diff --git a/core/modules/system/lib/Drupal/system/Tests/DrupalKernel/DrupalKernelTest.php b/core/modules/system/lib/Drupal/system/Tests/DrupalKernel/DrupalKernelTest.php
index 61915d6..87c7019 100644
--- a/core/modules/system/lib/Drupal/system/Tests/DrupalKernel/DrupalKernelTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/DrupalKernel/DrupalKernelTest.php
@@ -119,11 +119,6 @@ function testCompileDIC() {
    */
   public function testSerialization() {
     $classloader = drupal_classloader();
-    // @todo: write a memory based storage backend for testing.
-    $module_enabled = array(
-      'system' => 'system',
-      'user' => 'user',
-    );
     $kernel = new DrupalKernel('testing', FALSE, $classloader);
 
     $string = serialize($kernel);