diff --git a/src/HttpHandler/Guzzle6HttpHandler.php b/src/HttpHandler/Guzzle6HttpHandler.php
index 012d34388..cfdbcb183 100644
--- a/src/HttpHandler/Guzzle6HttpHandler.php
+++ b/src/HttpHandler/Guzzle6HttpHandler.php
@@ -65,7 +65,7 @@ public function __invoke(RequestInterface $request, array $options = [])
         $response = $this->client->send($request, $options);
 
         if ($this->logger) {
-           $this->responseLog($response, $requestEvent);
+            $this->responseLog($response, $requestEvent);
         }
 
         return $response;
@@ -120,6 +120,11 @@ public function requestLog(RequestInterface $request, array $options): RpcLogEve
         return $requestEvent;
     }
 
+    /**
+     * @internal
+     * @param RequestInterface $request
+     * @param array<mixed> $options
+     */
     public function responseLog(ResponseInterface $response, RpcLogEvent $requestEvent): void
     {
         $responseEvent = new RpcLogEvent($requestEvent->milliseconds);
diff --git a/src/Logging/LoggingTrait.php b/src/Logging/LoggingTrait.php
index 97c51368a..2441a9bd7 100644
--- a/src/Logging/LoggingTrait.php
+++ b/src/Logging/LoggingTrait.php
@@ -126,10 +126,12 @@ private function getJwtToken(array $headers): null|array
      */
     private function truncatePayload(null|string $payload): null|string
     {
-        if (is_null($payload) || strlen($payload) <= 500) {
+        $maxLength = 500;
+
+        if (is_null($payload) || strlen($payload) <= $maxLength) {
             return $payload;
         }
 
-        return substr($payload, 0, 500) . '...';
+        return substr($payload, 0, $maxLength) . '...';
     }
 }
diff --git a/tests/ApplicationDefaultCredentialsTest.php b/tests/ApplicationDefaultCredentialsTest.php
index 89a4afafa..cf6b542d5 100644
--- a/tests/ApplicationDefaultCredentialsTest.php
+++ b/tests/ApplicationDefaultCredentialsTest.php
@@ -793,6 +793,11 @@ public function testGetDefaultLoggerReturnsNullIfNotEnvVar()
         $logger = ApplicationDefaultCredentials::getDefaultLogger();
 
         $this->assertNull($logger);
+
+        putenv($this::SDK_DEBUG_ENV_VAR . '=');
+        $logger = ApplicationDefaultCredentials::getDefaultLogger();
+
+        $this->assertNull($logger);
     }
 
     public function testGetDefaultLoggerRaiseAWarningIfMisconfiguredAndReturnsNull()
diff --git a/tests/HttpHandler/Guzzle7HttpHandlerTest.php b/tests/HttpHandler/Guzzle7HttpHandlerTest.php
index 97cb8688d..53147be3a 100644
--- a/tests/HttpHandler/Guzzle7HttpHandlerTest.php
+++ b/tests/HttpHandler/Guzzle7HttpHandlerTest.php
@@ -74,11 +74,9 @@ public function testLoggerDoesNotGetsCalledIfLoggerIsNotPassed()
         $request = new Request('GET', 'https://domain.tld');
         $options = ['key' => 'value'];
 
-        /**
-         * @var LoggerInterface $mockLogger
-         * @var ClientInterface $mockClient
-         */
         $handler = new Guzzle7HttpHandler($this->client->reveal());
         $handler->async($request, $options)->wait();
+
+        $this->expectOutputString('');
     }
 }
diff --git a/tests/Logging/LoggingTraitTest.php b/tests/Logging/LoggingTraitTest.php
index edc85b5bd..211fc4d0f 100644
--- a/tests/Logging/LoggingTraitTest.php
+++ b/tests/Logging/LoggingTraitTest.php
@@ -25,11 +25,23 @@
 
 class LoggingTraitTest extends BaseTest
 {
-    private MockClassWithLogger $loggerContainer;
+    private $loggerContainer;
 
     public function setUp(): void
     {
-        $this->loggerContainer = new MockClassWithLogger();
+        $this->loggerContainer = new class() {
+            use LoggingTrait {
+                logRequest as public;
+                logResponse as public;
+            }
+
+            private LoggerInterface $logger;
+
+            public function __construct()
+            {
+                $this->logger = new StdOutLogger();
+            }
+        };
     }
 
     public function testLogRequest()