diff --git a/core/modules/migrate_drupal/tests/src/source/d6/BlockTest.php b/core/modules/migrate_drupal/tests/src/source/d6/BlockTest.php
index 2a02af9..052abee 100644
--- a/core/modules/migrate_drupal/tests/src/source/d6/BlockTest.php
+++ b/core/modules/migrate_drupal/tests/src/source/d6/BlockTest.php
@@ -94,13 +94,6 @@ public static function getInfo() {
     );
   }
 
-  /**
-   * {@inheritdoc}
-   */
-  public function testRetrieval() {
-    // FakeSelect does not support multiple source identifiers, can not test.
-  }
-
 }
 
 namespace Drupal\migrate_drupal\Tests\source\d6;
diff --git a/core/modules/migrate_drupal/tests/src/source/d6/FieldInstanceTest.php b/core/modules/migrate_drupal/tests/src/source/d6/FieldInstanceTest.php
index 3c8abcf..d88421d 100644
--- a/core/modules/migrate_drupal/tests/src/source/d6/FieldInstanceTest.php
+++ b/core/modules/migrate_drupal/tests/src/source/d6/FieldInstanceTest.php
@@ -106,13 +106,6 @@ public static function getInfo() {
     );
   }
 
-  /**
-   * {@inheritdoc}
-   */
-  public function testRetrieval() {
-    // FakeSelect does not support multiple source identifiers, can not test.
-  }
-
 }
 namespace Drupal\migrate_drupal\Tests\source\d6;
 
diff --git a/core/modules/migrate_drupal/tests/src/source/d6/NodeRevisionTest.php b/core/modules/migrate_drupal/tests/src/source/d6/NodeRevisionTest.php
deleted file mode 100644
index d895ed5..0000000
--- a/core/modules/migrate_drupal/tests/src/source/d6/NodeRevisionTest.php
+++ /dev/null
@@ -1,362 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\migrate_drupal\Tests\source\d6\NodeRevisionTest.
- */
-
-namespace Drupal\migrate_drupal\Tests\source\d6;
-
-use Drupal\migrate\Tests\MigrateSqlSourceTestCase;
-
-/**
- * Tests the Drupal 6 node revision source.
- *
- * @group migrate_drupal
- * @group Drupal
- */
-class NodeRevisionTest extends MigrateSqlSourceTestCase {
-
-  const PLUGIN_CLASS = 'Drupal\migrate_drupal\Plugin\migrate\source\d6\NodeRevision';
-
-  // The fake Migration configuration entity.
-  protected $migrationConfiguration = array(
-    'id' => 'test',
-    // Leave it empty for now.
-    'idlist' => array(),
-    // The fake configuration for the source.
-    'source' => array(
-      'node_type' => 'page',
-      'plugin' => 'd6_node_revision',
-      'bundle' => 'page',
-    ),
-    'sourceIds' => array(
-      'vid' => array(
-        'alias' => 'v',
-      ),
-    ),
-    'destinationIds' => array(
-      'vid' => array(
-        // This is where the field schema would go.
-      ),
-    ),
-  );
-
-  protected $expectedResults = array(
-    array(
-      // Node fields.
-      'nid' => 1,
-      'type' => 'page',
-      'language' => 'en',
-      'status' => 1,
-      'created' => 1279051598,
-      'changed' => 1279051598,
-      'comment' => 2,
-      'promote' => 1,
-      'moderate' => 0,
-      'sticky' => 0,
-      'tnid' => 0,
-      'translate' => 0,
-      // Node revision fields.
-      'vid' => 1,
-      'uid' => 1,
-      'title' => 'title for revision 1 (node 1)',
-      'body' => 'body for revision 1 (node 1)',
-      'teaser' => 'teaser for revision 1 (node 1)',
-      'log' => 'log for revision 1 (node 1)',
-      'format' => 1,
-      'field_test_one_value' => 'text for node 1',
-      'field_test_two' => array(
-        'test field node 1, value 1',
-        'test field node 1, value 2',
-      ),
-
-      // This is just to help with databaseContents and gets unset later.
-      'fields' => array(
-        'field_test_one' => 'text for node 1',
-      ),
-    ),
-    array(
-      // Node fields.
-      'nid' => 1,
-      'type' => 'page',
-      'language' => 'en',
-      'status' => 1,
-      'created' => 1279051598,
-      'changed' => 1279051598,
-      'comment' => 2,
-      'promote' => 1,
-      'moderate' => 0,
-      'sticky' => 0,
-      'tnid' => 0,
-      'translate' => 0,
-      // Node revision fields.
-      'vid' => 3,
-      'uid' => 1,
-      'title' => 'title for revision 3 (node 1)',
-      'body' => 'body for revision 3 (node 1)',
-      'teaser' => 'teaser for revision 3 (node 1)',
-      'log' => 'log for revision 3 (node 1)',
-      'format' => 1,
-      'field_test_one_value' => 'text for node 1',
-      'field_test_two' => array(
-        'test field node 1, value 1',
-        'test field node 1, value 2',
-      ),
-
-      // This is just to help with databaseContents and gets unset later.
-      'fields' => array(
-        'field_test_one' => 'text for node 1',
-      ),
-    ),
-    array(
-      // Node fields.
-      'nid' => 1,
-      'type' => 'page',
-      'language' => 'en',
-      'status' => 1,
-      'created' => 1279051598,
-      'changed' => 1279051598,
-      'comment' => 2,
-      'promote' => 1,
-      'moderate' => 0,
-      'sticky' => 0,
-      'tnid' => 0,
-      'translate' => 0,
-      // Node revision fields.
-      'vid' => 4,
-      'uid' => 1,
-      'title' => 'title for revision 4 (node 1)',
-      'body' => 'body for revision 4 (node 1)',
-      'teaser' => 'teaser for revision 4 (node 1)',
-      'log' => 'log for revision 4 (node 1)',
-      'format' => 1,
-      'field_test_one_value' => 'text for node 1',
-      'field_test_two' => array(
-        'test field node 1, value 1',
-        'test field node 1, value 2',
-      ),
-      // This is just to help with databaseContents and gets unset later.
-      'fields' => array(
-        'field_test_one' => 'text for node 1',
-      ),
-    ),
-    array(
-      // Node fields.
-      'nid' => 2,
-      'type' => 'page',
-      'language' => 'en',
-      'status' => 1,
-      'created' => 1279290908,
-      'changed' => 1279308993,
-      'comment' => 0,
-      'promote' => 1,
-      'moderate' => 0,
-      'sticky' => 0,
-      'tnid' => 0,
-      'translate' => 0,
-      // Node revision fields.
-      'vid' => 2,
-      'uid' => 1,
-      'title' => 'title for revision 2 (node 2)',
-      'body' => 'body for revision 2 (node 2)',
-      'teaser' => 'teaser for revision 2 (node 2)',
-      'log' => 'log for revision 2 (node 2)',
-      'format' => 1,
-      'field_test_two' => array(
-        'test field node 2',
-      ),
-
-      // This is just to help with databaseContents and gets unset later.
-      'fields' => array(
-        'field_test_one' => 'text for node 2',
-      ),
-    ),
-  );
-
-  protected $fields = array(
-    'field_test_one' => array(
-      'content_node_field_instance' => array(
-        'field_name' => 'field_test_one',
-        'type_name' => 'page',
-        'weight' => 1,
-        'label' => 'Field Label One',
-        'widget_type' => 'text_textfield',
-        'widget_settings' => 'a:4:{s:4:"rows";i:5;s:4:"size";s:2:"60";s:13:"default_value";a:1:{i:0;a:2:{s:5:"value";s:0:"";s:14:"_error_element";s:42:"default_value_widget][field_test][0][value";}}s:17:"default_value_php";N;}',
-        'display_settings' => 'a:6:{s:6:"weight";s:2:"31";s:6:"parent";s:0:"";s:5:"label";a:1:{s:6:"format";s:5:"above";}s:6:"teaser";a:2:{s:6:"format";s:7:"default";s:7:"exclude";i:0;}s:4:"full";a:2:{s:6:"format";s:7:"default";s:7:"exclude";i:0;}i:4;a:2:{s:6:"format";s:7:"default";s:7:"exclude";i:0;}}',
-        'description' => '',
-        'widget_module' => 'text',
-        'widget_active' => 1,
-      ),
-      'content_node_field' => array(
-        'field_name' => 'field_test_one',
-        'type' => 'text',
-        'global_settings' => 'a:4:{s:15:"text_processing";s:1:"0";s:10:"max_length";s:0:"";s:14:"allowed_values";s:0:"";s:18:"allowed_values_php";s:0:"";}',
-        'required' => 0,
-        'multiple' => 0,
-        'db_storage' => 1,
-        'module' => 'text',
-        'db_columns' => 'a:1:{s:5:"value";a:5:{s:4:"type";s:4:"text";s:4:"size";s:3:"big";s:8:"not null";b:0;s:8:"sortable";b:1;s:5:"views";b:1;}}',
-        'active' => 1,
-        'locked' => 0,
-      ),
-    ),
-    'field_test_two' => array(
-      'content_node_field_instance' => array(
-        'field_name' => 'field_test_two',
-        'type_name' => 'page',
-        'weight' => 1,
-        'label' => 'Field Label One',
-        'widget_type' => 'text_textfield',
-        'widget_settings' => 'a:4:{s:4:"rows";i:5;s:4:"size";s:2:"60";s:13:"default_value";a:1:{i:0;a:2:{s:5:"value";s:0:"";s:14:"_error_element";s:42:"default_value_widget][field_test][0][value";}}s:17:"default_value_php";N;}',
-        'display_settings' => 'a:6:{s:6:"weight";s:2:"31";s:6:"parent";s:0:"";s:5:"label";a:1:{s:6:"format";s:5:"above";}s:6:"teaser";a:2:{s:6:"format";s:7:"default";s:7:"exclude";i:0;}s:4:"full";a:2:{s:6:"format";s:7:"default";s:7:"exclude";i:0;}i:4;a:2:{s:6:"format";s:7:"default";s:7:"exclude";i:0;}}',
-        'description' => '',
-        'widget_module' => 'text',
-        'widget_active' => 1,
-      ),
-      'content_node_field' => array(
-        'field_name' => 'field_test_two',
-        'type' => 'text',
-        'global_settings' => 'a:4:{s:15:"text_processing";s:1:"0";s:10:"max_length";s:0:"";s:14:"allowed_values";s:0:"";s:18:"allowed_values_php";s:0:"";}',
-        'required' => 0,
-        'multiple' => 1,
-        'db_storage' => 0,
-        'module' => 'text',
-        'db_columns' => 'a:1:{s:5:"value";a:5:{s:4:"type";s:4:"text";s:4:"size";s:3:"big";s:8:"not null";b:0;s:8:"sortable";b:1;s:5:"views";b:1;}}',
-        'active' => 1,
-        'locked' => 0,
-      ),
-
-      // Multi field values.
-      'values' => array(
-        array(
-          'vid' => 1,
-          'nid' => 1,
-          'field_test_two_value' => 'test field node 1, value 1',
-          'delta' => 0,
-        ),
-        array(
-          'vid' => 1,
-          'nid' => 1,
-          'field_test_two_value' => 'test field node 1, value 2',
-          'delta' => 1,
-        ),
-        array(
-          'vid' => 3,
-          'nid' => 1,
-          'field_test_two_value' => 'test field node 1, value 1',
-          'delta' => 0,
-        ),
-        array(
-          'vid' => 3,
-          'nid' => 1,
-          'field_test_two_value' => 'test field node 1, value 2',
-          'delta' => 1,
-        ),
-        array(
-          'vid' => 4,
-          'nid' => 1,
-          'field_test_two_value' => 'test field node 1, value 1',
-          'delta' => 0,
-        ),
-        array(
-          'vid' => 4,
-          'nid' => 1,
-          'field_test_two_value' => 'test field node 1, value 2',
-          'delta' => 1,
-        ),
-        array(
-          'vid' => 2,
-          'nid' => 2,
-          'field_test_two_value' => 'test field node 2',
-          'delta' => 0,
-        ),
-      ),
-    ),
-  );
-
-  /**
-   * {@inheritdoc}
-   */
-  public static function getInfo() {
-    return array(
-      'name' => 'D6 node revision source functionality',
-      'description' => 'Tests D6 node revision source plugin.',
-      'group' => 'Migrate Drupal',
-    );
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  protected function setUp() {
-    foreach ($this->expectedResults as $k => $row) {
-      $this->databaseContents['node_revisions'][$k]['nid'] = $row['nid'];
-      $this->databaseContents['node_revisions'][$k]['vid'] = $row['vid'];
-      $this->databaseContents['node_revisions'][$k]['uid'] = $row['uid'];
-      $this->databaseContents['node_revisions'][$k]['title'] = $row['title'];
-      $this->databaseContents['node_revisions'][$k]['body'] = $row['body'];
-      $this->databaseContents['node_revisions'][$k]['teaser'] = $row['teaser'];
-      $this->databaseContents['node_revisions'][$k]['format'] = $row['format'];
-      $this->databaseContents['node_revisions'][$k]['log'] = $row['log'];
-
-      unset($row['body']);
-      unset($row['teaser']);
-      unset($row['format']);
-      unset($row['log']);
-
-      //$this->databaseContents['node'][$k] = $row;
-      $this->databaseContents['node'][$row['nid']] = $row;
-
-      // Add the column field storage data.
-      $table = 'content_type_' . $row['type'];
-      foreach ($row['fields'] as $field_name => $value) {
-        $this->databaseContents[$table][$k][$field_name . "_value"] = $value;
-        $this->databaseContents[$table][$k]['vid'] = $row['vid'];
-        $this->databaseContents[$table][$k]['nid'] = $row['nid'];
-      }
-      // Unset from results.
-      unset($row['fields']);
-      unset($this->expectedResults[$k]['fields']);
-    }
-
-    // Setup field tables.
-    foreach ($this->fields as $field) {
-      $cnf = $field['content_node_field'];
-      $this->databaseContents['content_node_field'][] = $cnf;
-      $this->databaseContents['content_node_field_instance'][] = $field['content_node_field_instance'];
-
-      // If it's a multi-field then setup a new table.
-      if ($cnf['multiple']) {
-        foreach ($field['values'] as $value) {
-          $this->databaseContents['content_' . $cnf['field_name']][] = $value;
-        }
-      }
-    }
-
-    parent::setUp();
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function testRetrieval() {
-    // FakeSelect does not support multiple source identifiers, can not test.
-  }
-
-}
-
-namespace Drupal\migrate_drupal\Tests\source\d6;
-
-use Drupal\Core\Database\Connection;
-use Drupal\Core\Extension\ModuleHandlerInterface;
-use Drupal\migrate_drupal\Plugin\migrate\source\d6\NodeRevision;
-
-class TestNodeRevision extends NodeRevision {
-  public function setDatabase(Connection $database) {
-    $this->database = $database;
-  }
-  public function setModuleHandler(ModuleHandlerInterface $module_handler) {
-    $this->moduleHandler = $module_handler;
-  }
-}
diff --git a/core/tests/Drupal/Tests/Core/Entity/ContentEntityBaseUnitTest.php b/core/tests/Drupal/Tests/Core/Entity/ContentEntityBaseUnitTest.php
index 08fa85c..065656e 100644
--- a/core/tests/Drupal/Tests/Core/Entity/ContentEntityBaseUnitTest.php
+++ b/core/tests/Drupal/Tests/Core/Entity/ContentEntityBaseUnitTest.php
@@ -17,6 +17,7 @@
  * @coversDefaultClass \Drupal\Core\Entity\ContentEntityBase
  *
  * @group Drupal
+ * @group Entity
  */
 class ContentEntityBaseUnitTest extends UnitTestCase {
 
@@ -276,7 +277,10 @@ public function testPreSaveRevision() {
     // This method is internal, so check for errors on calling it only.
     $storage = $this->getMock('\Drupal\Core\Entity\EntityStorageInterface');
     $record = new \stdClass();
-    $this->entity->preSaveRevision($storage, $record);
+    // Our mocked preSaveRevision() returns NULL.
+    $this->assertNull(
+      $this->entity->preSaveRevision($storage, $record)
+    );
   }
 
   /**
@@ -364,7 +368,10 @@ public function testGetParent() {
   public function testSetContext() {
     $name = $this->randomName();
     $parent = $this->getMock('\Drupal\Core\TypedData\TypedDataInterface');
-    $this->entity->setContext($name, $parent);
+    // Our mocked setContext() returns NULL.
+    $this->assertNull(
+      $this->entity->setContext($name, $parent)
+    );
   }
 
   /**
diff --git a/core/tests/Drupal/Tests/Core/Entity/EntityResolverManagerTest.php b/core/tests/Drupal/Tests/Core/Entity/EntityResolverManagerTest.php
index 4df611c..379f211 100644
--- a/core/tests/Drupal/Tests/Core/Entity/EntityResolverManagerTest.php
+++ b/core/tests/Drupal/Tests/Core/Entity/EntityResolverManagerTest.php
@@ -75,7 +75,6 @@ public static function getInfo() {
    * {@inheritdoc}
    *
    * @covers ::__construct()
-   * @covers ::setContainer()
    */
   protected function setUp() {
     $this->entityManager = $this->getMock('Drupal\Core\Entity\EntityManagerInterface');
diff --git a/core/tests/Drupal/Tests/Core/Entity/EntityUnitTest.php b/core/tests/Drupal/Tests/Core/Entity/EntityUnitTest.php
index 3ecc8de..6448f69 100644
--- a/core/tests/Drupal/Tests/Core/Entity/EntityUnitTest.php
+++ b/core/tests/Drupal/Tests/Core/Entity/EntityUnitTest.php
@@ -18,6 +18,7 @@
  * @coversDefaultClass \Drupal\Core\Entity\Entity
  *
  * @group Drupal
+ * @group Entity
  */
 class EntityUnitTest extends UnitTestCase {
 
@@ -542,7 +543,10 @@ public function testGetEntityTypeId() {
   public function testPreSave() {
     // This method is internal, so check for errors on calling it only.
     $storage = $this->getMock('\Drupal\Core\Entity\EntityStorageInterface');
-    $this->entity->preSave($storage);
+    // Our mocked preSave() returns NULL.
+    $this->assertNull(
+      $this->entity->preSave($storage)
+    );
   }
 
   /**
@@ -578,7 +582,10 @@ public function testPreCreate() {
     // This method is internal, so check for errors on calling it only.
     $storage = $this->getMock('\Drupal\Core\Entity\EntityStorageInterface');
     $values = array();
-    $this->entity->preCreate($storage, $values);
+    // Our mocked preCreate() returns NULL.
+    $this->assertNull(
+      $this->entity->preCreate($storage, $values)
+    );
   }
 
   /**
@@ -587,7 +594,10 @@ public function testPreCreate() {
   public function testPostCreate() {
     // This method is internal, so check for errors on calling it only.
     $storage = $this->getMock('\Drupal\Core\Entity\EntityStorageInterface');
-    $this->entity->postCreate($storage);
+    // Our mocked postCreate() returns NULL.
+    $this->assertNull(
+      $this->entity->postCreate($storage)
+    );
   }
 
   /**
@@ -596,7 +606,10 @@ public function testPostCreate() {
   public function testPreDelete() {
     // This method is internal, so check for errors on calling it only.
     $storage = $this->getMock('\Drupal\Core\Entity\EntityStorageInterface');
-    $this->entity->preDelete($storage, array($this->entity));
+    // Our mocked preDelete() returns NULL.
+    $this->assertNull(
+      $this->entity->preDelete($storage, array($this->entity))
+    );
   }
 
   /**
@@ -629,7 +642,10 @@ public function testPostLoad() {
     // This method is internal, so check for errors on calling it only.
     $storage = $this->getMock('\Drupal\Core\Entity\EntityStorageInterface');
     $entities = array($this->entity);
-    $this->entity->postLoad($storage, $entities);
+    // Our mocked postLoad() returns NULL.
+    $this->assertNull(
+      $this->entity->postLoad($storage, $entities)
+    );
   }
 
   /**
diff --git a/core/tests/Drupal/Tests/Core/EventSubscriber/AccessSubscriberTest.php b/core/tests/Drupal/Tests/Core/EventSubscriber/AccessSubscriberTest.php
index 5ec7f81..746b5c8 100644
--- a/core/tests/Drupal/Tests/Core/EventSubscriber/AccessSubscriberTest.php
+++ b/core/tests/Drupal/Tests/Core/EventSubscriber/AccessSubscriberTest.php
@@ -26,6 +26,7 @@
  *
  * @group System
  * @group Drupal
+ * @group EventSubscriber
  */
 class AccessSubscriberTest extends UnitTestCase {
 
@@ -166,6 +167,7 @@ public function testAccessSubscriberDoesNotAlterRequestIfAccessManagerGrantsAcce
       ->will($this->returnValue(TRUE));
 
     $subscriber = new AccessSubscriber($this->accessManager, $this->currentUser);
+    // The onKernelRequestAccessCheck() method has no return value.
     $subscriber->onKernelRequestAccessCheck($this->event);
   }
 
diff --git a/core/tests/Drupal/Tests/Core/EventSubscriber/ModuleRouteSubscriberTest.php b/core/tests/Drupal/Tests/Core/EventSubscriber/ModuleRouteSubscriberTest.php
index 0018ffd..e29c0da 100644
--- a/core/tests/Drupal/Tests/Core/EventSubscriber/ModuleRouteSubscriberTest.php
+++ b/core/tests/Drupal/Tests/Core/EventSubscriber/ModuleRouteSubscriberTest.php
@@ -16,9 +16,11 @@
 /**
  * Tests the ModuleRouteSubscriber class.
  *
- * @group Drupal
- *
  * @see \Drupal\Core\EventSubscriber\ModuleRouteSubscriber
+ *
+ * @coversDefaultClass \Drupal\Core\EventSubscriber\ModuleRouteSubscriber
+ * @group Drupal
+ * @group EventSubscriber
  */
 class ModuleRouteSubscriberTest extends UnitTestCase {
 
@@ -53,7 +55,8 @@ public function setUp() {
   /**
    * Tests that removeRoute() removes routes when the module is not enabled.
    *
-   * @dataProvider testRemoveRouteProvider
+   * @dataProvider providerTestRemoveRoute
+   * @covers ::onAlterRoutes()
    *
    * @param string $route_name
    *   The machine name for the route.
@@ -82,7 +85,7 @@ public function testRemoveRoute($route_name, array $requirements, $removed) {
   /**
    * Data provider for testRemoveRoute().
    */
-  public function testRemoveRouteProvider() {
+  public function providerTestRemoveRoute() {
     return array(
       array('enabled', array('_module_dependencies' => 'enabled'), FALSE),
       array('disabled', array('_module_dependencies' => 'disabled'), TRUE),
diff --git a/core/tests/Drupal/Tests/Core/Image/ImageTest.php b/core/tests/Drupal/Tests/Core/Image/ImageTest.php
index 8e1fd65..766d2fc 100644
--- a/core/tests/Drupal/Tests/Core/Image/ImageTest.php
+++ b/core/tests/Drupal/Tests/Core/Image/ImageTest.php
@@ -12,6 +12,10 @@
 
 /**
  * Tests the image class.
+ *
+ * @requires extension gd
+ * @group Drupal
+ * @group Image
  */
 class ImageTest extends UnitTestCase {