Fatal error: Uncaught Error: Class "Drupal\webform\Tests\WebformTestBase" not found in /home/www/drupal8/test/modules/webform/src/Tests/Handler/WebformHandlerActionTest.php:15
Stack trace:
#0 {main}
thrown in /home/www/drupal8/test/modules/webform/src/Tests/Handler/WebformHandlerActionTest.php on line 15