Fatal error: Uncaught Error: Class "Drupal\FunctionalJavascriptTests\WebDriverTestBase" not found in /home/www/drupal8/test/core/modules/file/tests/src/FunctionalJavascript/FileFieldValidateTest.php:15 Stack trace: #0 {main} thrown in /home/www/drupal8/test/core/modules/file/tests/src/FunctionalJavascript/FileFieldValidateTest.php on line 15