diff --git a/.gitignore b/.gitignore
index 6367e5f..841c65c 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,7 +1,25 @@
+tmp/*
+[Cc]onfig/core.php
+[Cc]onfig/database.php
+app/tmp/*
+app/[Cc]onfig/core.php
+app/[Cc]onfig/database.php
+!empty
 /vendor/*
-/config/app.php
-/tmp/*
-/logs/*
+
+# OS
+.DS_Store
+.AppleDouble
+.LSOverride
+Icon?
+._*
+.Spotlight-V100
+.Trashes
+.AppleDB
+.AppleDesktop
+Network Trash Folder
+Temporary Items
+.apdisk
 
 # Ignore the composer lock file-- it should never be included in a distributed package.
 /composer.lock
diff --git a/src/Model/Behavior/CreatorModifierBehavior.php b/src/Model/Behavior/CreatorModifierBehavior.php
index 755a875..0755bb6 100644
--- a/src/Model/Behavior/CreatorModifierBehavior.php
+++ b/src/Model/Behavior/CreatorModifierBehavior.php
@@ -1,16 +1,29 @@
 <?php
+/**
+ * CreatorModifierBehavior is a tool to set a `creator_id` and `modifier_id`
+ * on records being saved.
+ */
 namespace CreatorModifier\Model\Behavior;
 
 use Cake\Event\Event;
+use Cake\Log\LogTrait;
+use Cake\Network\Request;
 use Cake\ORM\Behavior;
 use Cake\ORM\Entity;
+use \RuntimeException;
+use \UnexpectedValueException;
 
 /**
- * CreatorModifierBehavior - Adds the ability to use the Session provided User.primary_key
+ * \CreatorModifier\Model\Behavior\CreatorModifierBehavior
+ *
+ * Adds the ability to use the Session provided User.primary_key
  * value to assign to the creator_id and modifier_id on saving an Entity.
  */
 class CreatorModifierBehavior extends Behavior {
 
+	// Add logging in the event of a failure with the session.
+	use LogTrait;
+
 	/**
 	 * These are merged with user-provided config when the behavior is used.
 	 *
@@ -70,7 +83,7 @@ public function handleEvent(Event $event, Entity $entity) {
 
 		foreach ($events[$eventName] as $field => $when) {
 			if (!in_array($when, ['always', 'new', 'existing'])) {
-				throw new \UnexpectedValueException(
+				throw new UnexpectedValueException(
 					sprintf('When should be one of "always", "new" or "existing". The passed value "%s" is invalid', $when)
 				);
 			}
@@ -147,15 +160,6 @@ protected function updateField(Entity $entity, $field) {
 		$entity->set($field, $this->getUserId());
 	}
 
-	/**
-	 * Factory method for the Request object.
-	 *
-	 * @return \Cake\Network\Request New instance of the Request object.
-	 */
-	protected function newRequest() {
-		return new \Cake\Network\Request();
-	}
-
 	/**
 	 * Return the User.id grabbed from the Session information.
 	 *
@@ -167,8 +171,25 @@ protected function sessionUserId() {
 
 		if ($request->session()->started()) {
 			$userId = $request->session()->read($this->_config['sessionUserIdKey']);
+		} else {
+			$this->log('The Session is not started. This typically means a User is not logged in. In this case there is no Session value for the currently active User and therefore we will set the `creator_id` and `modifier_id` to a null value. As a fallback, we are manually starting the session and reading the `$this->_config[sessionUserIdKey]` value, which is probably not correct.', 'debug');
+			try {
+				$request->session()->start();
+				$userId = $request->session()->read($this->_config['sessionUserIdKey']);
+			} catch (RuntimeException $e) {
+			}
 		}
 
 		return $userId;
 	}
+
+	/**
+	 * Factory method for the Request object.
+	 *
+	 * @return \Cake\Network\Request New instance of the Request object.
+	 * @codeCoverageIgnore Don't test PHP's ability to use new.
+	 */
+	protected function newRequest() {
+		return new Request();
+	}
 }
diff --git a/tests/TestCase/Model/Behavior/CreatorModifierBehaviorTest.php b/tests/TestCase/Model/Behavior/CreatorModifierBehaviorTest.php
index 258cfe6..9e94976 100644
--- a/tests/TestCase/Model/Behavior/CreatorModifierBehaviorTest.php
+++ b/tests/TestCase/Model/Behavior/CreatorModifierBehaviorTest.php
@@ -1,4 +1,7 @@
 <?php
+/**
+ * Tests for the CreatorModifierBehavior Class.
+ */
 namespace CreatorModifier\Test\TestCase\Model\Behavior;
 
 use Cake\Event\Event;
@@ -6,12 +9,32 @@
 use Cake\ORM\TableRegistry;
 use Cake\TestSuite\TestCase;
 use CreatorModifier\Model\Behavior\CreatorModifierBehavior;
+use \RuntimeException;
 
 /**
- * CreatorModifierBehaviorTest Class
+ * \CreatorModifier\Test\TestCase\Model\Behavior\TestCreatorModifierBehavior
+ *
+ * Expose the protected methods for the CreatorModifierBehavior class for unit
+ * testing.
  */
-class CreatorModifierBehaviorTest extends TestCase {
+class TestCreatorModifierBehavior extends CreatorModifierBehavior {
+	public function updateField(Entity $entity, $field) {
+		return parent::updateField($entity, $field);
+	}
 
+	public function sessionUserId() {
+		return parent::sessionUserId();
+	}
+}
+
+/**
+ * \CreatorModifier\Test\TestCase\Model\Behavior\CreatorModifierBehaviorTest
+ *
+ * Tests for the CreatorModifierBehavior class.
+ *
+ * @coversDefaultClass \CreatorModifier\Model\Behavior\CreatorModifierBehavior
+ */
+class CreatorModifierBehaviorTest extends TestCase {
 	/**
 	 * Mocked User UUID Value
 	 *
@@ -24,9 +47,7 @@ class CreatorModifierBehaviorTest extends TestCase {
 	 *
 	 * @var array
 	 */
-	public $fixtures = [
-		//'CreatorModifier.users'
-	];
+	public $fixtures = [];
 
 	/**
 	 * Setup the Tests
@@ -136,7 +157,8 @@ public function testCreatorIdNotNew() {
 	}
 
 	/**
-	 * Test when the modifier id is absent
+	 * Test what happens when everything works and a modifier_id value for the
+	 * Entity is not yet set.
 	 *
 	 * @return void
 	 * @triggers Model.beforeSave
@@ -156,7 +178,8 @@ public function testModifierIdAbsent() {
 	}
 
 	/**
-	 * testModifiedPresent
+	 * Test what happens when everything works and a modifier_id value for the
+	 * Entity is already set.
 	 *
 	 * @return void
 	 * @triggers Model.beforeSave
@@ -180,7 +203,7 @@ public function testModifierIdPresent() {
 	}
 
 	/**
-	 * testInvalidEventConfig
+	 * Test what happens when we setup invalid configuration for an Event.
 	 *
 	 * @expectedException \UnexpectedValueException
 	 * @expectedExceptionMessage When should be one of "always", "new" or "existing". The passed value "fat fingers" is invalid
@@ -198,7 +221,7 @@ public function testInvalidEventConfig() {
 	}
 
 	/**
-	 * testGetTimestamp
+	 * Test the method ::getUserId, should return our mocked return.
 	 *
 	 * @return void
 	 */
@@ -213,9 +236,9 @@ public function testGetUserId() {
 	}
 
 	/**
-	 * test that get user id persists
+	 * Test that getUserId persists and returns the same value for multiple calls.
 	 *
-	 * @depends testGetTimestamp
+	 * @depends testGetUserId
 	 * @return void
 	 */
 	public function testGetUserIdPersists($behavior) {
@@ -230,7 +253,7 @@ public function testGetUserIdPersists($behavior) {
 	}
 
 	/**
-	 * testCreatedOrModified
+	 * Test the Behavior in the event everything works normally.
 	 *
 	 * @return void
 	 */
@@ -249,7 +272,38 @@ public function testCreatedOrModified() {
 	}
 
 	/**
-	 * testTouchNoop
+	 * Test the Behavior when an event is fired that doesn't have any data set
+	 * for it from the configs.
+	 *
+	 * @return void
+	 */
+	public function testCreatedOrModifiedEmptyEvent() {
+		$table = $this->getMock('Cake\ORM\Table');
+		$config = [
+			'events' => [
+				'Model.beforeSave' => [],
+			],
+		];
+
+		$this->Behavior = $this->getMock(
+			'\CreatorModifier\Model\Behavior\CreatorModifierBehavior',
+			['sessionUserId'],
+			[$table, $config]
+		);
+		$this->Behavior->expects($this->any())
+			->method('sessionUserId')
+			->will($this->returnValue($this->mockedUserUUID));
+
+		$entity = new Entity(['username' => 'timestamp test']);
+		$return = $this->Behavior->createdOrModifed($entity);
+		$this->assertFalse($return, 'createdOrModifed is expected to do nothing and return false');
+		$this->assertNull($entity->modifier_id, 'modifier_id field is NOT expected to change');
+		$this->assertNull($entity->creator_id, 'creator_id field is NOT expected to change');
+	}
+
+	/**
+	 * Test the CreatedModifiedBehavior in the event that nothing is expected to
+	 * happen.
 	 *
 	 * @return void
 	 */
@@ -280,7 +334,7 @@ public function testCreatedOrModifiedNoop() {
 	}
 
 	/**
-	 * testTouchCustomEvent
+	 * Test handling a custom fired event.
 	 *
 	 * @return void
 	 */
@@ -314,4 +368,224 @@ public function testCreatedOrModifiedCustomEvent() {
 			'Creator_id field is NOT expected to change'
 		);
 	}
+
+	/**
+	 * Test the ::updateField method when the field is marked as dirty.
+	 *
+	 * @return void
+	 */
+	public function testUpdateFieldIsDirty() {
+		$existingValue = '54108b70-a178-4590-9df4-1a900a00020f';
+		$field = 'modifier_id';
+		$entity = $this->getMock(
+			'\Cake\ORM\Entity',
+			['dirty'],
+			[['name' => 'Foo', $field => $existingValue]]
+		);
+		$entity->expects($this->once())
+			->method('dirty')
+			->with($field)
+			->will($this->returnValue(true));
+
+		$table = $this->getMock('Cake\ORM\Table');
+		$behavior = $this->getMock(
+			'\CreatorModifier\Test\TestCase\Model\Behavior\TestCreatorModifierBehavior',
+			['getUserId'],
+			[$table]
+		);
+		$behavior->expects($this->never())
+			->method('getUserId')
+			->will($this->returnValue($this->mockedUserUUID));
+
+		$return = $behavior->updateField($entity, 'modifier_id');
+		$this->assertNull(
+			$return,
+			'When attempting to update a field marked already dirty, ::updateField returns null and does nothing.'
+		);
+	}
+
+	/**
+	 * Test the ::updateField method when the field is marked as dirty.
+	 *
+	 * @return void
+	 */
+	public function testUpdateFieldIsClean() {
+		$existingValue = '54108b70-a178-4590-9df4-1a900a00020f';
+		$field = 'modifier_id';
+		$entity = $this->getMock(
+			'\Cake\ORM\Entity',
+			['dirty', 'set'],
+			[['name' => 'Foo', $field => $existingValue]]
+		);
+		$entity->expects($this->once())
+			->method('dirty')
+			->with($field)
+			->will($this->returnValue(false));
+		$entity->expects($this->once())
+			->method('set')
+			->with($field, $this->mockedUserUUID)
+			->will($this->returnValue(true));
+
+		$table = $this->getMock('\Cake\ORM\Table');
+		$behavior = $this->getMock(
+			'\CreatorModifier\Test\TestCase\Model\Behavior\TestCreatorModifierBehavior',
+			['getUserId'],
+			[$table]
+		);
+		$behavior->expects($this->once())
+			->method('getUserId')
+			->will($this->returnValue($this->mockedUserUUID));
+
+		$return = $behavior->updateField($entity, 'modifier_id');
+		$this->assertNull(
+			$return,
+			'When attempting to update a field marked clean, ::updateField returns null and sets the return from ::getUserId to the field for the Entity.'
+		);
+	}
+
+	/**
+	 * Test ::sessionUserId when the session exists, is started and returns a value.
+	 *
+	 * @return void
+	 */
+	public function testSessionUserIdSessionExists() {
+		$request = $this->getMock(
+			'\Cake\Network\Request',
+			['session', 'started', 'read']
+		);
+		$request->expects($this->any())
+			->method('session')
+			->with()
+			->will($this->returnSelf());
+		$request->expects($this->once())
+			->method('started')
+			->with()
+			->will($this->returnValue(true));
+		$request->expects($this->once())
+			->method('read')
+			->with('Auth.User.id')
+			->will($this->returnValue($this->mockedUserUUID));
+
+		$table = $this->getMock('\Cake\ORM\Table');
+
+		$behavior = $this->getMock(
+			'\CreatorModifier\Test\TestCase\Model\Behavior\TestCreatorModifierBehavior',
+			['newRequest'],
+			[$table]
+		);
+		$behavior->expects($this->once())
+			->method('newRequest')
+			->with()
+			->will($this->returnValue($request));
+
+		$output = $behavior->sessionUserId();
+		$this->assertEquals(
+			$this->mockedUserUUID,
+			$output,
+			'On the session being started and returns a mocked value, that mocked value should be returned.'
+		);
+	}
+
+	/**
+	 * Test ::sessionUserId when the session is not started.
+	 *
+	 * @return void
+	 */
+	public function testSessionUserIdSessionNotStarted() {
+		$request = $this->getMock(
+			'\Cake\Network\Request',
+			['session', 'started', 'read', 'start']
+		);
+		$request->expects($this->any())
+			->method('session')
+			->with()
+			->will($this->returnSelf());
+		$request->expects($this->once())
+			->method('started')
+			->with()
+			->will($this->returnValue(false));
+		$request->expects($this->once())
+			->method('start')
+			->with()
+			->will($this->returnValue(true));
+		$request->expects($this->once())
+			->method('read')
+			->with('Auth.User.id')
+			->will($this->returnValue($this->mockedUserUUID));
+
+		$table = $this->getMock('\Cake\ORM\Table');
+
+		$behavior = $this->getMock(
+			'\CreatorModifier\Test\TestCase\Model\Behavior\TestCreatorModifierBehavior',
+			['newRequest', 'log'],
+			[$table]
+		);
+		$behavior->expects($this->once())
+			->method('newRequest')
+			->with()
+			->will($this->returnValue($request));
+		$behavior->expects($this->once())
+			->method('log')
+			->with($this->anything(), 'debug')
+			->will($this->returnValue(true));
+
+		$output = $behavior->sessionUserId();
+		$this->assertEquals(
+			$this->mockedUserUUID,
+			$output,
+			'On the session not being already started and then manually started and returns a mocked value, that mocked value should be returned.'
+		);
+	}
+
+	/**
+	 * Test ::sessionUserId when the session is not started.
+	 *
+	 * @return void
+	 */
+	public function testSessionUserIdSessionNotStartedStartingThrowsException() {
+		$exception = new RuntimeException();
+
+		$request = $this->getMock(
+			'\Cake\Network\Request',
+			['session', 'started', 'read', 'start']
+		);
+		$request->expects($this->any())
+			->method('session')
+			->with()
+			->will($this->returnSelf());
+		$request->expects($this->once())
+			->method('started')
+			->with()
+			->will($this->returnValue(false));
+		$request->expects($this->once())
+			->method('start')
+			->with()
+			->will($this->throwException($exception));
+		$request->expects($this->never())
+			->method('read')
+			->with('Auth.User.id')
+			->will($this->returnValue($this->mockedUserUUID));
+
+		$table = $this->getMock('\Cake\ORM\Table');
+
+		$behavior = $this->getMock(
+			'\CreatorModifier\Test\TestCase\Model\Behavior\TestCreatorModifierBehavior',
+			['newRequest', 'log'],
+			[$table]
+		);
+		$behavior->expects($this->once())
+			->method('newRequest')
+			->with()
+			->will($this->returnValue($request));
+		$behavior->expects($this->once())
+			->method('log')
+			->with($this->anything(), 'debug')
+			->will($this->returnValue(true));
+
+		$output = $behavior->sessionUserId();
+		$this->assertNull(
+			$output,
+			'On the session not being started, a `null` value should be returned.'
+		);
+	}
 }