Fatal error: Uncaught Error: Class "Drupal\webform\Tests\Element\WebformElementTestBase" not found in /home/www/drupal8/test/modules/webform/src/Tests/Element/WebformElementCompositeTest.php:12
Stack trace:
#0 {main}
thrown in /home/www/drupal8/test/modules/webform/src/Tests/Element/WebformElementCompositeTest.php on line 12