diff --git a/core/modules/comment/comment.test b/core/modules/comment/comment.test
index 2e0a2098a25e892d22562fb5a1e0723093940ff4..a791b2d599dce5d9e1cbc3bfeedb1cb0e6f1513c 100644
--- a/core/modules/comment/comment.test
+++ b/core/modules/comment/comment.test
@@ -6,269 +6,10 @@
  */
 
 use Drupal\comment\Comment;
+use Drupal\comment\Tests\CommentTestBase;
 use Drupal\simpletest\WebTestBase;
 
-class CommentHelperCase extends WebTestBase {
-  protected $profile = 'standard';
-
-  protected $admin_user;
-  protected $web_user;
-  protected $node;
-
-  function setUp() {
-    parent::setUp('comment', 'search');
-    // Create users and test node.
-    $this->admin_user = $this->drupalCreateUser(array('administer content types', 'administer comments', 'administer blocks'));
-    $this->web_user = $this->drupalCreateUser(array('access comments', 'post comments', 'create article content', 'edit own comments'));
-    $this->node = $this->drupalCreateNode(array('type' => 'article', 'promote' => 1, 'uid' => $this->web_user->uid));
-  }
-
-  /**
-   * Posts a comment.
-   *
-   * @param Node|NULL $node
-   *   Node to post comment on or NULL to post to the previusly loaded page.
-   * @param $comment
-   *   Comment body.
-   * @param $subject
-   *   Comment subject.
-   * @param $contact
-   *   Set to NULL for no contact info, TRUE to ignore success checking, and
-   *   array of values to set contact info.
-   */
-  function postComment($node, $comment, $subject = '', $contact = NULL) {
-    $langcode = LANGUAGE_NOT_SPECIFIED;
-    $edit = array();
-    $edit['comment_body[' . $langcode . '][0][value]'] = $comment;
-
-    $preview_mode = variable_get('comment_preview_article', DRUPAL_OPTIONAL);
-    $subject_mode = variable_get('comment_subject_field_article', 1);
-
-    // Must get the page before we test for fields.
-    if ($node !== NULL) {
-      $this->drupalGet('comment/reply/' . $node->nid);
-    }
-
-    if ($subject_mode == TRUE) {
-      $edit['subject'] = $subject;
-    }
-    else {
-      $this->assertNoFieldByName('subject', '', t('Subject field not found.'));
-    }
-
-    if ($contact !== NULL && is_array($contact)) {
-      $edit += $contact;
-    }
-    switch ($preview_mode) {
-      case DRUPAL_REQUIRED:
-        // Preview required so no save button should be found.
-        $this->assertNoFieldByName('op', t('Save'), t('Save button not found.'));
-        $this->drupalPost(NULL, $edit, t('Preview'));
-        // Don't break here so that we can test post-preview field presence and
-        // function below.
-      case DRUPAL_OPTIONAL:
-        $this->assertFieldByName('op', t('Preview'), t('Preview button found.'));
-        $this->assertFieldByName('op', t('Save'), t('Save button found.'));
-        $this->drupalPost(NULL, $edit, t('Save'));
-        break;
-
-      case DRUPAL_DISABLED:
-        $this->assertNoFieldByName('op', t('Preview'), t('Preview button not found.'));
-        $this->assertFieldByName('op', t('Save'), t('Save button found.'));
-        $this->drupalPost(NULL, $edit, t('Save'));
-        break;
-    }
-    $match = array();
-    // Get comment ID
-    preg_match('/#comment-([0-9]+)/', $this->getURL(), $match);
-
-    // Get comment.
-    if ($contact !== TRUE) { // If true then attempting to find error message.
-      if ($subject) {
-        $this->assertText($subject, 'Comment subject posted.');
-      }
-      $this->assertText($comment, 'Comment body posted.');
-      $this->assertTrue((!empty($match) && !empty($match[1])), t('Comment id found.'));
-    }
-
-    if (isset($match[1])) {
-      return entity_create('comment', array('id' => $match[1], 'subject' => $subject, 'comment' => $comment));
-    }
-  }
-
-  /**
-   * Checks current page for specified comment.
-   *
-   * @param Drupal\comment\Comment $comment
-   *   The comment object.
-   * @param boolean $reply
-   *   Boolean indicating whether the comment is a reply to another comment.
-   *
-   * @return boolean
-   *   Boolean indicating whether the comment was found.
-   */
-  function commentExists(Comment $comment = NULL, $reply = FALSE) {
-    if ($comment) {
-      $regex = '/' . ($reply ? '<div class="indented">(.*?)' : '');
-      $regex .= '<a id="comment-' . $comment->id . '"(.*?)'; // Comment anchor.
-      $regex .= '<div(.*?)'; // Begin in comment div.
-      $regex .= $comment->subject . '(.*?)'; // Match subject.
-      $regex .= $comment->comment . '(.*?)'; // Match comment.
-      $regex .= '/s';
-
-      return (boolean)preg_match($regex, $this->drupalGetContent());
-    }
-    else {
-      return FALSE;
-    }
-  }
-
-  /**
-   * Deletes a comment.
-   *
-   * @param Drupal\comment\Comment $comment
-   *   Comment to delete.
-   */
-  function deleteComment(Comment $comment) {
-    $this->drupalPost('comment/' . $comment->id . '/delete', array(), t('Delete'));
-    $this->assertText(t('The comment and all its replies have been deleted.'), t('Comment deleted.'));
-  }
-
-  /**
-   * Sets the value governing whether the subject field should be enabled.
-   *
-   * @param boolean $enabled
-   *   Boolean specifying whether the subject field should be enabled.
-   */
-  function setCommentSubject($enabled) {
-    $this->setCommentSettings('comment_subject_field', ($enabled ? '1' : '0'), 'Comment subject ' . ($enabled ? 'enabled' : 'disabled') . '.');
-  }
-
-  /**
-   * Sets the value governing the previewing mode for the comment form.
-   *
-   * @param int $mode
-   *   The preview mode: DRUPAL_DISABLED, DRUPAL_OPTIONAL or DRUPAL_REQUIRED.
-   */
-  function setCommentPreview($mode) {
-    switch ($mode) {
-      case DRUPAL_DISABLED:
-        $mode_text = 'disabled';
-        break;
-
-      case DRUPAL_OPTIONAL:
-        $mode_text = 'optional';
-        break;
-
-      case DRUPAL_REQUIRED:
-        $mode_text = 'required';
-        break;
-    }
-    $this->setCommentSettings('comment_preview', $mode, 'Comment preview ' . $mode_text . '.');
-  }
-
-  /**
-   * Sets the value governing whether the comment form is on its own page.
-   *
-   * @param boolean $enabled
-   *   TRUE if the comment form should be displayed on the same page as the
-   *   comments; FALSE if it should be displayed on its own page.
-   */
-  function setCommentForm($enabled) {
-    $this->setCommentSettings('comment_form_location', ($enabled ? COMMENT_FORM_BELOW : COMMENT_FORM_SEPARATE_PAGE), 'Comment controls ' . ($enabled ? 'enabled' : 'disabled') . '.');
-  }
-
-  /**
-   * Sets the value governing restrictions on anonymous comments.
-   *
-   * @param integer $level
-   *   The level of the contact information allowed for anonymous comments:
-   *   - 0: No contact information allowed.
-   *   - 1: Contact information allowed but not required.
-   *   - 2: Contact information required.
-   */
-  function setCommentAnonymous($level) {
-    $this->setCommentSettings('comment_anonymous', $level, 'Anonymous commenting set to level ' . $level . '.');
-  }
-
-  /**
-   * Sets the value specifying the default number of comments per page.
-   *
-   * @param integer $comments
-   *   Comments per page value.
-   */
-  function setCommentsPerPage($number) {
-    $this->setCommentSettings('comment_default_per_page', $number, 'Number of comments per page set to ' . $number . '.');
-  }
-
-  /**
-   * Sets a comment settings variable for the article content type.
-   *
-   * @param string $name
-   *   Name of variable.
-   * @param string $value
-   *   Value of variable.
-   * @param string $message
-   *   Status message to display.
-   */
-  function setCommentSettings($name, $value, $message) {
-    variable_set($name . '_article', $value);
-    $this->assertTrue(TRUE, t($message)); // Display status message.
-  }
-
-  /**
-   * Checks whether the commenter's contact information is displayed.
-   *
-   * @return boolean
-   *   Contact info is available.
-   */
-  function commentContactInfoAvailable() {
-    return preg_match('/(input).*?(name="name").*?(input).*?(name="mail").*?(input).*?(name="homepage")/s', $this->drupalGetContent());
-  }
-
-  /**
-   * Performs the specified operation on the specified comment.
-   *
-   * @param object $comment
-   *   Comment to perform operation on.
-   * @param string $operation
-   *   Operation to perform.
-   * @param boolean $aproval
-   *   Operation is found on approval page.
-   */
-  function performCommentOperation($comment, $operation, $approval = FALSE) {
-    $edit = array();
-    $edit['operation'] = $operation;
-    $edit['comments[' . $comment->id . ']'] = TRUE;
-    $this->drupalPost('admin/content/comment' . ($approval ? '/approval' : ''), $edit, t('Update'));
-
-    if ($operation == 'delete') {
-      $this->drupalPost(NULL, array(), t('Delete comments'));
-      $this->assertRaw(format_plural(1, 'Deleted 1 comment.', 'Deleted @count comments.'), t('Operation "' . $operation . '" was performed on comment.'));
-    }
-    else {
-      $this->assertText(t('The update has been performed.'), t('Operation "' . $operation . '" was performed on comment.'));
-    }
-  }
-
-  /**
-   * Gets the comment ID for an unapproved comment.
-   *
-   * @param string $subject
-   *   Comment subject to find.
-   *
-   * @return integer
-   *   Comment id.
-   */
-  function getUnapprovedComment($subject) {
-    $this->drupalGet('admin/content/comment/approval');
-    preg_match('/href="(.*?)#comment-([^"]+)"(.*?)>(' . $subject . ')/', $this->drupalGetContent(), $match);
-
-    return $match[2];
-  }
-}
-
-class CommentInterfaceTest extends CommentHelperCase {
+class CommentInterfaceTest extends CommentTestBase {
   public static function getInfo() {
     return array(
       'name' => 'Comment interface',
@@ -959,7 +700,7 @@ class CommentInterfaceTest extends CommentHelperCase {
 /**
  * Tests previewing comments.
  */
-class CommentPreviewTest extends CommentHelperCase {
+class CommentPreviewTest extends CommentTestBase {
   public static function getInfo() {
     return array(
       'name' => 'Comment preview',
@@ -1083,7 +824,7 @@ class CommentPreviewTest extends CommentHelperCase {
 /**
  * Tests anonymous commenting.
  */
-class CommentAnonymous extends CommentHelperCase {
+class CommentAnonymous extends CommentTestBase {
   public static function getInfo() {
     return array(
       'name' => 'Anonymous comments',
@@ -1236,7 +977,7 @@ class CommentAnonymous extends CommentHelperCase {
 /**
  * Verifies pagination of comments.
  */
-class CommentPagerTest extends CommentHelperCase {
+class CommentPagerTest extends CommentTestBase {
 
   public static function getInfo() {
     return array(
@@ -1506,7 +1247,7 @@ class CommentPagerTest extends CommentHelperCase {
  * viewing a node with threaded comments (a comment and a reply), if a node
  * access module is in use.
  */
-class CommentNodeAccessTest extends CommentHelperCase {
+class CommentNodeAccessTest extends CommentTestBase {
   public static function getInfo() {
     return array(
       'name' => 'Comment node access',
@@ -1570,7 +1311,7 @@ class CommentNodeAccessTest extends CommentHelperCase {
 /**
  * Tests comment approval functionality.
  */
-class CommentApprovalTest extends CommentHelperCase {
+class CommentApprovalTest extends CommentTestBase {
   public static function getInfo() {
     return array(
       'name' => 'Comment approval',
@@ -1694,7 +1435,7 @@ class CommentApprovalTest extends CommentHelperCase {
 /**
  * Tests the Comment module blocks.
  */
-class CommentBlockFunctionalTest extends CommentHelperCase {
+class CommentBlockFunctionalTest extends CommentTestBase {
   public static function getInfo() {
     return array(
       'name' => 'Comment blocks',
@@ -1789,7 +1530,7 @@ class CommentBlockFunctionalTest extends CommentHelperCase {
 /**
  * Unit tests for Comment module integration with RSS feeds.
  */
-class CommentRSSUnitTest extends CommentHelperCase {
+class CommentRSSUnitTest extends CommentTestBase {
   public static function getInfo() {
     return array(
       'name' => 'Comment RSS',
@@ -1821,7 +1562,7 @@ class CommentRSSUnitTest extends CommentHelperCase {
 /**
  * Tests comment content rebuilding.
  */
-class CommentContentRebuild extends CommentHelperCase {
+class CommentContentRebuild extends CommentTestBase {
   public static function getInfo() {
     return array(
       'name' => 'Comment Rebuild',
@@ -1860,7 +1601,7 @@ class CommentContentRebuild extends CommentHelperCase {
 /**
  * Tests comment token replacement in strings.
  */
-class CommentTokenReplaceTestCase extends CommentHelperCase {
+class CommentTokenReplaceTestCase extends CommentTestBase {
   public static function getInfo() {
     return array(
       'name' => 'Comment token replacement',
@@ -1960,7 +1701,7 @@ class CommentTokenReplaceTestCase extends CommentHelperCase {
 /**
  * Tests actions provided by the Comment module.
  */
-class CommentActionsTestCase extends CommentHelperCase {
+class CommentActionsTestCase extends CommentTestBase {
   public static function getInfo() {
     return array(
       'name' => 'Comment actions',
@@ -2029,7 +1770,7 @@ class CommentActionsTestCase extends CommentHelperCase {
 /**
  * Tests fields on comments.
  */
-class CommentFieldsTest extends CommentHelperCase {
+class CommentFieldsTest extends CommentTestBase {
   public static function getInfo() {
     return array(
       'name' => 'Comment fields',
@@ -2133,7 +1874,7 @@ class CommentFieldsTest extends CommentHelperCase {
 /**
  * Tests comment threading.
  */
-class CommentThreadingTestCase extends CommentHelperCase {
+class CommentThreadingTestCase extends CommentTestBase {
   public static function getInfo() {
     return array(
       'name' => 'Comment Threading',
diff --git a/core/modules/comment/lib/Drupal/comment/Tests/CommentNodeChangesTest.php b/core/modules/comment/lib/Drupal/comment/Tests/CommentNodeChangesTest.php
new file mode 100644
index 0000000000000000000000000000000000000000..b517d04f1a7347c1c140371246f42d6884044302
--- /dev/null
+++ b/core/modules/comment/lib/Drupal/comment/Tests/CommentNodeChangesTest.php
@@ -0,0 +1,33 @@
+<?php
+
+/**
+ * @file
+ * Definition of Drupal\comment\Tests\CommentNodeChangesTest.
+ */
+
+namespace Drupal\comment\Tests;
+
+/**
+ * Tests that comments behave correctly when the node is changed.
+ */
+class CommentNodeChangesTest extends CommentTestBase {
+
+  public static function getInfo() {
+    return array(
+      'name' => 'Comment deletion on node changes',
+      'description' => 'Tests that comments behave correctly when the node is changed.',
+      'group' => 'Comment',
+    );
+  }
+
+  /**
+   * Tests that comments are deleted with the node.
+   */
+  function testNodeDeletion() {
+    $this->drupalLogin($this->web_user);
+    $comment = $this->postComment($this->node, $this->randomName(), $this->randomName());
+    $this->assertTrue(comment_load($comment->id), 'The comment could be loaded.');
+    node_delete($this->node->nid);
+    $this->assertFalse(comment_load($comment->id), 'The comment could not be loaded after the node was deleted.');
+  }
+}
diff --git a/core/modules/comment/lib/Drupal/comment/Tests/CommentTestBase.php b/core/modules/comment/lib/Drupal/comment/Tests/CommentTestBase.php
new file mode 100644
index 0000000000000000000000000000000000000000..093f91bf6a5f3daa5a4556f30390a5ff48a63517
--- /dev/null
+++ b/core/modules/comment/lib/Drupal/comment/Tests/CommentTestBase.php
@@ -0,0 +1,271 @@
+<?php
+
+/**
+ * @file
+ * Definition of Drupal\comment\Tests\CommentTestBase.
+ */
+
+namespace Drupal\comment\Tests;
+
+use Drupal\comment\Comment;
+use Drupal\simpletest\WebTestBase;
+
+class CommentTestBase extends WebTestBase {
+  protected $profile = 'standard';
+
+  protected $admin_user;
+  protected $web_user;
+  protected $node;
+
+  function setUp() {
+    parent::setUp('comment', 'search');
+    // Create users and test node.
+    $this->admin_user = $this->drupalCreateUser(array('administer content types', 'administer comments', 'administer blocks'));
+    $this->web_user = $this->drupalCreateUser(array('access comments', 'post comments', 'create article content', 'edit own comments'));
+    $this->node = $this->drupalCreateNode(array('type' => 'article', 'promote' => 1, 'uid' => $this->web_user->uid));
+  }
+
+  /**
+   * Posts a comment.
+   *
+   * @param Node|NULL $node
+   *   Node to post comment on or NULL to post to the previusly loaded page.
+   * @param $comment
+   *   Comment body.
+   * @param $subject
+   *   Comment subject.
+   * @param $contact
+   *   Set to NULL for no contact info, TRUE to ignore success checking, and
+   *   array of values to set contact info.
+   */
+  function postComment($node, $comment, $subject = '', $contact = NULL) {
+    $langcode = LANGUAGE_NOT_SPECIFIED;
+    $edit = array();
+    $edit['comment_body[' . $langcode . '][0][value]'] = $comment;
+
+    $preview_mode = variable_get('comment_preview_article', DRUPAL_OPTIONAL);
+    $subject_mode = variable_get('comment_subject_field_article', 1);
+
+    // Must get the page before we test for fields.
+    if ($node !== NULL) {
+      $this->drupalGet('comment/reply/' . $node->nid);
+    }
+
+    if ($subject_mode == TRUE) {
+      $edit['subject'] = $subject;
+    }
+    else {
+      $this->assertNoFieldByName('subject', '', t('Subject field not found.'));
+    }
+
+    if ($contact !== NULL && is_array($contact)) {
+      $edit += $contact;
+    }
+    switch ($preview_mode) {
+      case DRUPAL_REQUIRED:
+        // Preview required so no save button should be found.
+        $this->assertNoFieldByName('op', t('Save'), t('Save button not found.'));
+        $this->drupalPost(NULL, $edit, t('Preview'));
+        // Don't break here so that we can test post-preview field presence and
+        // function below.
+      case DRUPAL_OPTIONAL:
+        $this->assertFieldByName('op', t('Preview'), t('Preview button found.'));
+        $this->assertFieldByName('op', t('Save'), t('Save button found.'));
+        $this->drupalPost(NULL, $edit, t('Save'));
+        break;
+
+      case DRUPAL_DISABLED:
+        $this->assertNoFieldByName('op', t('Preview'), t('Preview button not found.'));
+        $this->assertFieldByName('op', t('Save'), t('Save button found.'));
+        $this->drupalPost(NULL, $edit, t('Save'));
+        break;
+    }
+    $match = array();
+    // Get comment ID
+    preg_match('/#comment-([0-9]+)/', $this->getURL(), $match);
+
+    // Get comment.
+    if ($contact !== TRUE) { // If true then attempting to find error message.
+      if ($subject) {
+        $this->assertText($subject, 'Comment subject posted.');
+      }
+      $this->assertText($comment, 'Comment body posted.');
+      $this->assertTrue((!empty($match) && !empty($match[1])), t('Comment id found.'));
+    }
+
+    if (isset($match[1])) {
+      return entity_create('comment', array('id' => $match[1], 'subject' => $subject, 'comment' => $comment));
+    }
+  }
+
+  /**
+   * Checks current page for specified comment.
+   *
+   * @param Drupal\comment\Comment $comment
+   *   The comment object.
+   * @param boolean $reply
+   *   Boolean indicating whether the comment is a reply to another comment.
+   *
+   * @return boolean
+   *   Boolean indicating whether the comment was found.
+   */
+  function commentExists(Comment $comment = NULL, $reply = FALSE) {
+    if ($comment) {
+      $regex = '/' . ($reply ? '<div class="indented">(.*?)' : '');
+      $regex .= '<a id="comment-' . $comment->id . '"(.*?)'; // Comment anchor.
+      $regex .= '<div(.*?)'; // Begin in comment div.
+      $regex .= $comment->subject . '(.*?)'; // Match subject.
+      $regex .= $comment->comment . '(.*?)'; // Match comment.
+      $regex .= '/s';
+
+      return (boolean)preg_match($regex, $this->drupalGetContent());
+    }
+    else {
+      return FALSE;
+    }
+  }
+
+  /**
+   * Deletes a comment.
+   *
+   * @param Drupal\comment\Comment $comment
+   *   Comment to delete.
+   */
+  function deleteComment(Comment $comment) {
+    $this->drupalPost('comment/' . $comment->id . '/delete', array(), t('Delete'));
+    $this->assertText(t('The comment and all its replies have been deleted.'), t('Comment deleted.'));
+  }
+
+  /**
+   * Sets the value governing whether the subject field should be enabled.
+   *
+   * @param boolean $enabled
+   *   Boolean specifying whether the subject field should be enabled.
+   */
+  function setCommentSubject($enabled) {
+    $this->setCommentSettings('comment_subject_field', ($enabled ? '1' : '0'), 'Comment subject ' . ($enabled ? 'enabled' : 'disabled') . '.');
+  }
+
+  /**
+   * Sets the value governing the previewing mode for the comment form.
+   *
+   * @param int $mode
+   *   The preview mode: DRUPAL_DISABLED, DRUPAL_OPTIONAL or DRUPAL_REQUIRED.
+   */
+  function setCommentPreview($mode) {
+    switch ($mode) {
+      case DRUPAL_DISABLED:
+        $mode_text = 'disabled';
+        break;
+
+      case DRUPAL_OPTIONAL:
+        $mode_text = 'optional';
+        break;
+
+      case DRUPAL_REQUIRED:
+        $mode_text = 'required';
+        break;
+    }
+    $this->setCommentSettings('comment_preview', $mode, 'Comment preview ' . $mode_text . '.');
+  }
+
+  /**
+   * Sets the value governing whether the comment form is on its own page.
+   *
+   * @param boolean $enabled
+   *   TRUE if the comment form should be displayed on the same page as the
+   *   comments; FALSE if it should be displayed on its own page.
+   */
+  function setCommentForm($enabled) {
+    $this->setCommentSettings('comment_form_location', ($enabled ? COMMENT_FORM_BELOW : COMMENT_FORM_SEPARATE_PAGE), 'Comment controls ' . ($enabled ? 'enabled' : 'disabled') . '.');
+  }
+
+  /**
+   * Sets the value governing restrictions on anonymous comments.
+   *
+   * @param integer $level
+   *   The level of the contact information allowed for anonymous comments:
+   *   - 0: No contact information allowed.
+   *   - 1: Contact information allowed but not required.
+   *   - 2: Contact information required.
+   */
+  function setCommentAnonymous($level) {
+    $this->setCommentSettings('comment_anonymous', $level, 'Anonymous commenting set to level ' . $level . '.');
+  }
+
+  /**
+   * Sets the value specifying the default number of comments per page.
+   *
+   * @param integer $comments
+   *   Comments per page value.
+   */
+  function setCommentsPerPage($number) {
+    $this->setCommentSettings('comment_default_per_page', $number, 'Number of comments per page set to ' . $number . '.');
+  }
+
+  /**
+   * Sets a comment settings variable for the article content type.
+   *
+   * @param string $name
+   *   Name of variable.
+   * @param string $value
+   *   Value of variable.
+   * @param string $message
+   *   Status message to display.
+   */
+  function setCommentSettings($name, $value, $message) {
+    variable_set($name . '_article', $value);
+    $this->assertTrue(TRUE, t($message)); // Display status message.
+  }
+
+  /**
+   * Checks whether the commenter's contact information is displayed.
+   *
+   * @return boolean
+   *   Contact info is available.
+   */
+  function commentContactInfoAvailable() {
+    return preg_match('/(input).*?(name="name").*?(input).*?(name="mail").*?(input).*?(name="homepage")/s', $this->drupalGetContent());
+  }
+
+  /**
+   * Performs the specified operation on the specified comment.
+   *
+   * @param object $comment
+   *   Comment to perform operation on.
+   * @param string $operation
+   *   Operation to perform.
+   * @param boolean $aproval
+   *   Operation is found on approval page.
+   */
+  function performCommentOperation($comment, $operation, $approval = FALSE) {
+    $edit = array();
+    $edit['operation'] = $operation;
+    $edit['comments[' . $comment->id . ']'] = TRUE;
+    $this->drupalPost('admin/content/comment' . ($approval ? '/approval' : ''), $edit, t('Update'));
+
+    if ($operation == 'delete') {
+      $this->drupalPost(NULL, array(), t('Delete comments'));
+      $this->assertRaw(format_plural(1, 'Deleted 1 comment.', 'Deleted @count comments.'), t('Operation "' . $operation . '" was performed on comment.'));
+    }
+    else {
+      $this->assertText(t('The update has been performed.'), t('Operation "' . $operation . '" was performed on comment.'));
+    }
+  }
+
+  /**
+   * Gets the comment ID for an unapproved comment.
+   *
+   * @param string $subject
+   *   Comment subject to find.
+   *
+   * @return integer
+   *   Comment id.
+   */
+  function getUnapprovedComment($subject) {
+    $this->drupalGet('admin/content/comment/approval');
+    preg_match('/href="(.*?)#comment-([^"]+)"(.*?)>(' . $subject . ')/', $this->drupalGetContent(), $match);
+
+    return $match[2];
+  }
+}
diff --git a/core/modules/rdf/rdf.test b/core/modules/rdf/rdf.test
index 0c60f4188e9b3b33350d7042449b12ad153756ba..564408ef0625dfd46f6905c648e32dee503d015e 100644
--- a/core/modules/rdf/rdf.test
+++ b/core/modules/rdf/rdf.test
@@ -7,6 +7,7 @@
 
 use Drupal\node\Node;
 use Drupal\simpletest\WebTestBase;
+use Drupal\comment\Tests\CommentTestBase;
 
 class RdfMappingHookTestCase extends WebTestBase {
   public static function getInfo() {
@@ -416,7 +417,7 @@ class RdfMappingDefinitionTestCase extends TaxonomyWebTestCase {
   }
 }
 
-class RdfCommentAttributesTestCase extends CommentHelperCase {
+class RdfCommentAttributesTestCase extends CommentTestBase {
 
   public static function getInfo() {
     return array(
diff --git a/core/modules/user/user.test b/core/modules/user/user.test
index 7671eba9a0c7fa2347b992e42682845229b78a57..57a37139ad4cd712361f1d8562f343e905f5b452 100644
--- a/core/modules/user/user.test
+++ b/core/modules/user/user.test
@@ -1946,7 +1946,7 @@ class UserSignatureTestCase extends WebTestBase {
     $this->drupalPost(NULL, array(), t('Save'));
 
     // Get the comment ID. (This technique is the same one used in the Comment
-    // module's CommentHelperCase test case.)
+    // module's CommentTestBase test case.)
     preg_match('/#comment-([0-9]+)/', $this->getURL(), $match);
     $comment_id = $match[1];