diff --git a/core/modules/system/tests/modules/ajax_test/ajax_test.module b/core/modules/system/tests/modules/ajax_test/ajax_test.module
index d81da66..5be5911 100644
--- a/core/modules/system/tests/modules/ajax_test/ajax_test.module
+++ b/core/modules/system/tests/modules/ajax_test/ajax_test.module
@@ -5,73 +5,9 @@
  * Helper module for Ajax framework tests.
  */
 
-use Drupal\Core\Ajax\AjaxResponse;
-use Drupal\Core\Ajax\AlertCommand;
-use Drupal\Core\Ajax\OpenDialogCommand;
-use Drupal\Core\Ajax\OpenModalDialogCommand;
-use Drupal\Core\Ajax\CloseDialogCommand;
-use Drupal\Core\Ajax\HtmlCommand;
 use Drupal\Core\Url;
 
 /**
- * Menu callback: Returns an element suitable for use by
- * \Drupal\Core\Ajax\AjaxResponse::ajaxRender().
- *
- * Additionally ensures that \Drupal\Core\Ajax\AjaxResponse::ajaxRender()
- * incorporates JavaScript settings generated during the page request by
- * invoking _drupal_add_js() with a dummy setting.
- *
- * @deprecated \Drupal\ajax_test\Controller\AjaxTestController::render()
- */
-function ajax_test_render() {
-  $attached = array(
-    '#attached' => array(
-      'drupalSettings' => array(
-        'ajax' => 'test',
-      ),
-    ),
-  );
-  // @todo Why is this being tested via an explicit drupal_render() call?
-  drupal_render($attached);
-  drupal_process_attached($attached);
-  $response = new AjaxResponse();
-  return $response;
-}
-
-/**
- * Menu callback: Returns an AjaxResponse; settings command set last.
- *
- * Helps verifying AjaxResponse reorders commands to ensure correct execution.
- *
- * @deprecated \Drupal\ajax_test\Controller\AjaxTestController::order()
- */
-function ajax_test_order() {
-  $response = new AjaxResponse();
-  // HTML insertion command.
-  $response->addCommand(new HtmlCommand('body', 'Hello, world!'));
-  $build['#attached']['library'][] = 'ajax_test/order';
-  drupal_process_attached($build);
-
-  return $response;
-}
-
-/**
- * Menu callback: Returns AJAX element with #error property set.
- *
- * @deprecated \Drupal\ajax_test\Controller\AjaxTestController::renderError()
- */
-function ajax_test_error() {
-  $message = '';
-  $query = \Drupal::request()->query;
-  if ($query->has('message')) {
-    $message = $query->get('message');
-  }
-  $response = new AjaxResponse();
-  $response->addCommand(new AlertCommand($message));
-  return $response;
-}
-
-/**
  * Returns example content for dialog tests.
  */
 function ajax_test_dialog_contents() {
@@ -95,14 +31,3 @@ function ajax_test_dialog_contents() {
 
   return $content;
 }
-
-/**
- * Menu callback: Close the ajax dialog.
- *
- * @deprecated \Drupal\ajax_test\Controller\AjaxTestController::dialogClose()
- */
-function ajax_test_dialog_close() {
-  $response = new AjaxResponse();
-  $response->addCommand(new CloseDialogCommand('#ajax-test-dialog-wrapper-1'));
-  return $response;
-}
diff --git a/core/modules/system/tests/modules/ajax_test/src/Controller/AjaxTestController.php b/core/modules/system/tests/modules/ajax_test/src/Controller/AjaxTestController.php
index ab25fde..fc85b2c 100644
--- a/core/modules/system/tests/modules/ajax_test/src/Controller/AjaxTestController.php
+++ b/core/modules/system/tests/modules/ajax_test/src/Controller/AjaxTestController.php
@@ -7,6 +7,10 @@
 
 namespace Drupal\ajax_test\Controller;
 
+use Drupal\Core\Ajax\AjaxResponse;
+use Drupal\Core\Ajax\AlertCommand;
+use Drupal\Core\Ajax\CloseDialogCommand;
+use Drupal\Core\Ajax\HtmlCommand;
 use Drupal\Core\Url;
 
 /**
@@ -19,32 +23,62 @@ class AjaxTestController {
    */
   public function dialogContents() {
     // Re-use the utility method that returns the example content.
+    // This is a regular render array; the keys do not have special meaning.
     return ajax_test_dialog_contents();
   }
 
   /**
-   * @todo Remove ajax_test_render().
+   *Returns an element suitable for use by
+   * \Drupal\Core\Ajax\AjaxResponse::ajaxRender().
+   * Additionally ensures that \Drupal\Core\Ajax\AjaxResponse::ajaxRender()
+   * incorporates JavaScript settings generated during the page request by
+   * invoking _drupal_add_js() with a dummy setting.
    */
   public function render() {
-    return ajax_test_render();
+    $attached = array(
+      '#attached' => array(
+        'drupalSettings' => array(
+          'ajax' => 'test',
+        ),
+      ),
+    );
+    // @todo Why is this being tested via an explicit drupal_render() call?
+    drupal_render($attached);
+    drupal_process_attached($attached);
+    $response = new AjaxResponse();
+    return $response;
   }
 
   /**
-   * @todo Remove ajax_test_order().
+   * Returns an AjaxResponse; settings command set last.
+   * Helps verifying AjaxResponse reorders commands to ensure correct execution.
    */
   public function order() {
-    return ajax_test_order();
+    $response = new AjaxResponse();
+    // HTML insertion command.
+    $response->addCommand(new HtmlCommand('body', 'Hello, world!'));
+    $build['#attached']['library'][] = 'ajax_test/order';
+    drupal_process_attached($build);
+
+    return $response;
   }
 
   /**
-   * @todo Remove ajax_test_error().
+   * Menu callback: Returns AJAX element with #error property set.
    */
   public function renderError() {
-    return ajax_test_error();
+    $message = '';
+    $query = \Drupal::request()->query;
+    if ($query->has('message')) {
+      $message = $query->get('message');
+    }
+    $response = new AjaxResponse();
+    $response->addCommand(new AlertCommand($message));
+    return $response;
   }
 
   /**
-   * @todo Remove ajax_test_dialog().
+   *
    */
   public function dialog() {
     // Add two wrapper elements for testing non-modal dialogs. Modal dialogs use
@@ -137,10 +171,12 @@ public function dialog() {
   }
 
   /**
-   * @todo Remove ajax_test_dialog_close().
+   * Close the ajax dialog.
    */
   public function dialogClose() {
-    return ajax_test_dialog_close();
+    $response = new AjaxResponse();
+    $response->addCommand(new CloseDialogCommand('#ajax-test-dialog-wrapper-1'));
+    return $response;
   }
 
 }