Fatal error: Uncaught Error: Class "Drupal\FunctionalJavascriptTests\WebDriverTestBase" not found in /home/www/drupal8/test/core/modules/field/tests/src/FunctionalJavascript/FormJSAddMoreTest.php:16 Stack trace: #0 {main} thrown in /home/www/drupal8/test/core/modules/field/tests/src/FunctionalJavascript/FormJSAddMoreTest.php on line 16