diff --git a/core/modules/comment/lib/Drupal/comment/Routing/CommentBundleEnhancer.php b/core/modules/comment/lib/Drupal/comment/Routing/CommentBundleEnhancer.php
index bc0ed8c..025e6ca 100644
--- a/core/modules/comment/lib/Drupal/comment/Routing/CommentBundleEnhancer.php
+++ b/core/modules/comment/lib/Drupal/comment/Routing/CommentBundleEnhancer.php
@@ -30,6 +30,9 @@ class CommentBundleEnhancer implements RouteEnhancerInterface {
 
   /**
    * Constructs a CommentBundleEnhancer object.
+   *
+   * @param \Drupal\Core\Entity\EntityManager $entity_manager
+   *   The entity manager service.
    */
   public function __construct(EntityManager $entity_manager) {
     $this->entityManager = $entity_manager;
diff --git a/core/modules/comment/tests/Drupal/comment/Tests/Routing/CommentBundleEnhancerTest.php b/core/modules/comment/tests/Drupal/comment/Tests/Routing/CommentBundleEnhancerTest.php
index 9511cdb..d86d1ba 100644
--- a/core/modules/comment/tests/Drupal/comment/Tests/Routing/CommentBundleEnhancerTest.php
+++ b/core/modules/comment/tests/Drupal/comment/Tests/Routing/CommentBundleEnhancerTest.php
@@ -21,16 +21,55 @@ public static function getInfo() {
     return array(
       'name' => 'Comment route enhancer test',
       'description' => 'Tests the comment route enhancer.',
-      'group' => 'Comment'
+      'group' => 'Comment',
     );
   }
 
   /**
+   * Data provider for testEnhancer().
+   *
+   * @see testEnhancer()
+   *
+   * @return array
+   *   An array of arrays containing strings:
+   *     - The bundle name.
+   *     - The commented entity type.
+   *     - The field name.
+   */
+  public function providerTestEnhancer() {
+    return array(
+      array(
+        'node__comment',
+        'comment',
+        'node',
+      ),
+      array(
+        'node__comment_forum__schnitzel',
+        'comment_forum__schnitzel',
+        'node',
+      ),
+      array(
+        'node__field_foobar',
+        FALSE,
+        FALSE
+      ),
+    );
+  }
+  /**
    * Tests the enhancer method.
    *
+   * @param string $bundle
+   *   The bundle name to test.
+   * @param string $field_name
+   *   The field name expected to be extracted from the bundle.
+   * @param string $commented_entity_type
+   *   The entity type expected to be extracted from the bundle.
+   *
    * @see \Drupal\comment\Routing\CommentBundleEnhancer::enhancer()
+   *
+   * @dataProvider providerTestEnhancer
    */
-  public function testEnhancer() {
+  public function testEnhancer($bundle, $field_name, $commented_entity_type) {
     $entityManager = $this->getMockBuilder('\Drupal\Core\Entity\EntityManager')
       ->disableOriginalConstructor()
       ->getMock();
@@ -38,23 +77,25 @@ public function testEnhancer() {
       ->method('getBundleInfo')
       ->will($this->returnValue(array(
         'node__comment' => array(),
-        'node__comment_forum' => array(),
+        // Test two sets of __.
+        'node__comment_forum__schnitzel' => array(),
       )));
     $route_enhancer = new CommentBundleEnhancer($entityManager);
 
-    // Test with a comment bundle.
-    $request = new Request();
-    $defaults = array('bundle' => 'node__comment');
-    $new_defaults = $route_enhancer->enhance($defaults, $request);
-    $this->assertEquals($new_defaults['field_name'], 'comment');
-    $this->assertEquals($new_defaults['commented_entity_type'], 'node');
-
-    // Test again with a non-comment bundle
+    // Test the enhancer.
     $request = new Request();
-    $defaults = array('bundle' => 'node__field_foobar');
+    $defaults = array('bundle' => $bundle);
     $new_defaults = $route_enhancer->enhance($defaults, $request);
-    $this->assertTrue(empty($new_defaults['field_name']));
-    $this->assertTrue(empty($new_defaults['commented_entity_type']));
+    if ($commented_entity_type) {
+      // A valid comment bundle.
+      $this->assertEquals($new_defaults['field_name'], $field_name);
+      $this->assertEquals($new_defaults['commented_entity_type'], $commented_entity_type);
+    }
+    else {
+      // Non-comment bundle.
+      $this->assertTrue(empty($new_defaults['field_name']));
+      $this->assertTrue(empty($new_defaults['commented_entity_type']));
+    }
   }
 
 }