.../editor/src/Tests/QuickEditIntegrationTest.php        | 16 +++++++++++++++-
 core/modules/system/src/Tests/Ajax/CommandsTest.php      | 13 ++++++++++++-
 core/tests/Drupal/Tests/Core/Ajax/AjaxResponseTest.php   | 13 ++++++++++++-
 3 files changed, 39 insertions(+), 3 deletions(-)

diff --git a/core/modules/editor/src/Tests/QuickEditIntegrationTest.php b/core/modules/editor/src/Tests/QuickEditIntegrationTest.php
index ab48237..cb67445 100644
--- a/core/modules/editor/src/Tests/QuickEditIntegrationTest.php
+++ b/core/modules/editor/src/Tests/QuickEditIntegrationTest.php
@@ -8,6 +8,7 @@
 namespace Drupal\editor\Tests;
 
 use Drupal\Component\Serialization\Json;
+use Drupal\Core\EventSubscriber\AjaxSubscriber;
 use Drupal\Core\Language\LanguageInterface;
 use Drupal\quickedit\EditorSelector;
 use Drupal\quickedit\MetadataGenerator;
@@ -16,6 +17,8 @@
 use Drupal\quickedit_test\MockEditEntityFieldAccessCheck;
 use Drupal\editor\EditorController;
 use Symfony\Component\HttpFoundation\Request;
+use Symfony\Component\HttpKernel\Event\FilterResponseEvent;
+use Symfony\Component\HttpKernel\HttpKernelInterface;
 
 /**
  * Tests Edit module integration (Editor module's inline editing support).
@@ -214,7 +217,18 @@ public function testGetUntransformedTextCommand() {
         'data' => 'Test',
       )
     );
-    $this->assertEqual(Json::encode($expected), $response->prepare($request)->getContent(), 'The GetUntransformedTextCommand AJAX command works correctly.');
+
+    $ajax_response_attachments_processor = \Drupal::service('ajax_response.attachments_processor');
+    $subscriber = new AjaxSubscriber($ajax_response_attachments_processor);
+    $event = new FilterResponseEvent(
+      \Drupal::service('http_kernel'),
+      $request,
+      HttpKernelInterface::MASTER_REQUEST,
+      $response
+    );
+    $subscriber->onResponse($event);
+
+    $this->assertEqual(Json::encode($expected), $response->getContent(), 'The GetUntransformedTextCommand AJAX command works correctly.');
   }
 
 }
diff --git a/core/modules/system/src/Tests/Ajax/CommandsTest.php b/core/modules/system/src/Tests/Ajax/CommandsTest.php
index 969ec9c..711aad2 100644
--- a/core/modules/system/src/Tests/Ajax/CommandsTest.php
+++ b/core/modules/system/src/Tests/Ajax/CommandsTest.php
@@ -23,7 +23,10 @@
 use Drupal\Core\Ajax\RemoveCommand;
 use Drupal\Core\Ajax\RestripeCommand;
 use Drupal\Core\Ajax\SettingsCommand;
+use Drupal\Core\EventSubscriber\AjaxSubscriber;
 use Symfony\Component\HttpFoundation\Request;
+use Symfony\Component\HttpKernel\Event\FilterResponseEvent;
+use Symfony\Component\HttpKernel\HttpKernelInterface;
 
 /**
  * Performs tests on AJAX framework commands.
@@ -133,7 +136,15 @@ public function testAttachedSettings() {
         'drupalSettings' => ['foo' => 'bar'],
       ]);
 
-      $response->prepare(new Request());
+      $ajax_response_attachments_processor = \Drupal::service('ajax_response.attachments_processor');
+      $subscriber = new AjaxSubscriber($ajax_response_attachments_processor);
+      $event = new FilterResponseEvent(
+        \Drupal::service('http_kernel'),
+        new Request(),
+        HttpKernelInterface::MASTER_REQUEST,
+        $response
+      );
+      $subscriber->onResponse($event);
       $expected = [
         'command' => 'settings',
       ];
diff --git a/core/tests/Drupal/Tests/Core/Ajax/AjaxResponseTest.php b/core/tests/Drupal/Tests/Core/Ajax/AjaxResponseTest.php
index 19bbe8d..482bf75 100644
--- a/core/tests/Drupal/Tests/Core/Ajax/AjaxResponseTest.php
+++ b/core/tests/Drupal/Tests/Core/Ajax/AjaxResponseTest.php
@@ -8,9 +8,12 @@
 namespace Drupal\Tests\Core\Ajax;
 
 use Drupal\Core\Ajax\AjaxResponse;
+use Drupal\Core\EventSubscriber\AjaxSubscriber;
 use Drupal\Core\Render\Element\Ajax;
 use Drupal\Tests\UnitTestCase;
 use Symfony\Component\HttpFoundation\Request;
+use Symfony\Component\HttpKernel\Event\FilterResponseEvent;
+use Symfony\Component\HttpKernel\HttpKernelInterface;
 
 /**
  * @coversDefaultClass \Drupal\Core\Ajax\AjaxResponse
@@ -81,7 +84,15 @@ public function testPrepareResponseForIeFormRequestsWithFileUpload() {
     $response = new AjaxResponse([]);
     $response->headers->set('Content-Type', 'application/json; charset=utf-8');
 
-    $response->prepare($request);
+    $ajax_response_attachments_processor = $this->getMock('\Drupal\Core\Render\AttachmentsResponseProcessorInterface');
+    $subscriber = new AjaxSubscriber($ajax_response_attachments_processor);
+    $event = new FilterResponseEvent(
+      $this->getMock('\Symfony\Component\HttpKernel\HttpKernelInterface'),
+      $request,
+      HttpKernelInterface::MASTER_REQUEST,
+      $response
+    );
+    $subscriber->onResponse($event);
     $this->assertEquals('text/html; charset=utf-8', $response->headers->get('Content-Type'));
     $this->assertEquals($response->getContent(), '<textarea>[]</textarea>');
   }