Fatal error: Uncaught Error: Class "Drupal\Tests\media\FunctionalJavascript\MediaJavascriptTestBase" not found in /home/www/drupal8/test/core/modules/media/tests/src/FunctionalJavascript/MediaDisplayTest.php:18 Stack trace: #0 {main} thrown in /home/www/drupal8/test/core/modules/media/tests/src/FunctionalJavascript/MediaDisplayTest.php on line 18