Update to Drupal 8.1.0. For more information, see https://www.drupal.org/drupal-8.1.0-release-notes

core/modules/system/tests/themes/test_basetheme/test_basetheme.theme

@@ -4,6 +4,7 @@
  * @file
  * Add hooks for tests to use.
  */
+
 use Drupal\views\Plugin\views\cache\CachePluginBase;
 use Drupal\views\ViewExecutable;
 

core/modules/system/tests/themes/test_theme/src/ThemeClass.php

@@ -1,10 +1,5 @@
 <?php
 
-/**
- * @file
- * Contains \Drupal\test_theme\ThemeClass.
- */
-
 namespace Drupal\test_theme;
 
 /**

core/modules/system/tests/themes/test_theme/test_theme.info.yml

@@ -15,7 +15,7 @@ version: VERSION
 base theme: classy
 core: 8.x
 stylesheets-remove:
-  - '@system/css/system.module.css'
+  - '@system/css/js.module.css'
 libraries:
   - test_theme/global-styling
 libraries-override:

core/modules/system/tests/themes/test_theme_nyan_cat_engine/test_theme_nyan_cat_engine.theme

@@ -1,5 +1,10 @@
 <?php
 
+/**
+ * @file
+ * Test theme.
+ */
+
 /**
  * Implements hook_preprocess_theme_test_template_test().
  */