Fatal error: Uncaught Error: Class "Drupal\Tests\file\Functional\FileFieldTestBase" not found in /home/www/drupal8/test/core/modules/file/tests/src/Functional/FileListingTest.php:14
Stack trace:
#0 {main}
thrown in /home/www/drupal8/test/core/modules/file/tests/src/Functional/FileListingTest.php on line 14