diff --git a/core/modules/system/src/Tests/Ajax/FrameworkTest.php b/core/modules/system/src/Tests/Ajax/FrameworkTest.php
index 7b78b5c..c7ccd8b 100644
--- a/core/modules/system/src/Tests/Ajax/FrameworkTest.php
+++ b/core/modules/system/src/Tests/Ajax/FrameworkTest.php
@@ -216,14 +216,4 @@ public function testLazyLoadOverriddenCSS() {
     // cache control.
     $this->assertNoText('system.module.css?', 'Ajax lazy loading does not add overridden CSS files.');
   }
-
-  /**
-   * Tests if the 'theme_token' key of 'ajaxPageState' is computed.
-   */
-  public function testThemeToken() {
-    $this->drupalGet('ajax_forms_test_lazy_load_form');
-    $settings = $this->getDrupalSettings();
-    $this->assertTrue(is_null($settings['ajaxPageState']['theme_token']));
-  }
-
 }
diff --git a/core/modules/system/src/Tests/Theme/ThemeTokenTest.php b/core/modules/system/src/Tests/Theme/ThemeTokenTest.php
new file mode 100644
index 0000000..3c04aa2
--- /dev/null
+++ b/core/modules/system/src/Tests/Theme/ThemeTokenTest.php
@@ -0,0 +1,60 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\system\Tests\Theme\ThemeTokenTest.
+ */
+
+namespace Drupal\system\Tests\Theme;
+
+use Drupal\simpletest\WebTestBase;
+
+/**
+ * Tests the generation of 'theme_token' key in Drupal settings.
+ *
+ * @group Theme
+ */
+class ThemeTokenTest extends WebTestBase {
+
+  /**
+   * We want to visit the 'admin/structure/block' page.
+   *
+   * @var array
+   */
+  static public $modules = ['block'];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp() {
+    parent::setUp();
+    $account = $this->drupalCreateUser(['administer blocks', 'view the administration theme']);
+    $this->drupalLogin($account);
+  }
+
+  /**
+   * Tests if the 'theme_token' key of 'ajaxPageState' is computed.
+   */
+  public function testThemeToken() {
+    // Visit the block administrative page with default theme. We use that page
+    // because 'misc/ajax.js' is loaded there and we can test the token
+    // generation.
+    $this->drupalGet('admin/structure/block');
+    $settings = $this->getDrupalSettings();
+    $this->assertNull($settings['ajaxPageState']['theme_token']);
+
+    // Install 'seven' and configure it as administrative theme.
+    $this->container->get('theme_installer')->install(['seven']);
+    $this->config('system.theme')->set('admin', 'seven')->save();
+
+    // Revisit the page. This time the page is displayed using the 'seven' theme
+    // and that is different from the default theme ('classy').
+    $this->drupalGet('admin/structure/block');
+    $settings = $this->getDrupalSettings();
+    $this->assertNotNull($settings['ajaxPageState']['theme_token']);
+    // The CSRF token is a 43 length string.
+    $this->assertTrue(is_string($settings['ajaxPageState']['theme_token']));
+    $this->assertEqual(strlen($settings['ajaxPageState']['theme_token']), 43);
+  }
+
+}