Fatal error: Uncaught Error: Class "Drupal\FunctionalTests\Image\ToolkitTestBase" not found in /home/www/drupal8/test/core/tests/Drupal/FunctionalTests/Image/ToolkitTest.php:10 Stack trace: #0 {main} thrown in /home/www/drupal8/test/core/tests/Drupal/FunctionalTests/Image/ToolkitTest.php on line 10