname><![CDATA[my_db_name]]></dbname>', $fileContent);
+        $this->assertStringContainsString('<session_save><![CDATA[my_session_save]]></session_save>', $fileContent);
+        $this->assertStringContainsString('<frontName><![CDATA[my_admin_frontname]]></frontName>', $fileContent);
+        $this->assertStringContainsString('<key><![CDATA[key123456789]]></key>', $fileContent);
         $xml = \simplexml_load_file($this->configFile);
-        self::assertIsNotBool($xml);
+        $this->assertIsNotBool($xml);
     }
 
-    /**
-     * @test unit utility method _wrapCdata
-     */
-    public function wrapCdata()
+    public function testWrapCdata()
     {
-        $command = new GenerateCommand();
-        $refl = new ReflectionClass($command);
-        $method = $refl->getMethod('_wrapCData');
-        $method->setAccessible(true);
-        $sujet = function ($string) use ($method, $command) {
-            return $method->invoke($command, $string);
+        $generateCommand = new GenerateCommand();
+        $reflectionClass = new ReflectionClass($generateCommand);
+        $reflectionMethod = $reflectionClass->getMethod('_wrapCData');
+        $reflectionMethod->setAccessible(true);
+
+        $sujet = function ($string) use ($reflectionMethod, $generateCommand) {
+            return $reflectionMethod->invoke($generateCommand, $string);
         };
 
-        self::assertSame('', $sujet(null));
-        self::assertSame('<![CDATA[CDATA]]>', $sujet('CDATA'));
-        self::assertSame('<![CDATA[]]]]>', $sujet(']]'));
-        self::assertSame('<![CDATA[ with terminator "]]>]]&gt;<![CDATA[" inside ]]>', $sujet(' with terminator "]]>" inside '));
-        self::assertSame(']]&gt;<![CDATA[ at the start ]]>', $sujet(']]> at the start '));
-        self::assertSame('<![CDATA[ at the end ]]>]]&gt;', $sujet(' at the end ]]>'));
+        $this->assertSame('', $sujet(null));
+        $this->assertSame('<![CDATA[CDATA]]>', $sujet('CDATA'));
+        $this->assertSame('<![CDATA[]]]]>', $sujet(']]'));
+        $this->assertSame('<![CDATA[ with terminator "]]>]]&gt;<![CDATA[" inside ]]>', $sujet(' with terminator "]]>" inside '));
+        $this->assertSame(']]&gt;<![CDATA[ at the start ]]>', $sujet(']]> at the start '));
+        $this->assertSame('<![CDATA[ at the end ]]>]]&gt;', $sujet(' at the end ]]>'));
     }
 
-    public function tearDown(): void
+    protected function tearDown(): void
     {
         if (file_exists($this->configFile)) {
             unlink($this->configFile);
@@ -452,6 +441,7 @@ public function tearDown(): void
         if (file_exists(sprintf('%s/local.xml.template', dirname($this->configFile)))) {
             unlink(sprintf('%s/local.xml.template', dirname($this->configFile)));
         }
+
         rmdir(dirname($this->configFile));
     }
 }
diff --git a/tests/N98/Magento/Command/MagentoConnect/ListExtensionsCommandTest.php b/tests/N98/Magento/Command/MagentoConnect/ListExtensionsCommandTest.php
index cd053aebe..5c7beb7d4 100644
--- a/tests/N98/Magento/Command/MagentoConnect/ListExtensionsCommandTest.php
+++ b/tests/N98/Magento/Command/MagentoConnect/ListExtensionsCommandTest.php
@@ -1,12 +1,14 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\MagentoConnect;
 
 use Mage;
 use N98\Magento\Command\TestCase;
 use Symfony\Component\Console\Tester\CommandTester;
 
-class ListExtensionsCommandTest extends TestCase
+final class ListExtensionsCommandTest extends TestCase
 {
     public function testExecute()
     {
@@ -22,6 +24,7 @@ public function testExecute()
 
         $application = $this->getApplication();
         $application->add(new ListExtensionsCommand());
+
         $command = $this->getApplication()->find('extension:list');
 
         $commandTester = new CommandTester($command);
@@ -29,8 +32,8 @@ public function testExecute()
             ['command' => $command->getName(), 'search'  => 'Mage_All_Latest'],
         );
 
-        self::assertContains('Package', $commandTester->getDisplay());
-        self::assertContains('Version', $commandTester->getDisplay());
-        self::assertContains('Mage_All_Latest', $commandTester->getDisplay());
+        $this->assertContains('Package', $commandTester->getDisplay());
+        $this->assertContains('Version', $commandTester->getDisplay());
+        $this->assertContains('Mage_All_Latest', $commandTester->getDisplay());
     }
 }
diff --git a/tests/N98/Magento/Command/MagentoConnect/ValidateExtensionCommandTest.php b/tests/N98/Magento/Command/MagentoConnect/ValidateExtensionCommandTest.php
index 9f0fd0655..4174767c7 100644
--- a/tests/N98/Magento/Command/MagentoConnect/ValidateExtensionCommandTest.php
+++ b/tests/N98/Magento/Command/MagentoConnect/ValidateExtensionCommandTest.php
@@ -1,12 +1,14 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\MagentoConnect;
 
 use Mage;
 use N98\Magento\Command\TestCase;
 use Symfony\Component\Console\Tester\CommandTester;
 
-class ValidateExtensionCommandTest extends TestCase
+final class ValidateExtensionCommandTest extends TestCase
 {
     public function testSetup()
     {
@@ -39,6 +41,6 @@ public function testSetup()
         );
 
         $output = $commandTester->getDisplay();
-        self::assertContains('Mage_All_Latest', $output);
+        $this->assertContains('Mage_All_Latest', $output);
     }
 }
diff --git a/tests/N98/Magento/Command/Media/DumpCommand.php b/tests/N98/Magento/Command/Media/DumpCommand.php
index de3da5900..b2d6d134d 100644
--- a/tests/N98/Magento/Command/Media/DumpCommand.php
+++ b/tests/N98/Magento/Command/Media/DumpCommand.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\Media;
 
 use N98\Magento\Command\TestCase;
@@ -11,6 +13,7 @@ public function testExecute()
     {
         $application = $this->getApplication();
         $application->add(new DumpCommand());
+
         $command = $this->getApplication()->find('media:dump');
 
         $commandTester = new CommandTester($command);
diff --git a/tests/N98/Magento/Command/Script/Repository/ListCommandTest.php b/tests/N98/Magento/Command/Script/Repository/ListCommandTest.php
index a78170a96..ae2944b41 100644
--- a/tests/N98/Magento/Command/Script/Repository/ListCommandTest.php
+++ b/tests/N98/Magento/Command/Script/Repository/ListCommandTest.php
@@ -1,11 +1,13 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\Script\Repository;
 
 use N98\Magento\Command\TestCase;
 use Symfony\Component\Console\Tester\CommandTester;
 
-class ListCommandTest extends TestCase
+final class ListCommandTest extends TestCase
 {
     public function testExecute()
     {
@@ -15,6 +17,7 @@ public function testExecute()
         $application->setConfig($config);
 
         $application->add(new RunCommand());
+
         $command = $this->getApplication()->find('script:repo:list');
 
         $commandTester = new CommandTester($command);
@@ -22,8 +25,8 @@ public function testExecute()
             ['command' => $command->getName()],
         );
 
-        self::assertStringContainsString('Cache Flush Command Test (Hello World)', $commandTester->getDisplay());
-        self::assertStringContainsString('Foo command', $commandTester->getDisplay());
-        self::assertStringContainsString('Bar command', $commandTester->getDisplay());
+        $this->assertStringContainsString('Cache Flush Command Test (Hello World)', $commandTester->getDisplay());
+        $this->assertStringContainsString('Foo command', $commandTester->getDisplay());
+        $this->assertStringContainsString('Bar command', $commandTester->getDisplay());
     }
 }
diff --git a/tests/N98/Magento/Command/Script/Repository/RunCommandTest.php b/tests/N98/Magento/Command/Script/Repository/RunCommandTest.php
index 033ef10b9..cf48c7251 100644
--- a/tests/N98/Magento/Command/Script/Repository/RunCommandTest.php
+++ b/tests/N98/Magento/Command/Script/Repository/RunCommandTest.php
@@ -1,11 +1,13 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\Script\Repository;
 
 use N98\Magento\Command\TestCase;
 use Symfony\Component\Console\Tester\CommandTester;
 
-class RunCommandTest extends TestCase
+final class RunCommandTest extends TestCase
 {
     public function testExecute()
     {
@@ -18,6 +20,7 @@ public function testExecute()
         $application->setConfig($config);
 
         $application->add(new RunCommand());
+
         $command = $this->getApplication()->find('script:repo:run');
 
         $commandTester = new CommandTester($command);
@@ -26,12 +29,9 @@ public function testExecute()
         );
 
         // Runs sys:info -> Check for any output
-        self::assertStringContainsString('Vendors (core)', $commandTester->getDisplay());
+        $this->assertStringContainsString('Vendors (core)', $commandTester->getDisplay());
 
-        self::assertStringContainsString(
-            $testDir . '/hello-world.magerun',
-            $this->normalizePathSeparators($commandTester->getDisplay()),
-        );
+        $this->assertStringContainsString($testDir . '/hello-world.magerun', $this->normalizePathSeparators($commandTester->getDisplay()));
     }
 
     /**
diff --git a/tests/N98/Magento/Command/ScriptCommandTest.php b/tests/N98/Magento/Command/ScriptCommandTest.php
index cfb4a9baa..34859f059 100644
--- a/tests/N98/Magento/Command/ScriptCommandTest.php
+++ b/tests/N98/Magento/Command/ScriptCommandTest.php
@@ -1,17 +1,20 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command;
 
 use Mage;
 use Symfony\Component\Console\Tester\CommandTester;
 
-class ScriptCommandTest extends TestCase
+final class ScriptCommandTest extends TestCase
 {
     public function testExecute()
     {
         $application = $this->getApplication();
         $application->add(new ScriptCommand());
         $application->setAutoExit(false);
+
         $command = $this->getApplication()->find('script');
 
         $commandTester = new CommandTester($command);
@@ -21,17 +24,17 @@ public function testExecute()
 
         // Check pre defined vars
         $edition = is_callable(['\Mage', 'getEdition']) ? Mage::getEdition() : 'Community';
-        self::assertStringContainsString('magento.edition: ' . $edition, $commandTester->getDisplay());
-
-        self::assertStringContainsString('magento.root: ' . $this->getApplication()->getMagentoRootFolder(), $commandTester->getDisplay());
-        self::assertStringContainsString('magento.version: ' . Mage::getVersion(), $commandTester->getDisplay());
-        self::assertStringContainsString('magerun.version: ' . $this->getApplication()->getVersion(), $commandTester->getDisplay());
-
-        self::assertStringContainsString('code', $commandTester->getDisplay());
-        self::assertStringContainsString('foo.sql', $commandTester->getDisplay());
-        self::assertStringContainsString('BAR: foo.sql.gz', $commandTester->getDisplay());
-        self::assertStringContainsString('Magento Websites', $commandTester->getDisplay());
-        self::assertStringContainsString('web/secure/base_url', $commandTester->getDisplay());
-        self::assertStringContainsString('web/seo/use_rewrites => 1', $commandTester->getDisplay());
+        $this->assertStringContainsString('magento.edition: ' . $edition, $commandTester->getDisplay());
+
+        $this->assertStringContainsString('magento.root: ' . $this->getApplication()->getMagentoRootFolder(), $commandTester->getDisplay());
+        $this->assertStringContainsString('magento.version: ' . Mage::getVersion(), $commandTester->getDisplay());
+        $this->assertStringContainsString('magerun.version: ' . $this->getApplication()->getVersion(), $commandTester->getDisplay());
+
+        $this->assertStringContainsString('code', $commandTester->getDisplay());
+        $this->assertStringContainsString('foo.sql', $commandTester->getDisplay());
+        $this->assertStringContainsString('BAR: foo.sql.gz', $commandTester->getDisplay());
+        $this->assertStringContainsString('Magento Websites', $commandTester->getDisplay());
+        $this->assertStringContainsString('web/secure/base_url', $commandTester->getDisplay());
+        $this->assertStringContainsString('web/seo/use_rewrites => 1', $commandTester->getDisplay());
     }
 }
diff --git a/tests/N98/Magento/Command/System/Check/Settings/CookieDomainCheckAbstractTest.php b/tests/N98/Magento/Command/System/Check/Settings/CookieDomainCheckAbstractTest.php
index 3fe1f04e2..ecc4d174d 100644
--- a/tests/N98/Magento/Command/System/Check/Settings/CookieDomainCheckAbstractTest.php
+++ b/tests/N98/Magento/Command/System/Check/Settings/CookieDomainCheckAbstractTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 /**
  * this file is part of magerun
  *
@@ -15,51 +17,48 @@
  *
  * @covers N98\Magento\Command\System\Check\Settings\CookieDomainCheckAbstract
  */
-class CookieDomainCheckAbstractTest extends TestCase
+final class CookieDomainCheckAbstractTest extends TestCase
 {
     /**
      * @see validateCookieDomainAgainstUrl
      */
-    public function provideCookieDomainsAndBaseUrls()
+    public function provideCookieDomainsAndBaseUrls(): \Iterator
     {
-        return [
-            ['', '', false],
-            ['https://www.example.com/', '', false],
-            ['', '.example.com', false],
-            ['https://www.example.com/', '.example.com', true],
-            ['https://www.example.com/', 'www.example.com', true],
-            ['https://images.example.com/', 'www.example.com', false],
-            ['https://images.example.com/', 'example.com', true],
-            ['https://images.example.com/', '.example.com', true],
-            ['https://example.com/', '.example.com', false],
-            ['https://www.example.com/', '.www.example.com', false],
-            ['https://www.example.com/', 'wwww.example.com', false],
-            ['https://www.example.com/', 'ww.example.com', false],
-            ['https://www.example.com/', '.ww.example.com', false],
-            ['https://www.example.com/', '.w.example.com', false],
-            ['https://www.example.com/', '..example.com', false],
-            // false-positives we know about, there is no check against public suffix list (the co.uk check)
-            ['https://www.example.com/', '.com', false],
-            ['https://www.example.co.uk/', '.co.uk', true],
-            ['https://www.example.co.uk/', 'co.uk', true],
-            // go cases <http://gertjans.home.xs4all.nl/javascript/cookies.html>
-            ['http://go/', 'go', false],
-            ['http://go/', '.go', false],
-            ['http://go.go/', 'go', false],
-            ['http://go.go/', '.go', false],
-            # ... some edge-cases left out
-            ['http://www.good.go/', '.good.go', true],
-            ['http://www.good.go/', 'www.good.go', true],
-            ['http://good.go/', 'www.good.go', false],
-            ['http://also.good.go/', 'www.good.go', false],
-        ];
+        yield ['', '', false];
+        yield ['https://www.example.com/', '', false];
+        yield ['', '.example.com', false];
+        yield ['https://www.example.com/', '.example.com', true];
+        yield ['https://www.example.com/', 'www.example.com', true];
+        yield ['https://images.example.com/', 'www.example.com', false];
+        yield ['https://images.example.com/', 'example.com', true];
+        yield ['https://images.example.com/', '.example.com', true];
+        yield ['https://example.com/', '.example.com', false];
+        yield ['https://www.example.com/', '.www.example.com', false];
+        yield ['https://www.example.com/', 'wwww.example.com', false];
+        yield ['https://www.example.com/', 'ww.example.com', false];
+        yield ['https://www.example.com/', '.ww.example.com', false];
+        yield ['https://www.example.com/', '.w.example.com', false];
+        yield ['https://www.example.com/', '..example.com', false];
+        // false-positives we know about, there is no check against public suffix list (the co.uk check)
+        yield ['https://www.example.com/', '.com', false];
+        yield ['https://www.example.co.uk/', '.co.uk', true];
+        yield ['https://www.example.co.uk/', 'co.uk', true];
+        // go cases <http://gertjans.home.xs4all.nl/javascript/cookies.html>
+        yield ['http://go/', 'go', false];
+        yield ['http://go/', '.go', false];
+        yield ['http://go.go/', 'go', false];
+        yield ['http://go.go/', '.go', false];
+        # ... some edge-cases left out
+        yield ['http://www.good.go/', '.good.go', true];
+        yield ['http://www.good.go/', 'www.good.go', true];
+        yield ['http://good.go/', 'www.good.go', false];
+        yield ['http://also.good.go/', 'www.good.go', false];
     }
 
     /**
-     * @test
      * @dataProvider provideCookieDomainsAndBaseUrls
      */
-    public function validateCookieDomainAgainstUrl($baseUrl, $cookieDomain, $expected)
+    public function testValidateCookieDomainAgainstUrl($baseUrl, $cookieDomain, $expected)
     {
         /** @var CookieDomainCheckAbstract $stub */
         $stub = $this->getMockForAbstractClass(__NAMESPACE__ . '\CookieDomainCheckAbstract');
@@ -68,6 +67,6 @@ public function validateCookieDomainAgainstUrl($baseUrl, $cookieDomain, $expecte
 
         $message = sprintf('%s for %s', $cookieDomain, $baseUrl);
 
-        self::assertSame($expected, $actual, $message);
+        $this->assertSame($expected, $actual, $message);
     }
 }
diff --git a/tests/N98/Magento/Command/System/CheckCommandTest.php b/tests/N98/Magento/Command/System/CheckCommandTest.php
index 614cc360d..7ec36142c 100644
--- a/tests/N98/Magento/Command/System/CheckCommandTest.php
+++ b/tests/N98/Magento/Command/System/CheckCommandTest.php
@@ -1,25 +1,28 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\System;
 
 use N98\Magento\Command\TestCase;
 use Symfony\Component\Console\Tester\CommandTester;
 
-class CheckCommandTest extends TestCase
+final class CheckCommandTest extends TestCase
 {
     public function testExecute()
     {
         $application = $this->getApplication();
         $application->add(new InfoCommand());
+
         $command = $this->getApplication()->find('sys:check');
 
         $commandTester = new CommandTester($command);
         $commandTester->execute(['command' => $command->getName()]);
 
-        self::assertMatchesRegularExpression('/SETTINGS/', $commandTester->getDisplay());
-        self::assertMatchesRegularExpression('/FILESYSTEM/', $commandTester->getDisplay());
-        self::assertMatchesRegularExpression('/PHP/', $commandTester->getDisplay());
-        self::assertMatchesRegularExpression('/SECURITY/', $commandTester->getDisplay());
-        self::assertMatchesRegularExpression('/MYSQL/', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression('/SETTINGS/', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression('/FILESYSTEM/', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression('/PHP/', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression('/SECURITY/', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression('/MYSQL/', $commandTester->getDisplay());
     }
 }
diff --git a/tests/N98/Magento/Command/System/Cron/HistoryCommandTest.php b/tests/N98/Magento/Command/System/Cron/HistoryCommandTest.php
index 943ec4c3f..ddc2d9eea 100644
--- a/tests/N98/Magento/Command/System/Cron/HistoryCommandTest.php
+++ b/tests/N98/Magento/Command/System/Cron/HistoryCommandTest.php
@@ -1,16 +1,19 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\System\Cron;
 
 use N98\Magento\Command\TestCase;
 use Symfony\Component\Console\Tester\CommandTester;
 
-class HistoryCommandTest extends TestCase
+final class HistoryCommandTest extends TestCase
 {
     public function testExecute()
     {
         $application = $this->getApplication();
         $application->add(new ListCommand());
+
         $command = $this->getApplication()->find('sys:cron:history');
 
         $commandTester = new CommandTester($command);
@@ -18,6 +21,6 @@ public function testExecute()
             ['command' => $command->getName()],
         );
 
-        self::assertMatchesRegularExpression('/Last executed jobs/', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression('/Last executed jobs/', $commandTester->getDisplay());
     }
 }
diff --git a/tests/N98/Magento/Command/System/Cron/ListCommandTest.php b/tests/N98/Magento/Command/System/Cron/ListCommandTest.php
index 82f80c1d2..d0f7f47f4 100644
--- a/tests/N98/Magento/Command/System/Cron/ListCommandTest.php
+++ b/tests/N98/Magento/Command/System/Cron/ListCommandTest.php
@@ -1,21 +1,24 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\System\Cron;
 
 use N98\Magento\Command\TestCase;
 use Symfony\Component\Console\Tester\CommandTester;
 
-class ListCommandTest extends TestCase
+final class ListCommandTest extends TestCase
 {
     public function testExecute()
     {
         $application = $this->getApplication();
         $application->add(new ListCommand());
+
         $command = $this->getApplication()->find('sys:cron:list');
 
         $commandTester = new CommandTester($command);
         $commandTester->execute(['command' => $command->getName()]);
 
-        self::assertMatchesRegularExpression('/Cronjob List/', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression('/Cronjob List/', $commandTester->getDisplay());
     }
 }
diff --git a/tests/N98/Magento/Command/System/Cron/RunCommandTest.php b/tests/N98/Magento/Command/System/Cron/RunCommandTest.php
index 024f7be23..1d7efbbf5 100644
--- a/tests/N98/Magento/Command/System/Cron/RunCommandTest.php
+++ b/tests/N98/Magento/Command/System/Cron/RunCommandTest.php
@@ -1,16 +1,19 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\System\Cron;
 
 use N98\Magento\Command\TestCase;
 use Symfony\Component\Console\Tester\CommandTester;
 
-class RunCommandTest extends TestCase
+final class RunCommandTest extends TestCase
 {
     public function testExecute()
     {
         $application = $this->getApplication();
         $application->add(new ListCommand());
+
         $command = $this->getApplication()->find('sys:cron:run');
 
         $commandTester = new CommandTester($command);
@@ -18,16 +21,14 @@ public function testExecute()
             ['command' => $command->getName(), 'job'     => 'log_clean'],
         );
 
-        self::assertMatchesRegularExpression('/Run Mage_Log_Model_Cron::logClean done/', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression('/Run Mage_Log_Model_Cron::logClean done/', $commandTester->getDisplay());
     }
 
-    /**
-     * @test
-     */
-    public function urlBuildingWhileCron()
+    public function testUrlBuildingWhileCron()
     {
         $application = $this->getApplication();
         $application->add(new RunCommand());
+
         $command = $this->getApplication()->find('sys:cron:run');
 
         $commandTester = new CommandTester($command);
@@ -35,6 +36,6 @@ public function urlBuildingWhileCron()
             ['command' => $command->getName(), 'job'     => 'log_clean'],
         );
 
-        self::assertMatchesRegularExpression('/Run Mage_Log_Model_Cron::logClean done/', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression('/Run Mage_Log_Model_Cron::logClean done/', $commandTester->getDisplay());
     }
 }
diff --git a/tests/N98/Magento/Command/System/Cron/ServerEnvironmentTest.php b/tests/N98/Magento/Command/System/Cron/ServerEnvironmentTest.php
index ff7cb3a96..01bc2a9ec 100644
--- a/tests/N98/Magento/Command/System/Cron/ServerEnvironmentTest.php
+++ b/tests/N98/Magento/Command/System/Cron/ServerEnvironmentTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\System\Cron;
 
 use N98\Magento\Application;
@@ -7,7 +9,7 @@
 use Mage_Core_Model_Store;
 use N98\Magento\Command\TestCase;
 
-class ServerEnvironmentTest extends TestCase
+final class ServerEnvironmentTest extends TestCase
 {
     protected function setUp(): void
     {
@@ -15,41 +17,35 @@ protected function setUp(): void
 
         // Initialise Magento autoloader (if not yet)
         $application = $this->getApplication();
-        self::assertInstanceOf(Application::class, $application);
+        $this->assertInstanceOf(Application::class, $application);
     }
 
-    /**
-     * @test that getBaseUrl contains the script-name (here: Phpunit runner)
-     */
-    public function regression()
+    public function testRegression()
     {
         $store = Mage::app()->getStore(null);
         $actual = $store->getBaseUrl(Mage_Core_Model_Store::URL_TYPE_LINK);
-        self::assertIsString($actual);
-        self::assertMatchesRegularExpression('~/(ide-phpunit.php|phpunit)/$~', $actual);
+        $this->assertIsString($actual);
+        $this->assertMatchesRegularExpression('~/(ide-phpunit.php|phpunit)/$~', $actual);
     }
 
-    /**
-     * @test
-     */
-    public function environmentFix()
+    public function testEnvironmentFix()
     {
         $store = Mage::app()->getStore(null);
         $store->resetConfig();
 
-        $environment = new ServerEnvironment();
-        $environment->initalize();
+        $serverEnvironment = new ServerEnvironment();
+        $serverEnvironment->initalize();
 
         $actual = $store->getBaseUrl(Mage_Core_Model_Store::URL_TYPE_LINK);
-        self::assertIsString($actual);
-        self::assertStringEndsWith('/index.php/', $actual);
+        $this->assertIsString($actual);
+        $this->assertStringEndsWith('/index.php/', $actual);
 
         $store->resetConfig();
 
-        $environment->reset();
+        $serverEnvironment->reset();
 
         $actual = Mage::app()->getStore(null)->getBaseUrl(Mage_Core_Model_Store::URL_TYPE_LINK);
-        self::assertIsString($actual);
-        self::assertMatchesRegularExpression('~/(ide-phpunit.php|phpunit)/$~', $actual);
+        $this->assertIsString($actual);
+        $this->assertMatchesRegularExpression('~/(ide-phpunit.php|phpunit)/$~', $actual);
     }
 }
diff --git a/tests/N98/Magento/Command/System/InfoCommandTest.php b/tests/N98/Magento/Command/System/InfoCommandTest.php
index 9586bd5d8..17807476e 100644
--- a/tests/N98/Magento/Command/System/InfoCommandTest.php
+++ b/tests/N98/Magento/Command/System/InfoCommandTest.php
@@ -1,24 +1,27 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\System;
 
 use N98\Magento\Command\TestCase;
 use Symfony\Component\Console\Tester\CommandTester;
 
-class InfoCommandTest extends TestCase
+final class InfoCommandTest extends TestCase
 {
     public function testExecute()
     {
         $application = $this->getApplication();
         $application->add(new InfoCommand());
+
         $command = $this->getApplication()->find('sys:info');
 
         $commandTester = new CommandTester($command);
         $commandTester->execute(['command' => $command->getName()]);
 
-        self::assertMatchesRegularExpression('/Magento System Information/', $commandTester->getDisplay());
-        self::assertMatchesRegularExpression('/Install Date/', $commandTester->getDisplay());
-        self::assertMatchesRegularExpression('/Crypt Key/', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression('/Magento System Information/', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression('/Install Date/', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression('/Crypt Key/', $commandTester->getDisplay());
 
         // Settings argument
         $commandTester->execute(
@@ -26,6 +29,6 @@ public function testExecute()
         );
 
         $commandResult = $commandTester->getDisplay();
-        self::assertMatchesRegularExpression('/\d+\.\d+\.\d+/', $commandResult);
+        $this->assertMatchesRegularExpression('/\d+\.\d+\.\d+/', $commandResult);
     }
 }
diff --git a/tests/N98/Magento/Command/System/MaintenanceCommandTest.php b/tests/N98/Magento/Command/System/MaintenanceCommandTest.php
index e8fea36bf..10047f40d 100644
--- a/tests/N98/Magento/Command/System/MaintenanceCommandTest.php
+++ b/tests/N98/Magento/Command/System/MaintenanceCommandTest.php
@@ -1,16 +1,19 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\System;
 
 use N98\Magento\Command\TestCase;
 use Symfony\Component\Console\Tester\CommandTester;
 
-class MaintenanceCommandTest extends TestCase
+final class MaintenanceCommandTest extends TestCase
 {
     public function testExecute()
     {
         $application = $this->getApplication();
         $application->add(new MaintenanceCommand());
+
         $command = $application->find('sys:maintenance');
 
         $magentoRootFolder = $application->getMagentoRootFolder();
@@ -22,13 +25,13 @@ public function testExecute()
         $commandTester->execute(
             ['command' => $command->getName(), '--on'    => ''],
         );
-        self::assertMatchesRegularExpression('/Maintenance mode on/', $commandTester->getDisplay());
-        self::assertFileExists($magentoRootFolder . '/maintenance.flag');
+        $this->assertMatchesRegularExpression('/Maintenance mode on/', $commandTester->getDisplay());
+        $this->assertFileExists($magentoRootFolder . '/maintenance.flag');
 
         $commandTester->execute(
             ['command' => $command->getName(), '--off'   => ''],
         );
-        self::assertMatchesRegularExpression('/Maintenance mode off/', $commandTester->getDisplay());
-        self::assertFileDoesNotExist($magentoRootFolder . '/maintenance.flag');
+        $this->assertMatchesRegularExpression('/Maintenance mode off/', $commandTester->getDisplay());
+        $this->assertFileDoesNotExist($magentoRootFolder . '/maintenance.flag');
     }
 }
diff --git a/tests/N98/Magento/Command/System/Setup/ChangeVersionCommandTest.php b/tests/N98/Magento/Command/System/Setup/ChangeVersionCommandTest.php
index 7bbe15253..e2fd29c1d 100644
--- a/tests/N98/Magento/Command/System/Setup/ChangeVersionCommandTest.php
+++ b/tests/N98/Magento/Command/System/Setup/ChangeVersionCommandTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\System\Setup;
 
 use InvalidArgumentException;
@@ -7,7 +9,7 @@
 use N98\Magento\Command\TestCase;
 use Symfony\Component\Console\Tester\CommandTester;
 
-class ChangeVersionCommandTest extends TestCase
+final class ChangeVersionCommandTest extends TestCase
 {
     public function testChangeVersion()
     {
@@ -20,26 +22,24 @@ public function testChangeVersion()
             ->getMock();
 
         $resourceModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('setDbVersion')
             ->with('weee_setup', '1.6.0.0');
 
         $resourceModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('setDataVersion')
             ->with('weee_setup', '1.6.0.0');
 
         $application = $this->getApplication();
         $application->add($command);
+
         $command = $this->getApplication()->find('sys:setup:change-version');
 
         $commandTester = new CommandTester($command);
         $commandTester->execute(['command'   => $command->getName(), 'module'    => 'Mage_Weee', 'version'   => '1.6.0.0']);
 
-        self::assertStringContainsString(
-            'Successfully updated: "Mage_Weee" - "weee_setup" to version: "1.6.0.0"',
-            $commandTester->getDisplay(),
-        );
+        $this->assertStringContainsString('Successfully updated: "Mage_Weee" - "weee_setup" to version: "1.6.0.0"', $commandTester->getDisplay());
     }
 
     public function testUpdateBySetupName()
@@ -53,37 +53,36 @@ public function testUpdateBySetupName()
             ->getMock();
 
         $command
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('_getResourceSingleton')
             ->willReturn($resourceModel);
 
         $resourceModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('setDbVersion')
             ->with('weee_setup', '1.6.0.0');
 
         $resourceModel
-            ->expects(self::once())
+            ->expects($this->once())
             ->method('setDataVersion')
             ->with('weee_setup', '1.6.0.0');
 
         $application = $this->getApplication();
         $application->add($command);
+
         $command = $this->getApplication()->find('sys:setup:change-version');
 
         $commandTester = new CommandTester($command);
         $commandTester->execute(['command'   => $command->getName(), 'module'    => 'Mage_Weee', 'version'   => '1.6.0.0', 'setup'     => 'weee_setup']);
 
-        self::assertStringContainsString(
-            'Successfully updated: "Mage_Weee" - "weee_setup" to version: "1.6.0.0"',
-            $commandTester->getDisplay(),
-        );
+        $this->assertStringContainsString('Successfully updated: "Mage_Weee" - "weee_setup" to version: "1.6.0.0"', $commandTester->getDisplay());
     }
 
     public function testSetupNameNotFound()
     {
         $application = $this->getApplication();
         $application->add(new ChangeVersionCommand());
+
         $command = $this->getApplication()->find('sys:setup:change-version');
 
         $commandTester = new CommandTester($command);
@@ -99,6 +98,7 @@ public function testModuleDoesNotExist()
     {
         $application = $this->getApplication();
         $application->add(new ChangeVersionCommand());
+
         $command = $this->getApplication()->find('sys:setup:change-version');
 
         $commandTester = new CommandTester($command);
@@ -113,21 +113,19 @@ public function testCommandReturnsEarlyIfNoSetupResourcesForModule()
             ->setMethods(['getModuleSetupResources'])
             ->getMock();
 
-        $command->expects(self::once())
+        $command->expects($this->once())
             ->method('getModuleSetupResources')
             ->with('Mage_Weee')
             ->willReturn([]);
 
         $application = $this->getApplication();
         $application->add($command);
+
         $command = $this->getApplication()->find('sys:setup:change-version');
 
         $commandTester = new CommandTester($command);
         $commandTester->execute(['command'   => $command->getName(), 'module'    => 'Mage_Weee', 'version'   => '1.0.0.0', 'setup'     => 'weee_setup']);
 
-        self::assertStringContainsString(
-            'No setup resources found for module: "Mage_Weee"',
-            $commandTester->getDisplay(),
-        );
+        $this->assertStringContainsString('No setup resources found for module: "Mage_Weee"', $commandTester->getDisplay());
     }
 }
diff --git a/tests/N98/Magento/Command/System/Setup/CompareVersionsCommandTest.php b/tests/N98/Magento/Command/System/Setup/CompareVersionsCommandTest.php
index d13d86499..bf03d64e9 100644
--- a/tests/N98/Magento/Command/System/Setup/CompareVersionsCommandTest.php
+++ b/tests/N98/Magento/Command/System/Setup/CompareVersionsCommandTest.php
@@ -1,17 +1,20 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\System\Setup;
 
 use N98\Magento\Command\TestCase;
 use org\bovigo\vfs\vfsStream;
 use Symfony\Component\Console\Tester\CommandTester;
 
-class CompareVersionsCommandTest extends TestCase
+final class CompareVersionsCommandTest extends TestCase
 {
     public function testExecute()
     {
         $application = $this->getApplication();
         $application->add(new CompareVersionsCommand());
+
         $command = $this->getApplication()->find('sys:setup:compare-versions');
 
         $commandTester = new CommandTester($command);
@@ -19,11 +22,11 @@ public function testExecute()
             ['command' => $command->getName()],
         );
 
-        self::assertMatchesRegularExpression('/Setup/', $commandTester->getDisplay());
-        self::assertMatchesRegularExpression('/Module/', $commandTester->getDisplay());
-        self::assertMatchesRegularExpression('/DB/', $commandTester->getDisplay());
-        self::assertMatchesRegularExpression('/Data/', $commandTester->getDisplay());
-        self::assertMatchesRegularExpression('/Status/', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression('/Setup/', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression('/Module/', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression('/DB/', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression('/Data/', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression('/Status/', $commandTester->getDisplay());
     }
 
     public function testJunit()
@@ -31,6 +34,7 @@ public function testJunit()
         vfsStream::setup();
         $application = $this->getApplication();
         $application->add(new CompareVersionsCommand());
+
         $command = $this->getApplication()->find('sys:setup:compare-versions');
 
         $commandTester = new CommandTester($command);
@@ -38,6 +42,6 @@ public function testJunit()
             ['command'     => $command->getName(), '--log-junit' => vfsStream::url('root/junit.xml')],
         );
 
-        self::assertFileExists(vfsStream::url('root/junit.xml'));
+        $this->assertFileExists(vfsStream::url('root/junit.xml'));
     }
 }
diff --git a/tests/N98/Magento/Command/System/Setup/IncrementalCommandStub.php b/tests/N98/Magento/Command/System/Setup/IncrementalCommandStub.php
index 66edb7616..0f416e70d 100644
--- a/tests/N98/Magento/Command/System/Setup/IncrementalCommandStub.php
+++ b/tests/N98/Magento/Command/System/Setup/IncrementalCommandStub.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 /**
  * this file is part of magerun
  *
@@ -14,7 +16,7 @@
 class IncrementalCommandStub extends IncrementalCommand
 {
     /** @noinspection MagicMethodsValidityInspection */
-    public function __construct($name = null)
+    public function __construct()
     {
         // missing parent constructor call by intention
     }
diff --git a/tests/N98/Magento/Command/System/Setup/IncrementalCommandTest.php b/tests/N98/Magento/Command/System/Setup/IncrementalCommandTest.php
index f547589ef..6e5a40805 100644
--- a/tests/N98/Magento/Command/System/Setup/IncrementalCommandTest.php
+++ b/tests/N98/Magento/Command/System/Setup/IncrementalCommandTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\System\Setup;
 
 use N98\Magento\Command\TestCase;
@@ -8,25 +10,24 @@
  * Class IncrementalCommandTest
  *
  * @package N98\Magento\Command\System\Setup
- * @covers  N98\Magento\Command\System\Setup\IncrementalCommand
+ * @covers  \N98\Magento\Command\System\Setup\IncrementalCommand
  */
-class IncrementalCommandTest extends TestCase
+final class IncrementalCommandTest extends TestCase
 {
     /**
-     * @test
      * @link https://github.com/netz98/n98-magerun/pull/747
      */
-    public function regression747()
+    public function testRegression747()
     {
-        $stub = new IncrementalCommandStub();
+        $incrementalCommandStub = new IncrementalCommandStub();
 
-        $actual = $stub->callProtectedMethodFromObject('protectedMethod', $this, ['fooBar']);
-        self::assertSame('barBaz', $actual);
+        $actual = $incrementalCommandStub->callProtectedMethodFromObject('protectedMethod', $this, ['fooBar']);
+        $this->assertSame('barBaz', $actual);
     }
 
-    protected function protectedMethod($arg)
+    protected function protectedMethod($arg): string
     {
-        self::assertSame('fooBar', $arg);
+        $this->assertSame('fooBar', $arg);
         $this->addToAssertionCount(1);
 
         return 'barBaz';
diff --git a/tests/N98/Magento/Command/System/Setup/RemoveCommandTest.php b/tests/N98/Magento/Command/System/Setup/RemoveCommandTest.php
index 650ad36e4..0e0ffdf73 100644
--- a/tests/N98/Magento/Command/System/Setup/RemoveCommandTest.php
+++ b/tests/N98/Magento/Command/System/Setup/RemoveCommandTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\System\Setup;
 
 use InvalidArgumentException;
@@ -13,7 +15,7 @@
  * @package N98\Magento\Command\System\Setup
  * @author Aydin Hassan <aydin@hotmail.co.uk>
  */
-class RemoveCommandTest extends TestCase
+final class RemoveCommandTest extends TestCase
 {
     public function testRemoveModule()
     {
@@ -22,14 +24,14 @@ public function testRemoveModule()
             ->setMethods(['delete'])
             ->getMock();
 
-        $mockAdapter->expects(self::once())
+        $mockAdapter->expects($this->once())
             ->method('delete')
             ->willReturn(1);
 
         $coreResource = $this->getMockBuilder(Mage_Core_Model_Resource::class)
             ->getMock();
 
-        $coreResource->expects(self::once())
+        $coreResource->expects($this->once())
             ->method('getConnection')
             ->willReturn($mockAdapter);
 
@@ -37,21 +39,19 @@ public function testRemoveModule()
             ->setMethods(['getMageCoreResource'])
             ->getMock();
 
-        $command->expects(self::once())
+        $command->expects($this->once())
             ->method('getMageCoreResource')
             ->willReturn($coreResource);
 
         $application = $this->getApplication();
         $application->add($command);
+
         $command = $this->getApplication()->find('sys:setup:remove');
 
         $commandTester = new CommandTester($command);
         $commandTester->execute(['command'   => $command->getName(), 'module'    => 'Mage_Weee']);
 
-        self::assertStringContainsString(
-            'Successfully removed setup resource: "weee_setup" from module: "Mage_Weee"',
-            $commandTester->getDisplay(),
-        );
+        $this->assertStringContainsString('Successfully removed setup resource: "weee_setup" from module: "Mage_Weee"', $commandTester->getDisplay());
     }
 
     public function testRemoveBySetupName()
@@ -61,14 +61,14 @@ public function testRemoveBySetupName()
             ->setMethods(['delete'])
             ->getMock();
 
-        $mockAdapter->expects(self::once())
+        $mockAdapter->expects($this->once())
             ->method('delete')
             ->willReturn(1);
 
         $coreResource = $this->getMockBuilder(Mage_Core_Model_Resource::class)
             ->getMock();
 
-        $coreResource->expects(self::once())
+        $coreResource->expects($this->once())
             ->method('getConnection')
             ->willReturn($mockAdapter);
 
@@ -76,12 +76,13 @@ public function testRemoveBySetupName()
             ->setMethods(['getMageCoreResource'])
             ->getMock();
 
-        $command->expects(self::once())
+        $command->expects($this->once())
             ->method('getMageCoreResource')
             ->willReturn($coreResource);
 
         $application = $this->getApplication();
         $application->add($command);
+
         $command = $this->getApplication()->find('sys:setup:remove');
 
         $commandTester = new CommandTester($command);
@@ -91,10 +92,7 @@ public function testRemoveBySetupName()
             'setup'     => 'weee_setup',
         ]);
 
-        self::assertStringContainsString(
-            'Successfully removed setup resource: "weee_setup" from module: "Mage_Weee"',
-            $commandTester->getDisplay(),
-        );
+        $this->assertStringContainsString('Successfully removed setup resource: "weee_setup" from module: "Mage_Weee"', $commandTester->getDisplay());
     }
 
     public function testRemoveBySetupNameFailure()
@@ -104,7 +102,7 @@ public function testRemoveBySetupNameFailure()
             ->setMethods(['delete'])
             ->getMock();
 
-        $mockAdapter->expects(self::once())
+        $mockAdapter->expects($this->once())
             ->method('delete')
             ->willReturn(0);
 
@@ -112,11 +110,11 @@ public function testRemoveBySetupNameFailure()
             ->getMock();
         ;
 
-        $coreResource->expects(self::once())
+        $coreResource->expects($this->once())
             ->method('getConnection')
             ->willReturn($mockAdapter);
 
-        $coreResource->expects(self::once())
+        $coreResource->expects($this->once())
             ->method('getTableName')
             ->with('core_resource')
             ->willReturn('core_resource');
@@ -125,27 +123,26 @@ public function testRemoveBySetupNameFailure()
             ->setMethods(['getMageCoreResource'])
             ->getMock();
 
-        $command->expects(self::once())
+        $command->expects($this->once())
             ->method('getMageCoreResource')
             ->willReturn($coreResource);
 
         $application = $this->getApplication();
         $application->add($command);
+
         $command = $this->getApplication()->find('sys:setup:remove');
 
         $commandTester = new CommandTester($command);
         $commandTester->execute(['command'   => $command->getName(), 'module'    => 'Mage_Weee', 'setup'     => 'weee_setup']);
 
-        self::assertStringContainsString(
-            'No entry was found for setup resource: "weee_setup" in module: "Mage_Weee"',
-            $commandTester->getDisplay(),
-        );
+        $this->assertStringContainsString('No entry was found for setup resource: "weee_setup" in module: "Mage_Weee"', $commandTester->getDisplay());
     }
 
     public function testSetupNameNotFound()
     {
         $application = $this->getApplication();
         $application->add(new RemoveCommand());
+
         $command = $this->getApplication()->find('sys:setup:remove');
 
         $commandTester = new CommandTester($command);
@@ -161,6 +158,7 @@ public function testModuleDoesNotExist()
     {
         $application = $this->getApplication();
         $application->add(new RemoveCommand());
+
         $command = $this->getApplication()->find('sys:setup:remove');
 
         $commandTester = new CommandTester($command);
@@ -175,13 +173,14 @@ public function testCommandReturnsEarlyIfNoSetupResourcesForModule()
             ->setMethods(['getModuleSetupResources'])
             ->getMock();
 
-        $command->expects(self::once())
+        $command->expects($this->once())
             ->method('getModuleSetupResources')
             ->with('Mage_Weee')
             ->willReturn([]);
 
         $application = $this->getApplication();
         $application->add($command);
+
         $command = $this->getApplication()->find('sys:setup:remove');
 
         $commandTester = new CommandTester($command);
@@ -191,9 +190,6 @@ public function testCommandReturnsEarlyIfNoSetupResourcesForModule()
             'setup'     => 'weee_setup',
         ]);
 
-        self::assertStringContainsString(
-            'No setup resources found for module: "Mage_Weee"',
-            $commandTester->getDisplay(),
-        );
+        $this->assertStringContainsString('No setup resources found for module: "Mage_Weee"', $commandTester->getDisplay());
     }
 }
diff --git a/tests/N98/Magento/Command/System/Setup/RunCommandTest.php b/tests/N98/Magento/Command/System/Setup/RunCommandTest.php
index c27a45c3e..8fc711047 100644
--- a/tests/N98/Magento/Command/System/Setup/RunCommandTest.php
+++ b/tests/N98/Magento/Command/System/Setup/RunCommandTest.php
@@ -1,16 +1,19 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\System\Setup;
 
 use N98\Magento\Command\TestCase;
 use Symfony\Component\Console\Tester\CommandTester;
 
-class RunCommandTest extends TestCase
+final class RunCommandTest extends TestCase
 {
     public function testExecute()
     {
         $application = $this->getApplication();
         $application->add(new CompareVersionsCommand());
+
         $command = $this->getApplication()->find('sys:setup:run');
 
         $commandTester = new CommandTester($command);
@@ -18,6 +21,6 @@ public function testExecute()
             ['command' => $command->getName()],
         );
 
-        self::assertMatchesRegularExpression('/done/', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression('/done/', $commandTester->getDisplay());
     }
 }
diff --git a/tests/N98/Magento/Command/System/Store/Config/BaseUrlListCommandTest.php b/tests/N98/Magento/Command/System/Store/Config/BaseUrlListCommandTest.php
index b392e043c..bbf95a68d 100644
--- a/tests/N98/Magento/Command/System/Store/Config/BaseUrlListCommandTest.php
+++ b/tests/N98/Magento/Command/System/Store/Config/BaseUrlListCommandTest.php
@@ -1,16 +1,19 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\System\Store\Config;
 
 use N98\Magento\Command\TestCase;
 use Symfony\Component\Console\Tester\CommandTester;
 
-class BaseUrlListCommandTest extends TestCase
+final class BaseUrlListCommandTest extends TestCase
 {
     public function testExecute()
     {
         $application = $this->getApplication();
         $application->add(new BaseUrlListCommand());
+
         $command = $this->getApplication()->find('sys:store:config:base-url:list');
 
         $commandTester = new CommandTester($command);
@@ -18,7 +21,7 @@ public function testExecute()
             ['command' => $command->getName()],
         );
 
-        self::assertMatchesRegularExpression('/secure_baseurl/', $commandTester->getDisplay());
-        self::assertMatchesRegularExpression('/unsecure_baseurl/', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression('/secure_baseurl/', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression('/unsecure_baseurl/', $commandTester->getDisplay());
     }
 }
diff --git a/tests/N98/Magento/Command/System/Store/ListCommandTest.php b/tests/N98/Magento/Command/System/Store/ListCommandTest.php
index baf953137..baee7938b 100644
--- a/tests/N98/Magento/Command/System/Store/ListCommandTest.php
+++ b/tests/N98/Magento/Command/System/Store/ListCommandTest.php
@@ -1,22 +1,25 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\System\Store;
 
 use N98\Magento\Command\TestCase;
 use Symfony\Component\Console\Tester\CommandTester;
 
-class ListCommandTest extends TestCase
+final class ListCommandTest extends TestCase
 {
     public function testExecute()
     {
         $application = $this->getApplication();
         $application->add(new ListCommand());
+
         $command = $this->getApplication()->find('sys:store:list');
 
         $commandTester = new CommandTester($command);
         $commandTester->execute(['command' => $command->getName()]);
 
-        self::assertMatchesRegularExpression('/id/', $commandTester->getDisplay());
-        self::assertMatchesRegularExpression('/code/', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression('/id/', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression('/code/', $commandTester->getDisplay());
     }
 }
diff --git a/tests/N98/Magento/Command/System/Url/ListCommandTest.php b/tests/N98/Magento/Command/System/Url/ListCommandTest.php
index 98f0f5d93..a05f6b44d 100644
--- a/tests/N98/Magento/Command/System/Url/ListCommandTest.php
+++ b/tests/N98/Magento/Command/System/Url/ListCommandTest.php
@@ -1,16 +1,19 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\System\Url;
 
 use N98\Magento\Command\TestCase;
 use Symfony\Component\Console\Tester\CommandTester;
 
-class ListCommandTest extends TestCase
+final class ListCommandTest extends TestCase
 {
     public function testExecute()
     {
         $application = $this->getApplication();
         $application->add(new ListCommand());
+
         $command = $this->getApplication()->find('sys:url:list');
 
         $commandTester = new CommandTester($command);
@@ -26,8 +29,8 @@ public function testExecute()
             ],
         );
 
-        self::assertMatchesRegularExpression('/prefix/', $commandTester->getDisplay());
-        self::assertMatchesRegularExpression('/http/', $commandTester->getDisplay());
-        self::assertMatchesRegularExpression('/suffix/', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression('/prefix/', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression('/http/', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression('/suffix/', $commandTester->getDisplay());
     }
 }
diff --git a/tests/N98/Magento/Command/System/Website/ListCommandTest.php b/tests/N98/Magento/Command/System/Website/ListCommandTest.php
index 3027e9341..9ad2c5a86 100644
--- a/tests/N98/Magento/Command/System/Website/ListCommandTest.php
+++ b/tests/N98/Magento/Command/System/Website/ListCommandTest.php
@@ -1,23 +1,26 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command\System\Website;
 
 use N98\Magento\Command\TestCase;
 use Symfony\Component\Console\Tester\CommandTester;
 
-class ListCommandTest extends TestCase
+final class ListCommandTest extends TestCase
 {
     public function testExecute()
     {
         $application = $this->getApplication();
         $application->add(new ListCommand());
+
         $command = $this->getApplication()->find('sys:website:list');
 
         $commandTester = new CommandTester($command);
         $commandTester->execute(['command' => $command->getName()]);
 
-        self::assertMatchesRegularExpression('/Magento Websites/', $commandTester->getDisplay());
-        self::assertMatchesRegularExpression('/id/', $commandTester->getDisplay());
-        self::assertMatchesRegularExpression('/code/', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression('/Magento Websites/', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression('/id/', $commandTester->getDisplay());
+        $this->assertMatchesRegularExpression('/code/', $commandTester->getDisplay());
     }
 }
diff --git a/tests/N98/Magento/Command/TestCase.php b/tests/N98/Magento/Command/TestCase.php
index 7bed51752..a04cd171b 100644
--- a/tests/N98/Magento/Command/TestCase.php
+++ b/tests/N98/Magento/Command/TestCase.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento\Command;
 
 use PHPUnit\Framework\MockObject\MockObject;
@@ -74,11 +76,7 @@ private function getTestApplication()
      */
     private function getMagerunTester($command)
     {
-        if (is_string($command)) {
-            $input = ['command' => $command];
-        } else {
-            $input = $command;
-        }
+        $input = is_string($command) ? ['command' => $command] : $command;
 
         $hash = md5(json_encode($input, JSON_THROW_ON_ERROR));
         if (!isset($this->testers[$hash])) {
@@ -97,7 +95,7 @@ protected function assertDisplayContains($command, $needle, $message = '')
     {
         $display = $this->getMagerunTester($command)->getDisplay();
 
-        self::assertStringContainsString($needle, $display, $message);
+        $this->assertStringContainsString($needle, $display, $message);
     }
 
     /**
@@ -109,7 +107,7 @@ protected function assertDisplayNotContains($command, $needle, $message = '')
     {
         $display = $this->getMagerunTester($command)->getDisplay();
 
-        self::assertStringNotContainsString($needle, $display, $message);
+        $this->assertStringNotContainsString($needle, $display, $message);
     }
 
     /**
@@ -121,7 +119,7 @@ protected function assertDisplayRegExp($command, $pattern, $message = '')
     {
         $display = $this->getMagerunTester($command)->getDisplay();
 
-        self::assertMatchesRegularExpression($pattern, $display, $message);
+        $this->assertMatchesRegularExpression($pattern, $display, $message);
     }
 
     /**
@@ -133,17 +131,17 @@ protected function assertDisplayRegExp($command, $pattern, $message = '')
      */
     protected function assertExecute($command, $message = '')
     {
-        $tester = $this->getMagerunTester($command);
-        $status = $tester->getStatus();
+        $magerunCommandTester = $this->getMagerunTester($command);
+        $status = $magerunCommandTester->getStatus();
 
-        if (strlen($message)) {
+        if (strlen($message) !== 0) {
             $message .= "\n";
         }
 
         $message .= 'Command executes with a status code of zero';
 
-        self::assertSame(0, $status, $message);
+        $this->assertSame(0, $status, $message);
 
-        return $tester;
+        return $magerunCommandTester;
     }
 }
diff --git a/tests/N98/Magento/DbSettingsTest.php b/tests/N98/Magento/DbSettingsTest.php
index 550f3b4d1..4c990157f 100644
--- a/tests/N98/Magento/DbSettingsTest.php
+++ b/tests/N98/Magento/DbSettingsTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 /**
  * this file is part of magerun
  *
@@ -18,56 +20,47 @@
  *
  * @package N98\Magento
  */
-class DbSettingsTest extends TestCase
+final class DbSettingsTest extends TestCase
 {
-    /**
-     * @test
-     */
-    public function creation()
+    public function testCreation()
     {
         $file = $this->getTestMagentoRoot() . '/app/etc/local.xml';
-        $settings = new DbSettings($file);
-        self::assertInstanceOf(__NAMESPACE__ . '\\DbSettings', $settings);
+        $dbSettings = new DbSettings($file);
+        $this->assertInstanceOf(__NAMESPACE__ . '\\DbSettings', $dbSettings);
     }
 
-    /**
-     * @test
-     */
-    public function settings()
+    public function testSettings()
     {
         $file = __DIR__ . '/local.xml';
 
-        $settings = new DbSettings($file);
+        $dbSettings = new DbSettings($file);
 
-        self::assertSame('', $settings->getTablePrefix());
+        $this->assertSame('', $dbSettings->getTablePrefix());
 
-        self::assertSame('localhost', $settings->getHost());
-        self::assertNull($settings->getPort());
+        $this->assertSame('localhost', $dbSettings->getHost());
+        $this->assertNull($dbSettings->getPort());
 
-        self::assertNull($settings->getUnixSocket());
+        $this->assertNull($dbSettings->getUnixSocket());
 
-        self::assertSame('user', $settings->getUsername());
-        self::assertSame('pass', $settings->getPassword());
+        $this->assertSame('user', $dbSettings->getUsername());
+        $this->assertSame('pass', $dbSettings->getPassword());
 
         // DbSettings is more strict here, only using known DSN settings, see @link http://php.net/ref.pdo-mysql.connection
         // minus those settings that are black-listed: dbname, charset
         // "mysql:host=localhost;initStatements=SET NAMES utf8;model=mysql4;type=pdo_mysql;pdoType=;active=1;prefix="
-        self::assertEquals('mysql:host=localhost', $settings->getDsn());
+        $this->assertSame('mysql:host=localhost', $dbSettings->getDsn());
     }
 
-    /**
-     * @test
-     */
-    public function arrayAccess()
+    public function testArrayAccess()
     {
         $file = __DIR__ . '/local.xml';
-        $settings = new DbSettings($file);
+        $dbSettings = new DbSettings($file);
 
-        self::assertSame('user', $settings['username']);
-        self::assertSame('pass', $settings['password']);
+        $this->assertSame('user', $dbSettings['username']);
+        $this->assertSame('pass', $dbSettings['password']);
 
         // unix_socket should be NULL
-        self::assertNull($settings['unix_socket']);
+        $this->assertNull($dbSettings['unix_socket']);
 
         // it's still leaky:
         // self::assertInstanceOf(SimpleXMLElement::class, $settings['pdoType']);
diff --git a/tests/N98/Magento/MagerunCommandTester.php b/tests/N98/Magento/MagerunCommandTester.php
index 2a0582bf4..4717d3065 100644
--- a/tests/N98/Magento/MagerunCommandTester.php
+++ b/tests/N98/Magento/MagerunCommandTester.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Magento;
 
 use InvalidArgumentException;
@@ -42,7 +44,6 @@ class MagerunCommandTester
     /**
      * MagerunCommandTester constructor.
      *
-     * @param TestCase $testCase
      * @param string|array $input
      */
     public function __construct(TestCase $testCase, array $input)
@@ -51,6 +52,7 @@ public function __construct(TestCase $testCase, array $input)
 
         $testCase->assertArrayHasKey('command', $input);
         $testCase->assertIsString($input['command']);
+
         $this->commandName = $input['command'];
         $this->input = $input;
     }
@@ -86,7 +88,7 @@ public function getStatus()
     private function getExecutedCommandTester()
     {
         $commandTester = $this->getCommandTester();
-        if (!isset($this->status)) {
+        if ($this->status === null) {
             $this->status = $commandTester->execute($this->input);
         }
 
@@ -99,7 +101,7 @@ private function getExecutedCommandTester()
     private function getCommandTester()
     {
         $command = null;
-        if (isset($this->commandTester)) {
+        if ($this->commandTester !== null) {
             return $this->commandTester;
         }
 
diff --git a/tests/N98/Magento/ModulesTest.php b/tests/N98/Magento/ModulesTest.php
index 17b2c2492..94b7fb082 100644
--- a/tests/N98/Magento/ModulesTest.php
+++ b/tests/N98/Magento/ModulesTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 /**
  * this file is part of magerun
  *
@@ -19,52 +21,43 @@
  * @package N98\Magento
  * @covers N98\Magento\Modules
  */
-class ModulesTest extends TestCase
+final class ModulesTest extends TestCase
 {
-    /**
-     * @test
-     */
-    public function creation()
+    public function testCreation()
     {
         $modules = new Modules();
-        self::assertInstanceOf(__NAMESPACE__ . '\Modules', $modules);
+        $this->assertInstanceOf(__NAMESPACE__ . '\Modules', $modules);
     }
 
-    /**
-     * @test
-     */
-    public function filteringCountAndIterating()
+    public function testFilteringCountAndIterating()
     {
         $modules = new Modules();
 
         $result = $modules->filterModules(
             $this->filter(),
         );
-        self::assertInstanceOf(__NAMESPACE__ . '\Modules', $result);
-        self::assertCount(0, $result);
-        self::assertCount(0, iterator_to_array($result));
+        $this->assertInstanceOf(__NAMESPACE__ . '\Modules', $result);
+        $this->assertCount(0, $result);
+        $this->assertCount(0, iterator_to_array($result));
     }
 
-    /**
-     * @test
-     */
-    public function findInstalledModulesAndFilterThem()
+    public function testFindInstalledModulesAndFilterThem()
     {
         $this->getApplication()->initMagento();
 
         $modules = new Modules();
-        self::assertCount(0, $modules);
+        $this->assertCount(0, $modules);
         $total = count($modules->findInstalledModules());
-        self::assertGreaterThan(10, $total);
+        $this->assertGreaterThan(10, $total);
 
         $filtered = $modules->filterModules($this->filter('codepool', 'core'));
-        self::assertLessThan($total, count($filtered));
+        $this->assertLessThan($total, count($filtered));
 
         $filtered = $modules->filterModules($this->filter('status', 'active'));
-        self::assertLessThan($total, count($filtered));
+        $this->assertLessThan($total, count($filtered));
 
         $filtered = $modules->filterModules($this->filter('vendor', 'Mage_'));
-        self::assertLessThan($total, count($filtered));
+        $this->assertLessThan($total, count($filtered));
     }
 
     /**
@@ -83,6 +76,7 @@ private function filter($option = null, $value = null)
             if (!array_key_exists($option, $defaultOptions)) {
                 throw new InvalidArgumentException(sprintf('Invalid option "%s"', $option));
             }
+
             $options[$option] = $value;
         }
 
diff --git a/tests/N98/Magento/TestApplication.php b/tests/N98/Magento/TestApplication.php
index 3f4caa2ee..07bd40cb1 100644
--- a/tests/N98/Magento/TestApplication.php
+++ b/tests/N98/Magento/TestApplication.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 /*
  * this file is part of magerun
  *
@@ -61,8 +63,9 @@ public static function getTestMagentoRootFromEnvironment($varname, $basename)
                 $root = $buffer;
             }
         }
+
         if (empty($root)) {
-            return;
+            return null;
         }
 
         # directory test
@@ -84,7 +87,6 @@ public static function getTestMagentoRootFromEnvironment($varname, $basename)
     }
 
     /**
-     * @param TestCase $testCase
      * @return array
      */
     public static function getConfig(TestCase $testCase)
@@ -97,7 +99,6 @@ public static function getConfig(TestCase $testCase)
     /**
      * TestApplication constructor.
      *
-     * @param TestCase $testCase
      * @param null $varname [optional] name of the environment variable containing the path to magento-root, "N98_MAGERUN_TEST_MAGENTO_ROOT" by default
      * @param null $basename [optional] of the stop-file, ".n98-magerun" by default
      */
@@ -106,9 +107,11 @@ public function __construct(TestCase $testCase, $varname = null, $basename = nul
         if (null === $varname) {
             $varname = 'N98_MAGERUN_TEST_MAGENTO_ROOT';
         }
+
         if (null === $basename) {
             $basename = '.n98-magerun';
         }
+
         $this->testCase = $testCase;
         $this->varname = $varname;
         $this->basename = $basename;
@@ -133,7 +136,7 @@ public function getTestMagentoRoot()
 
         if (null === $root) {
             throw new SkippedTestError(
-                "Please specify environment variable $varname with path to your test magento installation!",
+                sprintf('Please specify environment variable %s with path to your test magento installation!', $varname),
             );
         }
 
diff --git a/tests/N98/Magento/TestApplicationTest.php b/tests/N98/Magento/TestApplicationTest.php
index 36943812d..5a7f89795 100644
--- a/tests/N98/Magento/TestApplicationTest.php
+++ b/tests/N98/Magento/TestApplicationTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 /*
  * this file is part of magerun
  *
@@ -10,36 +12,27 @@
 
 use PHPUnit\Framework\TestCase;
 
-class TestApplicationTest extends TestCase
+final class TestApplicationTest extends TestCase
 {
-    /**
-     * @test
-     */
-    public function creation()
+    public function testCreation()
     {
-        $application = new TestApplication($this);
-        self::assertInstanceOf(__NAMESPACE__ . '\TestApplication', $application);
+        $testApplication = new TestApplication($this);
+        $this->assertInstanceOf(__NAMESPACE__ . '\TestApplication', $testApplication);
     }
 
-    /**
-     * @test
-     */
-    public function magentoTestRoot()
+    public function testMagentoTestRoot()
     {
-        $application = new TestApplication($this);
-        $actual = $application->getTestMagentoRoot();
-        self::assertIsString($actual);
-        self::assertGreaterThan(10, strlen($actual));
-        self::assertDirectoryExists($actual);
+        $testApplication = new TestApplication($this);
+        $actual = $testApplication->getTestMagentoRoot();
+        $this->assertIsString($actual);
+        $this->assertGreaterThan(10, strlen($actual));
+        $this->assertDirectoryExists($actual);
     }
 
-    /**
-     * @test
-     */
-    public function getApplication()
+    public function testGetApplication()
     {
-        $application = new TestApplication($this);
-        $actual = $application->getApplication();
-        self::assertInstanceOf(__NAMESPACE__ . '\Application', $actual);
+        $testApplication = new TestApplication($this);
+        $actual = $testApplication->getApplication();
+        $this->assertInstanceOf(__NAMESPACE__ . '\Application', $actual);
     }
 }
diff --git a/tests/N98/Magento/_ApplicationTestComposer/FooCommand.php b/tests/N98/Magento/_ApplicationTestComposer/FooCommand.php
index d75e794ba..32243ea19 100644
--- a/tests/N98/Magento/_ApplicationTestComposer/FooCommand.php
+++ b/tests/N98/Magento/_ApplicationTestComposer/FooCommand.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Acme;
 
 use N98\Magento\Command\AbstractMagentoCommand;
diff --git a/tests/N98/Magento/_ApplicationTestModules/test_dummy_module/src/TestModule/FooCommand.php b/tests/N98/Magento/_ApplicationTestModules/test_dummy_module/src/TestModule/FooCommand.php
index 46b7d5b47..b02e5fb8f 100644
--- a/tests/N98/Magento/_ApplicationTestModules/test_dummy_module/src/TestModule/FooCommand.php
+++ b/tests/N98/Magento/_ApplicationTestModules/test_dummy_module/src/TestModule/FooCommand.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace TestModule;
 
 use N98\Magento\Command\AbstractMagentoCommand;
@@ -16,8 +18,6 @@ protected function configure()
     }
 
     /**
-     * @param InputInterface $input
-     * @param OutputInterface $output
      * @return int|void
      */
     protected function execute(InputInterface $input, OutputInterface $output): int
@@ -26,6 +26,7 @@ protected function execute(InputInterface $input, OutputInterface $output): int
         if (!$this->initMagento()) {
             return 0;
         }
+
         return 0;
     }
 }
diff --git a/tests/N98/Magento/_ApplicationTestSrc/N98MagerunTest/AlternativeConfigModel.php b/tests/N98/Magento/_ApplicationTestSrc/N98MagerunTest/AlternativeConfigModel.php
index c3044efba..f86e20360 100644
--- a/tests/N98/Magento/_ApplicationTestSrc/N98MagerunTest/AlternativeConfigModel.php
+++ b/tests/N98/Magento/_ApplicationTestSrc/N98MagerunTest/AlternativeConfigModel.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98MagerunTest;
 
 use Mage_Core_Model_Config;
diff --git a/tests/N98/Magento/_ApplicationTestSrc/N98MagerunTest/TestDummyCommand.php b/tests/N98/Magento/_ApplicationTestSrc/N98MagerunTest/TestDummyCommand.php
index 2c63eb50a..35e0a051f 100644
--- a/tests/N98/Magento/_ApplicationTestSrc/N98MagerunTest/TestDummyCommand.php
+++ b/tests/N98/Magento/_ApplicationTestSrc/N98MagerunTest/TestDummyCommand.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98MagerunTest;
 
 use N98\Magento\Command\AbstractMagentoCommand;
diff --git a/tests/N98/Util/ArrayFunctionsTest.php b/tests/N98/Util/ArrayFunctionsTest.php
index e8f4804d6..8ae2ba84b 100644
--- a/tests/N98/Util/ArrayFunctionsTest.php
+++ b/tests/N98/Util/ArrayFunctionsTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Util;
 
 use PHPUnit\Framework\TestCase;
@@ -9,100 +11,96 @@
  *
  * @covers N98\Util\ArrayFunctions
  */
-class ArrayFunctionsTest extends TestCase
+final class ArrayFunctionsTest extends TestCase
 {
     /**
-     * @test
      * @dataProvider mergeArraysProvider
      */
-    public function mergeArrays(array $a, array $b, array $expected)
+    public function testMergeArrays(array $a, array $b, array $expected)
     {
-        self::assertEquals($expected, ArrayFunctions::mergeArrays($a, $b));
+        $this->assertEquals($expected, ArrayFunctions::mergeArrays($a, $b));
     }
 
     /**
-     * @return array
+     * @return \Iterator<(int | string), mixed>
      */
-    public function mergeArraysProvider()
+    public function mergeArraysProvider(): \Iterator
     {
-        return [
-            [[], ['Foo', 'Bar'], ['Foo', 'Bar']],
-            [['Foo', 'Bar'], [], ['Foo', 'Bar']],
-            [['Foo'], ['Bar'], ['Foo', 'Bar']],
-            [['Foo', ['Bar']], ['Bar'], ['Foo', ['Bar'], 'Bar']],
-            /**
-             * Override Bar->Bar
-             */
-            [['Foo', 'Bar' => ['Bar' => 1]], ['Bar' => ['Bar' => 2]], ['Foo', 'Bar' => ['Bar' => 2]]],
-        ];
+        yield [[], ['Foo', 'Bar'], ['Foo', 'Bar']];
+        yield [['Foo', 'Bar'], [], ['Foo', 'Bar']];
+        yield [['Foo'], ['Bar'], ['Foo', 'Bar']];
+        yield [['Foo', ['Bar']], ['Bar'], ['Foo', ['Bar'], 'Bar']];
+        /**
+         * Override Bar->Bar
+         */
+        yield [['Foo', 'Bar' => ['Bar' => 1]], ['Bar' => ['Bar' => 2]], ['Foo', 'Bar' => ['Bar' => 2]]];
     }
 
-    /**
-     * @test
-     */
-    public function columnOrderArrayTable()
+    public function testColumnOrderArrayTable()
     {
         $headers = ['foo', 'bar', 'baz'];
         $table = [['foo' => 'A1', 'baz' => 'C1', 'B1', 'D1'], ['A2', 'B2', 'C2', 'D2'], [null, null, null, 'foo' => 'A3']];
 
         $actual = ArrayFunctions::columnOrderArrayTable($headers, $table);
-        self::assertIsArray($actual);
-        self::assertCount(count($table), $actual);
+        $this->assertIsArray($actual);
+        $this->assertCount(count($table), $actual);
         $expected = [['foo' => 'A1', 'bar' => 'B1', 'baz' => 'C1', 'D1'], ['foo' => 'A2', 'bar' => 'B2', 'baz' => 'C2', 'D2'], ['foo' => 'A3', 'bar' => null, 'baz' => null, null]];
-        self::assertEquals($expected, $actual);
-        self::assertSame($expected, $actual);
+        $this->assertEquals($expected, $actual);
+        $this->assertSame($expected, $actual);
     }
 
     /**
-     * @test
      * @dataProvider provideColumnOrderings
      */
-    public function columnOrder($columns, $array, $expected)
+    public function testColumnOrder($columns, $array, $expected)
     {
         $actual = ArrayFunctions::columnOrder($columns, $array);
-        self::assertIsArray($actual);
-        self::assertEquals($expected, $actual);
-        self::assertSame($expected, $actual);
+        $this->assertIsArray($actual);
+        $this->assertEquals($expected, $actual);
+        $this->assertSame($expected, $actual);
     }
 
     /**
      * @see columnOrder
-     * @return array
+     * @return \Iterator<(int | string), mixed>
      */
-    public function provideColumnOrderings()
+    public function provideColumnOrderings(): \Iterator
     {
-        return [[['foo', 'bar', 'baz'], ['A', 'B', 'C'], ['foo' => 'A', 'bar' => 'B', 'baz' => 'C']], [['foo', 'bar', 'baz'], ['A', 'B', 'C', 'D'], ['foo' => 'A', 'bar' => 'B', 'baz' => 'C', 'D']], [['foo', 'bar', 'baz'], ['A', 'B', 'C'], ['foo' => 'A', 'bar' => 'B', 'baz' => 'C']], [['foo', 'bar', 'baz'], ['buz' => 'D', 'A', 'B', 'C'], ['foo' => 'A', 'bar' => 'B', 'baz' => 'C', 'buz' => 'D']], [['foo', 'bar', 'baz'], ['foo' => 'A', 'baz' => 'C', 'B', 'D'], ['foo' => 'A', 'bar' => 'B', 'baz' => 'C', 'D']], [['foo', 'bar', 'baz'], ['foo' => 'A', 'baz' => 'C'], ['foo' => 'A', 'bar' => null, 'baz' => 'C']]];
+        yield [['foo', 'bar', 'baz'], ['A', 'B', 'C'], ['foo' => 'A', 'bar' => 'B', 'baz' => 'C']];
+        yield [['foo', 'bar', 'baz'], ['A', 'B', 'C', 'D'], ['foo' => 'A', 'bar' => 'B', 'baz' => 'C', 'D']];
+        yield [['foo', 'bar', 'baz'], ['A', 'B', 'C'], ['foo' => 'A', 'bar' => 'B', 'baz' => 'C']];
+        yield [['foo', 'bar', 'baz'], ['buz' => 'D', 'A', 'B', 'C'], ['foo' => 'A', 'bar' => 'B', 'baz' => 'C', 'buz' => 'D']];
+        yield [['foo', 'bar', 'baz'], ['foo' => 'A', 'baz' => 'C', 'B', 'D'], ['foo' => 'A', 'bar' => 'B', 'baz' => 'C', 'D']];
+        yield [['foo', 'bar', 'baz'], ['foo' => 'A', 'baz' => 'C'], ['foo' => 'A', 'bar' => null, 'baz' => 'C']];
     }
 
     /**
      * @see matrixFilterByValue
      * @see matrixFilterStartsWith
-     * @return array
+     * @return \Iterator<(int | string), mixed>
      */
-    public function provideMatrix()
+    public function provideMatrix(): \Iterator
     {
-        return [[[['foo' => 'bar'], ['foo' => 'baz'], ['foo' => 'zaz']]]];
+        yield [[['foo' => 'bar'], ['foo' => 'baz'], ['foo' => 'zaz']]];
     }
 
     /**
-     * @test
      * @dataProvider provideMatrix
      */
-    public function matrixFilterByValue(array $matrix)
+    public function testMatrixFilterByValue(array $matrix)
     {
-        self::assertCount(3, $matrix);
+        $this->assertCount(3, $matrix);
         $filtered = ArrayFunctions::matrixFilterByValue($matrix, 'foo', 'bar');
-        self::assertCount(1, $filtered);
+        $this->assertCount(1, $filtered);
     }
 
     /**
-     * @test
      * @dataProvider provideMatrix
      */
-    public function matrixFilterStartsWith(array $matrix)
+    public function testMatrixFilterStartsWith(array $matrix)
     {
-        self::assertCount(3, $matrix);
+        $this->assertCount(3, $matrix);
         $filtered = ArrayFunctions::matrixFilterStartswith($matrix, 'foo', 'ba');
-        self::assertCount(2, $filtered);
+        $this->assertCount(2, $filtered);
     }
 }
diff --git a/tests/N98/Util/AutoloadHandlerTest.php b/tests/N98/Util/AutoloadHandlerTest.php
index 39d1c2765..591852e0d 100644
--- a/tests/N98/Util/AutoloadHandlerTest.php
+++ b/tests/N98/Util/AutoloadHandlerTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 /**
  * this file is part of magerun
  *
@@ -17,7 +19,7 @@
  * @covers \N98\Util\AutoloadHandler
  * @package N98\Util
  */
-class AutoloadHandlerTest extends TestCase
+final class AutoloadHandlerTest extends TestCase
 {
     private array $cleanup = [];
 
@@ -31,20 +33,14 @@ protected function tearDown(): void
         parent::tearDown();
     }
 
-    /**
-     * @test
-     */
-    public function creation()
+    public function testCreation()
     {
         $handler = $this->create(null);
-        self::assertInstanceOf(__NAMESPACE__ . '\AutoloadHandler', $handler);
-        self::assertIsCallable($handler);
+        $this->assertInstanceOf(__NAMESPACE__ . '\AutoloadHandler', $handler);
+        $this->assertIsCallable($handler);
     }
 
-    /**
-     * @test
-     */
-    public function noRegistrationOnCreation(): never
+    public function testNoRegistrationOnCreation(): never
     {
         $this->expectException(BadMethodCallException::class);
         $this->expectExceptionMessage('Autoload callback is not callable');
@@ -52,11 +48,11 @@ public function noRegistrationOnCreation(): never
         $handler = $this->create(null, AutoloadHandler::NO_AUTO_REGISTER);
         $handler->disable(); // assertions require a disabled handler b/c of exceptions
 
-        self::assertNotContains($handler, spl_autoload_functions());
-        self::assertFalse($handler->__invoke('test'));
+        $this->assertNotContains($handler, spl_autoload_functions());
+        $this->assertFalse($handler->__invoke('test'));
         $handler->register();
         $actual = in_array($handler, spl_autoload_functions());
-        self::assertTrue($actual);
+        $this->assertTrue($actual);
 
         $handler->enable();
         $handler->__invoke('test');
@@ -71,10 +67,7 @@ private function create($implementation, $flags = null)
         return $autoloadHandler;
     }
 
-    /**
-     * @test
-     */
-    public function registrationAndDeregistration()
+    public function testRegistrationAndDeregistration()
     {
         $calls = (object) ['retval' => true];
         $assertAble = function ($className) use (&$calls) {
@@ -85,18 +78,15 @@ public function registrationAndDeregistration()
         };
 
         $handler = $this->create($assertAble);
-        self::assertTrue($handler->isEnabled());
-        self::assertTrue($handler->__invoke('Fake'));
+        $this->assertTrue($handler->isEnabled());
+        $this->assertTrue($handler->__invoke('Fake'));
 
         $handler->unregister();
-        self::assertFalse($handler->__invoke('Fake'));
-        self::assertEquals(1, $calls->count['Fake']);
+        $this->assertFalse($handler->__invoke('Fake'));
+        $this->assertSame(1, $calls->count['Fake']);
     }
 
-    /**
-     * @test
-     */
-    public function changingCallback()
+    public function testChangingCallback()
     {
         $calls = (object) ['retval' => true];
         $assertAble = function ($className) use (&$calls) {
@@ -107,55 +97,46 @@ public function changingCallback()
         };
 
         $handler = $this->create(null, AutoloadHandler::NO_EXCEPTION);
-        self::assertFalse($handler->__invoke('Test'));
-        self::assertObjectNotHasProperty('count', $calls);
+        $this->assertFalse($handler->__invoke('Test'));
+        $this->assertObjectNotHasProperty('count', $calls);
 
         $handler->setCallback($assertAble);
-        self::assertTrue($handler->__invoke('Test'));
-        self::assertEquals(1, $calls->count['Test']);
+        $this->assertTrue($handler->__invoke('Test'));
+        $this->assertSame(1, $calls->count['Test']);
 
         $handler->setCallback(null);
-        self::assertFalse($handler->__invoke('Test'));
-        self::assertEquals(1, $calls->count['Test']);
+        $this->assertFalse($handler->__invoke('Test'));
+        $this->assertSame(1, $calls->count['Test']);
     }
 
-    /**
-     * @test
-     */
-    public function disablingAndEnabling(): never
+    public function testDisablingAndEnabling(): never
     {
         $handler = $this->create(null);
         $handler->setEnabled(false);
-        self::assertFalse($handler->__invoke('Test'));
+        $this->assertFalse($handler->__invoke('Test'));
         $handler->setEnabled(true);
         $this->expectException(BadMethodCallException::class);
-        self::assertFalse($handler->__invoke('Test'));
+        $this->assertFalse($handler->__invoke('Test'));
         self::fail('An expected exception has not been thrown');
     }
 
-    /**
-     * @test
-     */
-    public function callbackSelfReference()
+    public function testCallbackSelfReference()
     {
         $testClass = 'MyOf' . random_int(1000, 9999) . 'Fake' . random_int(1000, 9999) . 'Class';
         $test = $this;
-        $handler = $this->create(function ($className) use (&$handler, $test, $testClass) {
+        $handler = $this->create(function ($className) use (&$handler, $test, $testClass): void {
             /** @var $handler AutoloadHandler */
-            $test->assertEquals($testClass, $className);
+            $test->assertSame($testClass, $className);
             $handler->disable();
         });
         $actual = class_exists($testClass);
         $isEnabled = $handler->isEnabled();
-        self::assertEquals(1, self::getCount());
-        self::assertFalse($isEnabled);
-        self::assertFalse($actual);
+        $this->assertSame(1, self::getCount());
+        $this->assertFalse($isEnabled);
+        $this->assertFalse($actual);
     }
 
-    /**
-     * @test
-     */
-    public function cleanupCallback()
+    public function testCleanupCallback()
     {
         $calls = (object) ['retval' => true];
         $assertAble = function ($className) use (&$calls) {
@@ -168,10 +149,10 @@ public function cleanupCallback()
         $handler = $this->create($assertAble, AutoloadHandler::NO_EXCEPTION);
         $cleanup = $handler->getCleanupCallback();
         $actual = class_exists('Test');
-        self::assertFalse($actual);
-        self::assertContains($handler, spl_autoload_functions(), 'before cleanup');
+        $this->assertFalse($actual);
+        $this->assertContains($handler, spl_autoload_functions(), 'before cleanup');
         $cleanup();
-        self::assertNotContains($handler, spl_autoload_functions(), 'after cleanup');
+        $this->assertNotContains($handler, spl_autoload_functions(), 'after cleanup');
         // calling cleanup again must not do any warnings etc.
         $cleanup();
     }
diff --git a/tests/N98/Util/AutoloadRestorerTest.php b/tests/N98/Util/AutoloadRestorerTest.php
index d27140f0c..3227f866f 100644
--- a/tests/N98/Util/AutoloadRestorerTest.php
+++ b/tests/N98/Util/AutoloadRestorerTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 /**
  * this file is part of magerun
  *
@@ -15,37 +17,31 @@
  *
  * @package N98\Util
  */
-class AutoloadRestorerTest extends TestCase
+final class AutoloadRestorerTest extends TestCase
 {
-    /**
-     * @test
-     */
-    public function creation()
+    public function testCreation()
     {
         $autoloadRestorer = new AutoloadRestorer();
 
-        self::assertInstanceOf(AutoloadRestorer::class, $autoloadRestorer);
+        $this->assertInstanceOf(AutoloadRestorer::class, $autoloadRestorer);
     }
 
-    /**
-     * @test
-     */
-    public function restoration()
+    public function testRestoration()
     {
-        $callbackStub = function () {};
+        $callbackStub = function (): void {};
 
-        self::assertTrue(spl_autoload_register($callbackStub));
+        $this->assertTrue(spl_autoload_register($callbackStub));
 
         $autoloadRestorer = new AutoloadRestorer();
 
-        self::assertContains($callbackStub, spl_autoload_functions());
+        $this->assertContains($callbackStub, spl_autoload_functions());
 
-        self::assertTrue(spl_autoload_unregister($callbackStub));
+        $this->assertTrue(spl_autoload_unregister($callbackStub));
 
-        self::assertNotContains($callbackStub, spl_autoload_functions());
+        $this->assertNotContains($callbackStub, spl_autoload_functions());
 
         $autoloadRestorer->restore();
 
-        self::assertContains($callbackStub, spl_autoload_functions());
+        $this->assertContains($callbackStub, spl_autoload_functions());
     }
 }
diff --git a/tests/N98/Util/BinaryStringTest.php b/tests/N98/Util/BinaryStringTest.php
index 24dc4d8f9..abf54e964 100644
--- a/tests/N98/Util/BinaryStringTest.php
+++ b/tests/N98/Util/BinaryStringTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Util;
 
 use PHPUnit\Framework\TestCase;
@@ -9,25 +11,26 @@
  *
  * @covers \N98\Util\BinaryString
  */
-class BinaryStringTest extends TestCase
+final class BinaryStringTest extends TestCase
 {
     /**
-     * @test
      * @param string $string
      * @param string $delimiter
      * @param array  $expected
      * @dataProvider trimExplodeEmptyProvider
      */
-    public function trimExplodeEmpty($delimiter, $string, $expected)
+    public function testTrimExplodeEmpty($delimiter, $string, $expected)
     {
-        self::assertEqualsCanonicalizing($expected, BinaryString::trimExplodeEmpty($delimiter, $string));
+        $this->assertEqualsCanonicalizing($expected, BinaryString::trimExplodeEmpty($delimiter, $string));
     }
 
     /**
-     * @return array
+     * @return \Iterator<(int | string), mixed>
      */
-    public function trimExplodeEmptyProvider()
+    public function trimExplodeEmptyProvider(): \Iterator
     {
-        return [[',', 'Foo,Bar', ['Foo', 'Bar']], ['#', ' Foo# Bar', ['Foo', 'Bar']], [',', ',,Foo, Bar,,', ['Foo', 'Bar']]];
+        yield [',', 'Foo,Bar', ['Foo', 'Bar']];
+        yield ['#', ' Foo# Bar', ['Foo', 'Bar']];
+        yield [',', ',,Foo, Bar,,', ['Foo', 'Bar']];
     }
 }
diff --git a/tests/N98/Util/Console/Helper/DatabaseHelperTest.php b/tests/N98/Util/Console/Helper/DatabaseHelperTest.php
index 27855700a..bba9623e9 100644
--- a/tests/N98/Util/Console/Helper/DatabaseHelperTest.php
+++ b/tests/N98/Util/Console/Helper/DatabaseHelperTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Util\Console\Helper;
 
 use PDO;
@@ -13,7 +15,7 @@
  *
  * @covers  \N98\Util\Console\Helper\DatabaseHelper
  */
-class DatabaseHelperTest extends TestCase
+final class DatabaseHelperTest extends TestCase
 {
     /**
      * @var array of functions to call on teardown
@@ -24,7 +26,7 @@ class DatabaseHelperTest extends TestCase
     /**
      * @return DatabaseHelper
      */
-    protected function getHelper()
+    private function getHelper()
     {
         $command = $this->getApplication()->find('db:info');
         $command->getHelperSet()->setCommand($command);
@@ -34,56 +36,44 @@ protected function getHelper()
 
     public function testHelperInstance()
     {
-        self::assertInstanceOf(DatabaseHelper::class, $this->getHelper());
+        $this->assertInstanceOf(DatabaseHelper::class, $this->getHelper());
     }
 
-    /**
-     * @test
-     */
-    public function getConnection()
+    public function testGetConnection()
     {
-        self::assertInstanceOf(PDO::class, $this->getHelper()->getConnection());
+        $this->assertInstanceOf(PDO::class, $this->getHelper()->getConnection());
     }
 
-    /**
-     * @test
-     */
-    public function dsn()
+    public function testDsn()
     {
-        self::assertStringStartsWith('mysql:', $this->getHelper()->dsn());
+        $this->assertStringStartsWith('mysql:', $this->getHelper()->dsn());
     }
 
-    /**
-     * @test
-     */
-    public function mysqlUserHasPrivilege()
+    public function testMysqlUserHasPrivilege()
     {
-        self::assertTrue($this->getHelper()->mysqlUserHasPrivilege('SELECT'));
+        $this->assertTrue($this->getHelper()->mysqlUserHasPrivilege('SELECT'));
     }
 
-    /**
-     * @test
-     */
-    public function getMysqlVariableValue()
+    public function testGetMysqlVariableValue()
     {
-        $helper = $this->getHelper();
+        $databaseHelper = $this->getHelper();
 
         // verify (complex) return value with existing global variable
-        $actual = $helper->getMysqlVariableValue('version');
+        $actual = $databaseHelper->getMysqlVariableValue('version');
 
-        self::assertIsArray($actual);
-        self::assertCount(1, $actual);
+        $this->assertIsArray($actual);
+        $this->assertCount(1, $actual);
         $key = '@@version';
-        self::assertArrayHasKey($key, $actual);
-        self::assertIsString($actual[$key]);
+        $this->assertArrayHasKey($key, $actual);
+        $this->assertIsString($actual[$key]);
 
         // quoted
-        $actual = $helper->getMysqlVariableValue('`version`');
-        self::assertEquals('@@`version`', key($actual));
+        $actual = $databaseHelper->getMysqlVariableValue('`version`');
+        $this->assertSame('@@`version`', key($actual));
 
         // non-existent global variable
         try {
-            $helper->getMysqlVariableValue('nonexistent');
+            $databaseHelper->getMysqlVariableValue('nonexistent');
             self::fail('An expected exception has not been thrown');
         } catch (RuntimeException $runtimeException) {
             // do nothing -> We need to check different strings for old MySQL and MariaDB servers
@@ -91,25 +81,22 @@ public function getMysqlVariableValue()
         }
     }
 
-    /**
-     * @test
-     */
-    public function getMysqlVariable()
+    public function testGetMysqlVariable()
     {
-        $helper = $this->getHelper();
+        $databaseHelper = $this->getHelper();
 
         // behaviour with existing global variable
-        $actual = $helper->getMysqlVariable('version');
-        self::assertIsString($actual);
+        $actual = $databaseHelper->getMysqlVariable('version');
+        $this->assertIsString($actual);
 
         // behavior with existent session variable (INTEGER)
-        $helper->getConnection()->query('SET @existent = 14;');
-        $actual = $helper->getMysqlVariable('existent', '@');
-        self::assertEquals(14, $actual);
+        $databaseHelper->getConnection()->query('SET @existent = 14;');
+        $actual = $databaseHelper->getMysqlVariable('existent', '@');
+        $this->assertSame(14, $actual);
 
         // behavior with non-existent session variable
-        $actual = $helper->getMysqlVariable('nonexistent', '@');
-        self::assertNull($actual);
+        $actual = $databaseHelper->getMysqlVariable('nonexistent', '@');
+        $this->assertNull($actual);
 
         // behavior with non-existent global variable
         /*
@@ -127,29 +114,23 @@ public function getMysqlVariable()
 
         // invalid variable type
         try {
-            $helper->getMysqlVariable('nonexistent', '@@@');
+            $databaseHelper->getMysqlVariable('nonexistent', '@@@');
             self::fail('An expected Exception has not been thrown');
         } catch (InvalidArgumentException $invalidArgumentException) {
             // test against the mysql error message
-            self::assertEquals(
-                'Invalid mysql variable type "@@@", must be "@@" (system) or "@" (session)',
-                $invalidArgumentException->getMessage(),
-            );
+            $this->assertSame('Invalid mysql variable type "@@@", must be "@@" (system) or "@" (session)', $invalidArgumentException->getMessage());
         }
     }
 
-    /**
-     * @test
-     */
-    public function getTables()
+    public function testGetTables()
     {
-        $helper = $this->getHelper();
+        $databaseHelper = $this->getHelper();
 
-        $tables = $helper->getTables();
-        self::assertIsArray($tables);
-        self::assertContains('admin_user', $tables);
+        $tables = $databaseHelper->getTables();
+        $this->assertIsArray($tables);
+        $this->assertContains('admin_user', $tables);
 
-        $dbSettings = $helper->getDbSettings();
+        $dbSettings = $databaseHelper->getDbSettings();
         $reflectionObject = new ReflectionObject($dbSettings);
         $reflectionProperty = $reflectionObject->getProperty('config');
         $reflectionProperty->setAccessible(true);
@@ -157,7 +138,7 @@ public function getTables()
         $config = $reflectionProperty->getValue($dbSettings);
         $previous = $config['prefix'];
 
-        $this->tearDownRestore[] = function () use ($reflectionProperty, $dbSettings, $previous) {
+        $this->tearDownRestore[] = function () use ($reflectionProperty, $dbSettings, $previous): void {
             $config = [];
             $config['prefix'] = $previous;
             $reflectionProperty->setValue($dbSettings, $config);
@@ -166,27 +147,24 @@ public function getTables()
         $config['prefix'] = $previous . 'core_';
         $reflectionProperty->setValue($dbSettings, $config);
 
-        $tables = $helper->getTables(null); // default value should be null-able and is false
-        self::assertIsArray($tables);
-        self::assertNotContains('admin_user', $tables);
-        self::assertContains('core_store', $tables);
-        self::assertContains('core_website', $tables);
-
-        $tables = $helper->getTables(true);
-        self::assertIsArray($tables);
-        self::assertNotContains('admin_user', $tables);
-        self::assertContains('store', $tables);
-        self::assertContains('website', $tables);
+        $tables = $databaseHelper->getTables(null); // default value should be null-able and is false
+        $this->assertIsArray($tables);
+        $this->assertNotContains('admin_user', $tables);
+        $this->assertContains('core_store', $tables);
+        $this->assertContains('core_website', $tables);
+
+        $tables = $databaseHelper->getTables(true);
+        $this->assertIsArray($tables);
+        $this->assertNotContains('admin_user', $tables);
+        $this->assertContains('store', $tables);
+        $this->assertContains('website', $tables);
     }
 
-    /**
-     * @test
-     */
-    public function resolveTables()
+    public function testResolveTables()
     {
         $tables = $this->getHelper()->resolveTables(['catalog_*']);
-        self::assertContains('catalog_product_entity', $tables);
-        self::assertNotContains('catalogrule', $tables);
+        $this->assertContains('catalog_product_entity', $tables);
+        $this->assertNotContains('catalogrule', $tables);
 
         $definitions = ['wild_1'   => ['tables' => ['catalog_*']], 'wild_2'   => ['tables' => ['core_config_dat?']], 'dataflow' => ['tables' => ['dataflow_batch_import', 'dataflow_batch_export']]];
 
@@ -194,10 +172,10 @@ public function resolveTables()
             ['@wild_1', '@wild_2', '@dataflow'],
             $definitions,
         );
-        self::assertContains('catalog_product_entity', $tables);
-        self::assertContains('core_config_data', $tables);
-        self::assertContains('dataflow_batch_import', $tables);
-        self::assertNotContains('catalogrule', $tables);
+        $this->assertContains('catalog_product_entity', $tables);
+        $this->assertContains('core_config_data', $tables);
+        $this->assertContains('dataflow_batch_import', $tables);
+        $this->assertNotContains('catalogrule', $tables);
     }
 
     /**
@@ -209,6 +187,7 @@ protected function tearDown(): void
         foreach ($this->tearDownRestore as $singleTearDownRestore) {
             $singleTearDownRestore();
         }
+
         $this->tearDownRestore = null;
 
         parent::tearDown();
diff --git a/tests/N98/Util/Console/Helper/IoHelperTest.php b/tests/N98/Util/Console/Helper/IoHelperTest.php
index 28a79c498..3b20fe118 100644
--- a/tests/N98/Util/Console/Helper/IoHelperTest.php
+++ b/tests/N98/Util/Console/Helper/IoHelperTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 /**
  * this file is part of magerun
  *
@@ -16,18 +18,15 @@
  *
  * @package N98\Util\Console\Helper
  */
-class IoHelperTest extends TestCase
+final class IoHelperTest extends TestCase
 {
-    /**
-     * @test
-     */
-    public function creation()
+    public function testCreation()
     {
         $ioHelper = new IoHelper();
-        self::assertInstanceOf(IoHelper::class, $ioHelper);
-        self::assertInstanceOf(HelperInterface::class, $ioHelper);
-        self::assertNull($ioHelper->getOutput());
+        $this->assertInstanceOf(IoHelper::class, $ioHelper);
+        $this->assertInstanceOf(HelperInterface::class, $ioHelper);
+        $this->assertNull($ioHelper->getOutput());
 
-        self::assertSame('io', $ioHelper->getName());
+        $this->assertSame('io', $ioHelper->getName());
     }
 }
diff --git a/tests/N98/Util/Console/Helper/MagentoHelper.php b/tests/N98/Util/Console/Helper/MagentoHelper.php
index 521a0c320..3c425d072 100644
--- a/tests/N98/Util/Console/Helper/MagentoHelper.php
+++ b/tests/N98/Util/Console/Helper/MagentoHelper.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Util\Console\Helper;
 
 use Symfony\Component\Console\Input\InputInterface;
@@ -26,81 +28,69 @@ public function testHelperInstance()
         self::assertInstanceOf(\N98\Util\Console\Helper\MagentoHelper::class, $this->getHelper());
     }
 
-    /**
-     * @test
-     */
-    public function detectMagentoInStandardFolder()
+    public function testDetectMagentoInStandardFolder()
     {
         vfsStream::setup('root');
         vfsStream::create(
             ['app' => ['Mage.php' => '']],
         );
 
-        $helper = $this->getHelper();
-        $helper->detect(vfsStream::url('root'), []);
+        $magentoHelper = $this->getHelper();
+        $magentoHelper->detect(vfsStream::url('root'), []);
 
-        self::assertEquals(vfsStream::url('root'), $helper->getRootFolder());
+        self::assertSame(vfsStream::url('root'), $magentoHelper->getRootFolder());
     }
 
-    /**
-     * @test
-     */
-    public function detectMagentoInHtdocsSubfolder()
+    public function testDetectMagentoInHtdocsSubfolder()
     {
         vfsStream::setup('root');
         vfsStream::create(
             ['htdocs' => ['app' => ['Mage.php' => '']]],
         );
 
-        $helper = $this->getHelper();
+        $magentoHelper = $this->getHelper();
 
         // vfs cannot resolve relative path so we do 'root/htdocs' etc.
-        $helper->detect(
+        $magentoHelper->detect(
             vfsStream::url('root'),
             [vfsStream::url('root/www'), vfsStream::url('root/public'), vfsStream::url('root/htdocs')],
         );
 
-        self::assertEquals(vfsStream::url('root/htdocs'), $helper->getRootFolder());
+        self::assertSame(vfsStream::url('root/htdocs'), $magentoHelper->getRootFolder());
     }
 
-    /**
-     * @test
-     */
-    public function detectMagentoFailed()
+    public function testDetectMagentoFailed()
     {
         vfsStream::setup('root');
         vfsStream::create(
             ['htdocs' => []],
         );
 
-        $helper = $this->getHelper();
+        $magentoHelper = $this->getHelper();
 
         // vfs cannot resolve relative path so we do 'root/htdocs' etc.
-        $helper->detect(
+        $magentoHelper->detect(
             vfsStream::url('root'),
         );
 
-        self::assertNull($helper->getRootFolder());
+        self::assertNull($magentoHelper->getRootFolder());
     }
 
-    /**
-     * @test
-     */
-    public function detectMagentoInModmanInfrastructure()
+    public function testDetectMagentoInModmanInfrastructure()
     {
         vfsStream::setup('root');
         vfsStream::create(
             ['.basedir' => 'root/htdocs/magento_root', 'htdocs'   => ['magento_root' => ['app' => ['Mage.php' => '']]]],
         );
 
-        $helper = $this->getHelper();
+        $magentoHelper = $this->getHelper();
 
         // vfs cannot resolve relative path so we do 'root/htdocs' etc.
-        $helper->detect(
+        $magentoHelper->detect(
             vfsStream::url('root'),
         );
 
         // Verify if this could be checked with more elegance
-        self::assertEquals(vfsStream::url('root/../root/htdocs/magento_root'), $helper->getRootFolder());
+        self::assertSame(vfsStream::url('root/../root/htdocs/magento_root'), $magentoHelper->getRootFolder());
     }
 }
diff --git a/tests/N98/Util/Console/Helper/Table/Renderer/RenderFactoryTest.php b/tests/N98/Util/Console/Helper/Table/Renderer/RenderFactoryTest.php
index 6c6e17811..1a69abced 100644
--- a/tests/N98/Util/Console/Helper/Table/Renderer/RenderFactoryTest.php
+++ b/tests/N98/Util/Console/Helper/Table/Renderer/RenderFactoryTest.php
@@ -1,10 +1,12 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Util\Console\Helper\Table\Renderer;
 
 use PHPUnit\Framework\TestCase;
 
-class RenderFactoryTest extends TestCase
+final class RenderFactoryTest extends TestCase
 {
     /**
      * @covers \N98\Util\Console\Helper\Table\Renderer\RendererFactory::getFormats
@@ -14,15 +16,15 @@ public function testCreate()
         $rendererFactory = new RendererFactory();
 
         $csv = $rendererFactory->create('csv');
-        self::assertInstanceOf(CsvRenderer::class, $csv);
+        $this->assertInstanceOf(CsvRenderer::class, $csv);
 
         $json = $rendererFactory->create('json');
-        self::assertInstanceOf(JsonRenderer::class, $json);
+        $this->assertInstanceOf(JsonRenderer::class, $json);
 
         $xml = $rendererFactory->create('xml');
-        self::assertInstanceOf(XmlRenderer::class, $xml);
+        $this->assertInstanceOf(XmlRenderer::class, $xml);
 
         $invalidFormat = $rendererFactory->create('invalid_format');
-        self::assertNull($invalidFormat);
+        $this->assertNull($invalidFormat);
     }
 }
diff --git a/tests/N98/Util/Console/Helper/Table/Renderer/TestCase.php b/tests/N98/Util/Console/Helper/Table/Renderer/TestCase.php
index 6b8d18f41..0b1667638 100644
--- a/tests/N98/Util/Console/Helper/Table/Renderer/TestCase.php
+++ b/tests/N98/Util/Console/Helper/Table/Renderer/TestCase.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 /**
  * this file is part of magerun
  *
diff --git a/tests/N98/Util/Console/Helper/Table/Renderer/TextRendererTest.php b/tests/N98/Util/Console/Helper/Table/Renderer/TextRendererTest.php
index 1638ac875..57f2d53fa 100644
--- a/tests/N98/Util/Console/Helper/Table/Renderer/TextRendererTest.php
+++ b/tests/N98/Util/Console/Helper/Table/Renderer/TextRendererTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 /**
  * this file is part of magerun
  *
@@ -17,26 +19,20 @@
  * @covers  N98\Util\Console\Helper\Table\Renderer\TextRenderer
  * @package N98\Util\Console\Helper\Table\Renderer
  */
-class TextRendererTest extends TestCase
+final class TextRendererTest extends TestCase
 {
-    /**
-     * @test
-     */
-    public function creation()
+    public function testCreation()
     {
         $renderer = new TextRenderer();
-        self::assertInstanceOf(__NAMESPACE__ . '\\TextRenderer', $renderer);
+        $this->assertInstanceOf(__NAMESPACE__ . '\\TextRenderer', $renderer);
 
         $rendererFactory = new RendererFactory();
 
         $renderer = $rendererFactory->create('text');
-        self::assertInstanceOf(__NAMESPACE__ . '\\TextRenderer', $renderer);
+        $this->assertInstanceOf(__NAMESPACE__ . '\\TextRenderer', $renderer);
     }
 
-    /**
-     * @test
-     */
-    public function rendering()
+    public function testRendering()
     {
         $textRenderer = new TextRenderer();
         $streamOutput = new StreamOutput(fopen('php://memory', 'wb', false));
@@ -55,6 +51,6 @@ public function rendering()
 
         $textRenderer->render($streamOutput, $rows);
 
-        self::assertEquals($expected, $this->getOutputBuffer($streamOutput));
+        $this->assertSame($expected, $this->getOutputBuffer($streamOutput));
     }
 }
diff --git a/tests/N98/Util/Console/Helper/Table/Renderer/XmlRendererTest.php b/tests/N98/Util/Console/Helper/Table/Renderer/XmlRendererTest.php
index 4d770675d..32aea7ae6 100644
--- a/tests/N98/Util/Console/Helper/Table/Renderer/XmlRendererTest.php
+++ b/tests/N98/Util/Console/Helper/Table/Renderer/XmlRendererTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 /**
  * this file is part of magerun
  *
@@ -20,29 +22,26 @@
  * @covers  N98\Util\Console\Helper\Table\Renderer\XmlRenderer
  * @package N98\Util\Console\Helper\Table\Renderer
  */
-class XmlRendererTest extends TestCase
+final class XmlRendererTest extends TestCase
 {
-    /**
-     * @test
-     */
-    public function creation()
+    public function testCreation()
     {
         $renderer = new XmlRenderer();
-        self::assertInstanceOf(__NAMESPACE__ . '\\XmlRenderer', $renderer);
+        $this->assertInstanceOf(__NAMESPACE__ . '\\XmlRenderer', $renderer);
 
         $rendererFactory = new RendererFactory();
 
         $renderer = $rendererFactory->create('xml');
-        self::assertInstanceOf(__NAMESPACE__ . '\\XmlRenderer', $renderer);
+        $this->assertInstanceOf(__NAMESPACE__ . '\\XmlRenderer', $renderer);
     }
 
     /**
-     * @return array
+     * @return \Iterator<(int | string), mixed>
      * @see tableRendering
      */
-    public function provideTables()
+    public function provideTables(): \Iterator
     {
-        return [[[['column' => 'Doors wide > open'], ['column' => "null \0 bytes FTW"]], '<?xml version="1.0" encoding="UTF-8"?>
+        yield [[['column' => 'Doors wide > open'], ['column' => "null \0 bytes FTW"]], '<?xml version="1.0" encoding="UTF-8"?>
 <table>
   <headers>
     <header>column</header>
@@ -53,10 +52,12 @@ public function provideTables()
   <row>
     <column encoding="base64">bnVsbCAAIGJ5dGVzIEZUVw==</column>
   </row>
-</table>'], [[], '<?xml version="1.0" encoding="UTF-8"?>
+</table>'];
+        yield [[], '<?xml version="1.0" encoding="UTF-8"?>
 <table>
   <!--intentionally left blank, the table is empty-->
-</table>'], [[['Column1' => 'Value A1', 'Column2' => 'A2 is another value that there is'], [1, "multi\nline\nftw"], ['C1 cell here!', new SimpleXMLElement('<r>PHP Magic->toString() test</r>')]], '<?xml version="1.0" encoding="UTF-8"?>
+</table>'];
+        yield [[['Column1' => 'Value A1', 'Column2' => 'A2 is another value that there is'], [1, "multi\nline\nftw"], ['C1 cell here!', new SimpleXMLElement('<r>PHP Magic->toString() test</r>')]], '<?xml version="1.0" encoding="UTF-8"?>
 <table>
   <headers>
     <header>Column1</header>
@@ -76,7 +77,8 @@ public function provideTables()
     <Column1>C1 cell here!</Column1>
     <Column2>PHP Magic-&gt;toString() test</Column2>
   </row>
-</table>'], [[["\x00" => 'foo']], '<?xml version="1.0" encoding="UTF-8"?>
+</table>'];
+        yield [[["\x00" => 'foo']], '<?xml version="1.0" encoding="UTF-8"?>
 <table>
   <headers>
     <header></header>
@@ -84,7 +86,8 @@ public function provideTables()
   <row>
     <_>foo</_>
   </row>
-</table>'], [[['foo' => 'bar'], ['baz', 'buz' => 'here']], '<?xml version="1.0" encoding="UTF-8"?>
+</table>'];
+        yield [[['foo' => 'bar'], ['baz', 'buz' => 'here']], '<?xml version="1.0" encoding="UTF-8"?>
 <table>
   <headers>
     <header>foo</header>
@@ -96,13 +99,10 @@ public function provideTables()
     <foo>baz</foo>
     <buz>here</buz>
   </row>
-</table>']];
+</table>'];
     }
 
-    /**
-     * @test
-     */
-    public function invalidName()
+    public function testInvalidName()
     {
         $this->expectException(DOMException::class);
         $this->expectExceptionMessage("Invalid name '0'");
@@ -111,10 +111,7 @@ public function invalidName()
         $xmlRenderer->render($nullOutput, [['foo']]);
     }
 
-    /**
-     * @test
-     */
-    public function invalidEncoding()
+    public function testInvalidEncoding()
     {
         $this->expectException(RuntimeException::class);
         $this->expectExceptionMessage("Encoding error, only US-ASCII and UTF-8 supported, can not process '");
@@ -124,16 +121,15 @@ public function invalidEncoding()
     }
 
     /**
-     * @test
      * @dataProvider provideTables
      */
-    public function tableRendering($rows, $expected)
+    public function testTableRendering($rows, $expected)
     {
         $xmlRenderer = new XmlRenderer();
         $streamOutput = new StreamOutput(fopen('php://memory', 'wb', false));
 
         $xmlRenderer->render($streamOutput, $rows);
 
-        self::assertEquals($expected . "\n", $this->getOutputBuffer($streamOutput));
+        $this->assertSame($expected . "\n", $this->getOutputBuffer($streamOutput));
     }
 }
diff --git a/tests/N98/Util/DateTimeTest.php b/tests/N98/Util/DateTimeTest.php
index 752e0c143..bbf7928db 100644
--- a/tests/N98/Util/DateTimeTest.php
+++ b/tests/N98/Util/DateTimeTest.php
@@ -1,31 +1,36 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Util;
 
 use PHPUnit\Framework\TestCase;
 use DateTime;
 use DateTimeZone;
 
-class DateTimeTest extends TestCase
+final class DateTimeTest extends TestCase
 {
     /**
-     * @test
-     * @param \DateTime $time1
-     * @param \DateTime $time2
      * @param string $expected
      * @dataProvider getDifferenceAsStringProvider
      */
-    public function getDifferenceAsString(DateTime $time1, DateTime $time2, $expected)
+    public function testGetDifferenceAsString(DateTime $time1, DateTime $time2, $expected)
     {
         $dateTime = new \N98\Util\DateTime();
-        self::assertEquals($expected, $dateTime->getDifferenceAsString($time1, $time2));
+        $this->assertSame($expected, $dateTime->getDifferenceAsString($time1, $time2));
     }
 
     /**
-     * @return array
+     * @return \Iterator<(int | string), mixed>
      */
-    public static function getDifferenceAsStringProvider()
+    public static function getDifferenceAsStringProvider(): \Iterator
     {
-        return [[new DateTime('2013-12-01', new DateTimeZone('UTC')), new DateTime('2013-12-01', new DateTimeZone('UTC')), '0'], [new DateTime('2013-12-01 00:00:00', new DateTimeZone('UTC')), new DateTime('2013-12-01 00:00:01', new DateTimeZone('UTC')), '1s'], [new DateTime('2013-12-01 00:00:00', new DateTimeZone('UTC')), new DateTime('2013-12-01 00:01:01', new DateTimeZone('UTC')), '1m 1s'], [new DateTime('2013-12-01 00:00:00', new DateTimeZone('UTC')), new DateTime('2013-12-01 01:01:01', new DateTimeZone('UTC')), '1h 1m 1s'], [new DateTime('2013-12-01 00:00:00', new DateTimeZone('UTC')), new DateTime('2013-12-02 01:01:01', new DateTimeZone('UTC')), '1d 1h 1m 1s'], [new DateTime('2013-12-01 00:00:00', new DateTimeZone('UTC')), new DateTime('2014-01-02 01:01:01', new DateTimeZone('UTC')), '1M 1d 1h 1m 1s'], [new DateTime('2013-12-01 00:00:00', new DateTimeZone('UTC')), new DateTime('2015-01-02 01:01:01', new DateTimeZone('UTC')), '1Y 1M 1d 1h 1m 1s']];
+        yield [new DateTime('2013-12-01', new DateTimeZone('UTC')), new DateTime('2013-12-01', new DateTimeZone('UTC')), '0'];
+        yield [new DateTime('2013-12-01 00:00:00', new DateTimeZone('UTC')), new DateTime('2013-12-01 00:00:01', new DateTimeZone('UTC')), '1s'];
+        yield [new DateTime('2013-12-01 00:00:00', new DateTimeZone('UTC')), new DateTime('2013-12-01 00:01:01', new DateTimeZone('UTC')), '1m 1s'];
+        yield [new DateTime('2013-12-01 00:00:00', new DateTimeZone('UTC')), new DateTime('2013-12-01 01:01:01', new DateTimeZone('UTC')), '1h 1m 1s'];
+        yield [new DateTime('2013-12-01 00:00:00', new DateTimeZone('UTC')), new DateTime('2013-12-02 01:01:01', new DateTimeZone('UTC')), '1d 1h 1m 1s'];
+        yield [new DateTime('2013-12-01 00:00:00', new DateTimeZone('UTC')), new DateTime('2014-01-02 01:01:01', new DateTimeZone('UTC')), '1M 1d 1h 1m 1s'];
+        yield [new DateTime('2013-12-01 00:00:00', new DateTimeZone('UTC')), new DateTime('2015-01-02 01:01:01', new DateTimeZone('UTC')), '1Y 1M 1d 1h 1m 1s'];
     }
 }
diff --git a/tests/N98/Util/ExecTest.php b/tests/N98/Util/ExecTest.php
index 06896f378..c31de2d62 100644
--- a/tests/N98/Util/ExecTest.php
+++ b/tests/N98/Util/ExecTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Util;
 
 use PHPUnit\Framework\TestCase;
@@ -10,33 +12,24 @@
  *
  * @package N98\Util
  */
-class ExecTest extends TestCase
+final class ExecTest extends TestCase
 {
-    /**
-     * @test
-     */
-    public function commandOnly()
+    public function testCommandOnly()
     {
         Exec::run('echo test', $output, $actual);
 
-        self::assertSame(0, $actual);
+        $this->assertSame(0, $actual);
     }
 
-    /**
-     * @test
-     */
-    public function fullParameters()
+    public function testFullParameters()
     {
         Exec::run('echo test', $commandOutput, $returnCode);
 
-        self::assertEquals(Exec::CODE_CLEAN_EXIT, $returnCode);
-        self::assertStringStartsWith('test', $commandOutput);
+        $this->assertSame(Exec::CODE_CLEAN_EXIT, $returnCode);
+        $this->assertStringStartsWith('test', $commandOutput);
     }
 
-    /**
-     * @test
-     */
-    public function exception()
+    public function testException()
     {
         $this->expectException(RuntimeException::class);
         Exec::run('foobar');
diff --git a/tests/N98/Util/FilesystemTest.php b/tests/N98/Util/FilesystemTest.php
index bbe3e3a42..7202a9a6c 100644
--- a/tests/N98/Util/FilesystemTest.php
+++ b/tests/N98/Util/FilesystemTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 /*
  * this file is part of magerun
  *
@@ -17,16 +19,16 @@
  * @author Aydin Hassan <aydin@hotmail.co.uk>
  * @covers N98\Util\Filesystem
  */
-class FilesystemTest extends TestCase
+final class FilesystemTest extends TestCase
 {
     /**
      * @var Filesystem
      */
-    protected $fileSystem;
+    private $filesystem;
 
     protected function setUp(): void
     {
-        $this->fileSystem = new Filesystem();
+        $this->filesystem = new Filesystem();
     }
 
     public function testRecursiveCopy()
@@ -45,9 +47,9 @@ public function testRecursiveCopy()
         touch($file1);
         touch($file2);
 
-        $this->fileSystem->recursiveCopy($basePath, $dest);
-        self::assertFileExists($dest . '/folder1/file1.txt');
-        self::assertFileExists($dest . '/folder2/file2.txt');
+        $this->filesystem->recursiveCopy($basePath, $dest);
+        $this->assertFileExists($dest . '/folder1/file1.txt');
+        $this->assertFileExists($dest . '/folder2/file2.txt');
 
         //cleanup
         unlink($file1);
@@ -62,14 +64,15 @@ public function testRecursiveCopy()
         rmdir($dest . '/folder2');
         rmdir($dest);
 
-        self::assertFileDoesNotExist($dest . '/folder1/file1.txt');
-        self::assertFileDoesNotExist($dest);
+        $this->assertFileDoesNotExist($dest . '/folder1/file1.txt');
+        $this->assertFileDoesNotExist($dest);
 
         if (!is_dir($tmp . '/a')) {
             mkdir($tmp . '/a');
         }
+
         touch($tmp . '/file1.txt');
-        $this->fileSystem->recursiveCopy($tmp . '/a', $tmp . '/file1.txt');
+        $this->filesystem->recursiveCopy($tmp . '/a', $tmp . '/file1.txt');
         unlink($tmp . '/file1.txt');
         rmdir($tmp . '/a');
     }
@@ -84,7 +87,7 @@ public function testRecursiveCopyWithBlacklist()
         $ignoreMe = $folder1 . '/ignore.me';
         $file2 = $folder2 . '/file2.txt';
         $dest = sys_get_temp_dir() . '/n98_copy_dest';
-        $this->fileSystem->recursiveRemoveDirectory($dest, true);
+        $this->filesystem->recursiveRemoveDirectory($dest, true);
 
         @mkdir($folder1, 0777, true);
         @mkdir($folder2, 0777, true);
@@ -92,10 +95,10 @@ public function testRecursiveCopyWithBlacklist()
         touch($ignoreMe);
         touch($file2);
 
-        $this->fileSystem->recursiveCopy($basePath, $dest, ['ignore.me']);
-        self::assertFileExists($dest . '/folder1/file1.txt');
-        self::assertFileDoesNotExist($dest . '/folder1/ignore.me');
-        self::assertFileExists($dest . '/folder2/file2.txt');
+        $this->filesystem->recursiveCopy($basePath, $dest, ['ignore.me']);
+        $this->assertFileExists($dest . '/folder1/file1.txt');
+        $this->assertFileDoesNotExist($dest . '/folder1/ignore.me');
+        $this->assertFileExists($dest . '/folder2/file2.txt');
 
         //cleanup
         unlink($file1);
@@ -128,12 +131,12 @@ public function testRecursiveDirectoryRemoveUnLinksSymLinks()
         touch($symLinkedFile);
 
         $result = @symlink($symLinked, $basePath . '/symlink');
-        self::assertTrue($result);
+        $this->assertTrue($result);
 
-        $this->fileSystem->recursiveRemoveDirectory($basePath);
+        $this->filesystem->recursiveRemoveDirectory($basePath);
 
-        self::assertFileExists($symLinkedFile);
-        self::assertFileDoesNotExist($basePath);
+        $this->assertFileExists($symLinkedFile);
+        $this->assertFileDoesNotExist($basePath);
     }
 
     public function testRecursiveRemove()
@@ -150,8 +153,8 @@ public function testRecursiveRemove()
         touch($file1);
         touch($file2);
 
-        $this->fileSystem->recursiveRemoveDirectory($basePath);
-        self::assertFileDoesNotExist($basePath);
+        $this->filesystem->recursiveRemoveDirectory($basePath);
+        $this->assertFileDoesNotExist($basePath);
     }
 
     public function testRecursiveRemoveWithTrailingSlash()
@@ -168,13 +171,13 @@ public function testRecursiveRemoveWithTrailingSlash()
         touch($file1);
         touch($file2);
 
-        $this->fileSystem->recursiveRemoveDirectory($basePath . '/');
-        self::assertFileDoesNotExist($basePath);
+        $this->filesystem->recursiveRemoveDirectory($basePath . '/');
+        $this->assertFileDoesNotExist($basePath);
     }
 
     public function testFalseIsReturnedIfDirectoryNotExist()
     {
-        self::assertFalse($this->fileSystem->recursiveRemoveDirectory('not-a-folder'));
+        $this->assertFalse($this->filesystem->recursiveRemoveDirectory('not-a-folder'));
     }
 
     public function testFalseIsReturnedIfDirectoryNotReadable()
@@ -182,7 +185,7 @@ public function testFalseIsReturnedIfDirectoryNotReadable()
         $tmp = sys_get_temp_dir();
         $basePath = $tmp . '/n98_testdir-never-existed';
 
-        self::assertFalse($this->fileSystem->recursiveRemoveDirectory($basePath));
+        $this->assertFalse($this->filesystem->recursiveRemoveDirectory($basePath));
     }
 
     public function testParentIsNotRemovedIfEmptyIsTrue()
@@ -199,10 +202,10 @@ public function testParentIsNotRemovedIfEmptyIsTrue()
         touch($file1);
         touch($file2);
 
-        $this->fileSystem->recursiveRemoveDirectory($basePath, true);
-        self::assertFileExists($basePath);
-        self::assertFileDoesNotExist($folder1);
-        self::assertFileDoesNotExist($folder2);
+        $this->filesystem->recursiveRemoveDirectory($basePath, true);
+        $this->assertFileExists($basePath);
+        $this->assertFileDoesNotExist($folder1);
+        $this->assertFileDoesNotExist($folder2);
     }
 
     /**
@@ -214,14 +217,18 @@ public function testParentIsNotRemovedIfEmptyIsTrue()
     public function testConvertBytesToHumanReadable($bytes, $decimalPlaces, $expected)
     {
         $res = Filesystem::humanFileSize($bytes, $decimalPlaces);
-        self::assertSame($expected, $res);
+        $this->assertSame($expected, $res);
     }
 
     /**
-     * @return array
+     * @return \Iterator<(int | string), mixed>
      */
-    public static function convertedBytesProvider()
+    public static function convertedBytesProvider(): \Iterator
     {
-        return [[20_000_000, 2, '19.07M'], [20_000_000, 3, '19.073M'], [2_000_000_000, 2, '1.86G'], [2, 2, '2.00B'], [2048, 2, '2.00K']];
+        yield [20_000_000, 2, '19.07M'];
+        yield [20_000_000, 3, '19.073M'];
+        yield [2_000_000_000, 2, '1.86G'];
+        yield [2, 2, '2.00B'];
+        yield [2048, 2, '2.00K'];
     }
 }
diff --git a/tests/N98/Util/OperatingSystemTest.php b/tests/N98/Util/OperatingSystemTest.php
index 240390740..9e60cf46f 100644
--- a/tests/N98/Util/OperatingSystemTest.php
+++ b/tests/N98/Util/OperatingSystemTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 /*
  * this file is part of magerun
  *
@@ -16,17 +18,14 @@
  * @package N98\Util
  * @covers N98\Util\OperatingSystem
  */
-class OperatingSystemTest extends TestCase
+final class OperatingSystemTest extends TestCase
 {
-    /**
-     * @test
-     */
-    public function osDetection()
+    public function testOsDetection()
     {
         $matrix = [OperatingSystem::isLinux(), OperatingSystem::isWindows(), OperatingSystem::isMacOs(), OperatingSystem::isNetware()];
 
-        self::assertCount(4, $matrix, 'Number of OSes to check for');
-        self::assertCount(1, array_filter($matrix), 'One OS must be detected');
+        $this->assertCount(4, $matrix, 'Number of OSes to check for');
+        $this->assertCount(1, array_filter($matrix), 'One OS must be detected');
     }
 
     /**
@@ -34,10 +33,10 @@ public function osDetection()
      */
     public function testIsLinux()
     {
-        self::assertTrue(OperatingSystem::isLinux());
-        self::assertFalse(OperatingSystem::isWindows());
-        self::assertFalse(OperatingSystem::isMacOs());
-        self::assertFalse(OperatingSystem::isNetware());
+        $this->assertTrue(OperatingSystem::isLinux());
+        $this->assertFalse(OperatingSystem::isWindows());
+        $this->assertFalse(OperatingSystem::isMacOs());
+        $this->assertFalse(OperatingSystem::isNetware());
     }
 
     /**
@@ -45,10 +44,10 @@ public function testIsLinux()
      */
     public function testIsWindows()
     {
-        self::assertTrue(OperatingSystem::isWindows());
-        self::assertFalse(OperatingSystem::isLinux());
-        self::assertFalse(OperatingSystem::isMacOs());
-        self::assertFalse(OperatingSystem::isNetware());
+        $this->assertTrue(OperatingSystem::isWindows());
+        $this->assertFalse(OperatingSystem::isLinux());
+        $this->assertFalse(OperatingSystem::isMacOs());
+        $this->assertFalse(OperatingSystem::isNetware());
     }
 
     /**
@@ -56,10 +55,10 @@ public function testIsWindows()
      */
     public function testIsMacOs()
     {
-        self::assertTrue(OperatingSystem::isMacOs());
-        self::assertFalse(OperatingSystem::isLinux());
-        self::assertFalse(OperatingSystem::isWindows());
-        self::assertFalse(OperatingSystem::isNetware());
+        $this->assertTrue(OperatingSystem::isMacOs());
+        $this->assertFalse(OperatingSystem::isLinux());
+        $this->assertFalse(OperatingSystem::isWindows());
+        $this->assertFalse(OperatingSystem::isNetware());
     }
 
     /**
@@ -67,27 +66,23 @@ public function testIsMacOs()
      */
     public function testIsNetware()
     {
-        self::assertTrue(OperatingSystem::isNetware());
-        self::assertFalse(OperatingSystem::isLinux());
-        self::assertFalse(OperatingSystem::isWindows());
-        self::assertFalse(OperatingSystem::isMacOs());
+        $this->assertTrue(OperatingSystem::isNetware());
+        $this->assertFalse(OperatingSystem::isLinux());
+        $this->assertFalse(OperatingSystem::isWindows());
+        $this->assertFalse(OperatingSystem::isMacOs());
     }
 
-    /**
-     * @test
-     */
-    public function getCwd()
+    public function testGetCwd()
     {
         $expected = getcwd();
-        self::assertEquals($expected, OperatingSystem::getCwd());
+        $this->assertEquals($expected, OperatingSystem::getCwd());
     }
 
     /**
-     * @test
      * @requires PHP 5.4
      */
-    public function phpBinary()
+    public function testPhpBinary()
     {
-        self::assertEquals(PHP_BINARY, OperatingSystem::getPhpBinary());
+        $this->assertSame(PHP_BINARY, OperatingSystem::getPhpBinary());
     }
 }
diff --git a/tests/N98/Util/StringTypedTest.php b/tests/N98/Util/StringTypedTest.php
index 369379d08..8a0f17bcc 100644
--- a/tests/N98/Util/StringTypedTest.php
+++ b/tests/N98/Util/StringTypedTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 /**
  * this file is part of magerun
  *
@@ -8,7 +10,7 @@
 
 namespace N98\Util;
 
-use PHPUnit\Framework\TestCase as TestCase;
+use PHPUnit\Framework\TestCase;
 
 /**
  * Class StringTypedTest
@@ -16,16 +18,13 @@
  * @package N98\Util
  * @covers N98\Util\StringTyped
  */
-class StringTypedTest extends TestCase
+final class StringTypedTest extends TestCase
 {
-    /**
-     * @test
-     */
-    public function scope()
+    public function testScope()
     {
-        self::assertTrue(StringTyped::parseBoolOption('true'));
+        $this->assertTrue(StringTyped::parseBoolOption('true'));
 
-        self::assertSame('inactive', StringTyped::formatActive(null));
-        self::assertSame('active', StringTyped::formatActive('1'));
+        $this->assertSame('inactive', StringTyped::formatActive(null));
+        $this->assertSame('active', StringTyped::formatActive('1'));
     }
 }
diff --git a/tests/N98/Util/Unicode/CharsetTest.php b/tests/N98/Util/Unicode/CharsetTest.php
index d76fcd938..cc888bbf8 100644
--- a/tests/N98/Util/Unicode/CharsetTest.php
+++ b/tests/N98/Util/Unicode/CharsetTest.php
@@ -1,14 +1,16 @@
 <?php
 
+declare(strict_types=1);
+
 namespace N98\Util\Unicode;
 
 use PHPUnit\Framework\TestCase;
 
-class CharsetTest extends TestCase
+final class CharsetTest extends TestCase
 {
     public function testConvertInteger()
     {
-        self::assertEquals('✖', Charset::convertInteger(Charset::UNICODE_CROSS_CHAR));
-        self::assertEquals('✔', Charset::convertInteger(Charset::UNICODE_CHECKMARK_CHAR));
+        $this->assertSame('✖', Charset::convertInteger(Charset::UNICODE_CROSS_CHAR));
+        $this->assertSame('✔', Charset::convertInteger(Charset::UNICODE_CHECKMARK_CHAR));
     }
 }
diff --git a/tests/N98/Util/VerifyOrDieTest.php b/tests/N98/Util/VerifyOrDieTest.php
index 158096876..08dc72dc1 100644
--- a/tests/N98/Util/VerifyOrDieTest.php
+++ b/tests/N98/Util/VerifyOrDieTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 /*
  * this file is part of magerun
  *
@@ -9,7 +11,7 @@
 namespace N98\Util;
 
 use InvalidArgumentException;
-use PHPUnit\Framework\TestCase as TestCase;
+use PHPUnit\Framework\TestCase;
 use RuntimeException;
 
 /**
@@ -17,56 +19,41 @@
  *
  * @package N98\Util
  */
-class VerifyOrDieTest extends TestCase
+final class VerifyOrDieTest extends TestCase
 {
-    /**
-     * @test a portable filename passes
-     */
-    public function portableFilename()
+    public function testPortableFilename()
     {
-        self::assertSame('example.txt', VerifyOrDie::filename('example.txt'));
+        $this->assertSame('example.txt', VerifyOrDie::filename('example.txt'));
 
-        self::assertSame('.hidden', VerifyOrDie::filename('.hidden'));
+        $this->assertSame('.hidden', VerifyOrDie::filename('.hidden'));
     }
 
-    /**
-     * @test user-message for verification
-     */
-    public function userMessage()
+    public function testUserMessage()
     {
         $message = sprintf('Database name %s is not portable', var_export('-fail', true));
         try {
             VerifyOrDie::filename('-fail', $message);
             self::fail('An expected exception has not been thrown.');
         } catch (RuntimeException $runtimeException) {
-            self::assertSame($message, $runtimeException->getMessage());
+            $this->assertSame($message, $runtimeException->getMessage());
         }
     }
 
-    /**
-     * @test a filename must have at least one byte
-     */
-    public function zeroLengthFilename()
+    public function testZeroLengthFilename()
     {
         $this->expectException(\RuntimeException::class);
         $this->expectExceptionMessage('Filename is zero-length string');
         VerifyOrDie::filename('');
     }
 
-    /**
-     * @test
-     */
-    public function invalidArugment()
+    public function testInvalidArugment()
     {
         $this->expectException(InvalidArgumentException::class);
         $this->expectExceptionMessage('Parameter basename must be of type string, NULL given');
         VerifyOrDie::filename(null);
     }
 
-    /**
-     * @test a filename must not start with a dash
-     */
-    public function startWithDashFilename()
+    public function testStartWithDashFilename()
     {
         $this->expectException(\RuntimeException::class);
         $this->expectExceptionMessage("Filename '-rf' starts with a dash");
@@ -74,10 +61,9 @@ public function startWithDashFilename()
     }
 
     /**
-     * @test
      * @dataProvider provideNonPortableFilenames
      */
-    public function nonPortableFilenameThrowsException($filename)
+    public function testNonPortableFilenameThrowsException($filename)
     {
         $this->expectException(\RuntimeException::class);
         $this->expectExceptionMessage('is not portable');
@@ -87,8 +73,10 @@ public function nonPortableFilenameThrowsException($filename)
     /**
      * @see nonPortableFilenameThrowsException
      */
-    public function provideNonPortableFilenames()
+    public function provideNonPortableFilenames(): \Iterator
     {
-        return [['no-slash-/-in.there'], ['windoze-limits-<>:"/\\|?*'], ['lets-keep-spaces   out']];
+        yield ['no-slash-/-in.there'];
+        yield ['windoze-limits-<>:"/\\|?*'];
+        yield ['lets-keep-spaces   out'];
     }
 }
diff --git a/tests/N98/Util/WindowsSystemTest.php b/tests/N98/Util/WindowsSystemTest.php
index f63101af4..96ac2a976 100644
--- a/tests/N98/Util/WindowsSystemTest.php
+++ b/tests/N98/Util/WindowsSystemTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 /**
  * this file is part of magerun
  *
@@ -16,38 +18,41 @@
  * @package N98\Util
  * @requires OS win
  */
-class WindowsSystemTest extends TestCase
+final class WindowsSystemTest extends TestCase
 {
-    /**
-     * @test
-     */
-    public function isProgramInstalled()
+    public function testIsProgramInstalled()
     {
-        self::assertTrue(WindowsSystem::isProgramInstalled('notepad'));
+        $this->assertTrue(WindowsSystem::isProgramInstalled('notepad'));
 
-        self::assertFalse(WindowsSystem::isProgramInstalled('notepad-that-never-made-it-into-windows-kernel'));
+        $this->assertFalse(WindowsSystem::isProgramInstalled('notepad-that-never-made-it-into-windows-kernel'));
 
-        self::assertFalse(WindowsSystem::isProgramInstalled('invalid\\command*name|thisis'));
+        $this->assertFalse(WindowsSystem::isProgramInstalled('invalid\\command*name|thisis'));
     }
 
     /**
      * @see isExecutableName
-     * @return array
+     * @return \Iterator<(int | string), mixed>
      */
-    public function provideExecutableNames()
+    public function provideExecutableNames(): \Iterator
     {
-        return [['notepad', false], ['notepad.com', true], ['notepad.exe', true], ['notepad.exe.exe', true], ['notepad.eXe', true], ['notepad.EXE', true], ['notepad.bat', true], ['notepad.txt', false]];
+        yield ['notepad', false];
+        yield ['notepad.com', true];
+        yield ['notepad.exe', true];
+        yield ['notepad.exe.exe', true];
+        yield ['notepad.eXe', true];
+        yield ['notepad.EXE', true];
+        yield ['notepad.bat', true];
+        yield ['notepad.txt', false];
     }
 
     /**
-     * @test
      *
      * @param string $name
      * @param bool $expected
      * @dataProvider provideExecutableNames
      */
-    public function isExecutableName($name, $expected)
+    public function testIsExecutableName($name, $expected)
     {
-        self::assertSame($expected, WindowsSystem::isExecutableName($name), $name);
+        $this->assertSame($expected, WindowsSystem::isExecutableName($name), $name);
     }
 }