Fatal error: Uncaught Error: Class "Drupal\FunctionalJavascriptTests\WebDriverTestBase" not found in /home/www/drupal8/test/core/modules/file/tests/src/FunctionalJavascript/FileManagedFileElementTest.php:13 Stack trace: #0 {main} thrown in /home/www/drupal8/test/core/modules/file/tests/src/FunctionalJavascript/FileManagedFileElementTest.php on line 13