Fatal error: Uncaught Error: Class "Drupal\webform\Tests\WebformTestBase" not found in /home/www/drupal8/test/modules/webform/src/Tests/Composite/WebformCompositeFormatTest.php:16 Stack trace: #0 {main} thrown in /home/www/drupal8/test/modules/webform/src/Tests/Composite/WebformCompositeFormatTest.php on line 16