diff --git a/core/modules/file/lib/Drupal/file/Plugin/views/field/Extension.php b/core/modules/file/lib/Drupal/file/Plugin/views/field/Extension.php
index 1663f04..e3bd6d9 100644
--- a/core/modules/file/lib/Drupal/file/Plugin/views/field/Extension.php
+++ b/core/modules/file/lib/Drupal/file/Plugin/views/field/Extension.php
@@ -3,7 +3,6 @@
 /**
  * @file
  * Definition of views_handler_field_file_extension.
- * @todo Test!
  */
 
 namespace Drupal\file\Plugin\views\field;
diff --git a/core/modules/file/lib/Drupal/file/Tests/ExtensionViewsFieldTest.php b/core/modules/file/lib/Drupal/file/Tests/ExtensionViewsFieldTest.php
index c2bd69c..f9315f6 100644
--- a/core/modules/file/lib/Drupal/file/Tests/ExtensionViewsFieldTest.php
+++ b/core/modules/file/lib/Drupal/file/Tests/ExtensionViewsFieldTest.php
@@ -16,6 +16,8 @@
  */
 class ExtensionViewsFieldTest extends ViewUnitTestBase {
 
+  public static $modules = array('file');
+
   /**
    * Views used by this test.
    *
@@ -58,7 +60,6 @@ public function testFieldExtension() {
         'id' => 'extension',
         'table' => 'views_test_data',
         'field' => 'name',
-        //'plugin_id' => 'file_extension',
       ),
     ));