diff --git a/core/modules/config/lib/Drupal/config/Tests/ConfigEntityListTest.php b/core/modules/config/lib/Drupal/config/Tests/ConfigEntityListTest.php
index 4ca6e2f..e7a472c 100644
--- a/core/modules/config/lib/Drupal/config/Tests/ConfigEntityListTest.php
+++ b/core/modules/config/lib/Drupal/config/Tests/ConfigEntityListTest.php
@@ -144,6 +144,9 @@ function testList() {
       'delete' => array(
         'title' => t('Delete'),
         'href' => $uri['path'] . '/delete',
+        'ajax' => array(
+          'accepts' => 'application/vnd.drupal-modal',
+        ),
         'options' => $uri['options'],
         'weight' => 100,
       ),