Fatal error: Uncaught Error: Class "Drupal\FunctionalTests\Image\ToolkitTestBase" not found in /home/www/drupal8/test/core/modules/image/tests/src/Functional/ImageEffectsTest.php:13 Stack trace: #0 {main} thrown in /home/www/drupal8/test/core/modules/image/tests/src/Functional/ImageEffectsTest.php on line 13