diff --git a/core/lib/Drupal/Core/Plugin/DefaultPluginManager.php b/core/lib/Drupal/Core/Plugin/DefaultPluginManager.php
index f61839e..4e28c53 100644
--- a/core/lib/Drupal/Core/Plugin/DefaultPluginManager.php
+++ b/core/lib/Drupal/Core/Plugin/DefaultPluginManager.php
@@ -120,13 +120,12 @@ class DefaultPluginManager extends PluginManagerBase implements PluginManagerInt
    *   (optional) The name of the annotation that contains the plugin definition.
    *   Defaults to 'Drupal\Component\Annotation\Plugin'.
    */
-  public function __construct($subdir, \Traversable $namespaces, ModuleHandlerInterface $module_handler, $plugin_definition_annotation_name = 'Drupal\Component\Annotation\Plugin', $fallback_plugin_id = NULL) {
+  public function __construct($subdir, \Traversable $namespaces, ModuleHandlerInterface $module_handler, $plugin_definition_annotation_name = 'Drupal\Component\Annotation\Plugin') {
     $this->subdir = $subdir;
     $this->discovery = new AnnotatedClassDiscovery($subdir, $namespaces, $plugin_definition_annotation_name);
     $this->discovery = new ContainerDerivativeDiscoveryDecorator($this->discovery);
     $this->factory = new ContainerFactory($this);
     $this->moduleHandler = $module_handler;
-    $this->fallbackPluginId = $fallback_plugin_id;
   }
 
   /**
@@ -171,6 +170,16 @@ protected function alterInfo($alter_hook) {
   }
 
   /**
+   * Sets the fallback plugin ID.
+   *
+   * @param string $fallback_plugin_id
+   *   The plugin ID to be falled back to.
+   */
+  public function setFallbackPluginId($fallback_plugin_id) {
+    $this->fallbackPluginId = $fallback_plugin_id;
+  }
+
+  /**
    * {@inheritdoc}
    */
   public function getDefinition($plugin_id) {
@@ -291,7 +300,6 @@ protected function findDefinitions() {
    * {@inheritdoc}
    */
   public function createInstance($plugin_id, array $configuration = array()) {
-
     try {
       $instance = $this->factory->createInstance($plugin_id, $configuration);
     }
@@ -319,7 +327,7 @@ public function createInstance($plugin_id, array $configuration = array()) {
    * @return string
    *   The plugin ID of the fallback instance.
    */
-  protected function getFallbackPluginId($original_plugin_id, $configuration) {
+  protected function getFallbackPluginId($original_plugin_id, array $configuration) {
     return $this->fallbackPluginId;
   }
 
diff --git a/core/tests/Drupal/Tests/Core/Plugin/DefaultPluginManagerTest.php b/core/tests/Drupal/Tests/Core/Plugin/DefaultPluginManagerTest.php
index 5c0d888..7bb996e 100644
--- a/core/tests/Drupal/Tests/Core/Plugin/DefaultPluginManagerTest.php
+++ b/core/tests/Drupal/Tests/Core/Plugin/DefaultPluginManagerTest.php
@@ -17,6 +17,9 @@
  * Tests the DefaultPluginManager.
  *
  * @group Plugin
+ * @group Drupal
+ *
+ * @coversDefaultClass Drupal\Core\Plugin\DefaultPluginManager
  */
 class DefaultPluginManagerTest extends UnitTestCase {
 
@@ -72,6 +75,8 @@ protected function setUp() {
 
   /**
    * Tests the plugin manager with a disabled module.
+   *
+   * @covers ::getDefinition
    */
   public function testDefaultPluginManagerWithDisabledModule() {
      $definitions = $this->expectedDefinitions;
@@ -97,6 +102,9 @@ public function testDefaultPluginManagerWithDisabledModule() {
 
   /**
    * Tests the plugin manager with no cache and altering.
+   *
+   * @covers ::getDefinitions
+   * @covers ::getDefinition
    */
   public function testDefaultPluginManager() {
     $plugin_manager = new TestPluginManager($this->namespaces, $this->expectedDefinitions);
@@ -106,6 +114,9 @@ public function testDefaultPluginManager() {
 
   /**
    * Tests the plugin manager with no cache and altering.
+   *
+   * @covers ::getDefinitions
+   * @covers ::getDefinition
    */
   public function testDefaultPluginManagerWithAlter() {
     $module_handler = $this->getMock('Drupal\Core\Extension\ModuleHandler');
@@ -124,6 +135,9 @@ public function testDefaultPluginManagerWithAlter() {
 
   /**
    * Tests the plugin manager with caching and altering.
+   *
+   * @covers ::getDefinitions
+   * @covers ::getDefinition
    */
   public function testDefaultPluginManagerWithEmptyCache() {
     $cid = $this->randomName();
@@ -156,6 +170,8 @@ public function testDefaultPluginManagerWithEmptyCache() {
 
   /**
    * Tests the plugin manager with caching and altering.
+   *
+   * @covers ::getDefinitions
    */
   public function testDefaultPluginManagerWithFilledCache() {
     $cid = $this->randomName();
@@ -186,6 +202,9 @@ public function testDefaultPluginManagerWithFilledCache() {
 
   /**
    * Tests the plugin manager cache clear with tags.
+   *
+   * @covers ::getFallbackPluginId
+   * @covers ::createInstance
    */
   public function testCacheClearWithTags() {
     $cid = $this->randomName();
@@ -241,16 +260,17 @@ public function testCreateInstanceWithFallback() {
     $exception = new PluginException();
     $factory->expects($this->at(0))
       ->method('createInstance')
-      ->with('non_existing', array())
+      ->with('non_existing', array('key' => 'value'))
       ->will($this->throwException($exception));
     $factory->expects($this->at(1))
       ->method('createInstance')
-      ->with('apple', array('_exception' => $exception))
+      ->with('apple', array('_exception' => $exception, 'key' => 'value'))
       ->will($this->returnValue($apple));
 
-    $plugin_manager = new TestPluginManager($this->namespaces, $this->expectedDefinitions, NULL, NULL, 'apple');
+    $plugin_manager = new TestPluginManager($this->namespaces, $this->expectedDefinitions);
+    $plugin_manager->setFallbackPluginId('apple');
     $plugin_manager->setFactory($factory);
-    $plugin = $plugin_manager->createInstance('non_existing');
+    $plugin = $plugin_manager->createInstance('non_existing', array('key' => 'value'));
     $this->assertSame($apple, $plugin);
   }
 
diff --git a/core/tests/Drupal/Tests/Core/Plugin/TestPluginManager.php b/core/tests/Drupal/Tests/Core/Plugin/TestPluginManager.php
index e977b6e..4619640 100644
--- a/core/tests/Drupal/Tests/Core/Plugin/TestPluginManager.php
+++ b/core/tests/Drupal/Tests/Core/Plugin/TestPluginManager.php
@@ -32,7 +32,7 @@ class TestPluginManager extends DefaultPluginManager {
    * @param string $fallback_plugin_id
    *   (optional) The fallback plugin ID.
    */
-  public function __construct(\Traversable $namespaces, array $definitions, ModuleHandlerInterface $module_handler = NULL, $alter_hook = NULL, $fallback_plugin_id = NULL) {
+  public function __construct(\Traversable $namespaces, array $definitions, ModuleHandlerInterface $module_handler = NULL, $alter_hook = NULL) {
     // Create the object that can be used to return definitions for all the
     // plugins available for this type. Most real plugin managers use a richer
     // discovery implementation, but StaticDiscovery lets us add some simple
@@ -49,8 +49,6 @@ public function __construct(\Traversable $namespaces, array $definitions, Module
     if ($alter_hook) {
       $this->alterInfo($alter_hook);
     }
-
-    $this->fallbackPluginId = $fallback_plugin_id;
   }
 
   /**