diff --git a/core/modules/ckeditor/src/Tests/CKEditorTest.php b/core/modules/ckeditor/src/Tests/CKEditorTest.php
index 9133ee0..91fc410 100644
--- a/core/modules/ckeditor/src/Tests/CKEditorTest.php
+++ b/core/modules/ckeditor/src/Tests/CKEditorTest.php
@@ -8,8 +8,7 @@
 namespace Drupal\ckeditor\Tests;
 
 use Drupal\simpletest\KernelTestBase;
-use Drupal\editor\Plugin\EditorManager;
-use Drupal\ckeditor\Plugin\Editor\CKEditor;
+use Drupal\language\Entity\ConfigurableLanguage;
 
 /**
  * Tests for the 'CKEditor' text editor plugin.
@@ -368,6 +367,10 @@ function testLanguages() {
     // Language codes only in CKEditor.
     $this->assertTrue($langcodes['en-au'] == 'en-au', '"en-au" properly resolved');
     $this->assertTrue($langcodes['sr-latn'] == 'sr-latn', '"sr-latn" properly resolved');
+
+    // No locale module, so even though languages are enabled, CK should still
+    // be in English.
+    $this->assertCKEditorLanguage('en');
   }
 
   /**
@@ -382,6 +385,20 @@ function testJSTranslation() {
     $localeStorage = $this->container->get('locale.storage');
     $string = $localeStorage->findString(array('source' => 'Edit Link', 'context' => ''));
     $this->assertTrue(!empty($string), 'String from JavaScript file saved.');
+
+    // With locale module, CK should not adhere to the language selected.
+    $this->assertCKEditorLanguage();
+  }
+
+  /**
+   * Assert that CKEditor picks the expected language when French is default.
+   */
+  protected function assertCKEditorLanguage($langcode = 'fr') {
+    ConfigurableLanguage::createFromLangcode('fr')->save();
+    \Drupal::config('system.site')->set('langcode', 'fr');
+    $editor = entity_load('editor', 'filtered_html');
+    $settings = $this->ckeditor->getJSSettings($editor);
+    $this->assertEqual($settings['language'], $langcode);
   }
 
   protected function getDefaultInternalConfig() {