Fatal error: Uncaught Error: Class "Drupal\Core\StreamWrapper\LocalReadOnlyStream" not found in /home/www/drupal8/test/core/modules/file/tests/file_test/src/StreamWrapper/DummyReadOnlyStreamWrapper.php:12 Stack trace: #0 {main} thrown in /home/www/drupal8/test/core/modules/file/tests/file_test/src/StreamWrapper/DummyReadOnlyStreamWrapper.php on line 12