Fatal error: Uncaught Error: Interface "Symfony\Component\Routing\RouterInterface" not found in /home/www/drupal8/test/core/tests/Drupal/Tests/Core/Routing/TestRouterInterface.php:11 Stack trace: #0 {main} thrown in /home/www/drupal8/test/core/tests/Drupal/Tests/Core/Routing/TestRouterInterface.php on line 11