Fatal error: Uncaught Error: Class "Drupal\Tests\user\Functional\Rest\UserResourceTestBase" not found in /home/www/drupal8/test/core/modules/user/tests/src/Functional/Rest/UserJsonCookieTest.php:10 Stack trace: #0 {main} thrown in /home/www/drupal8/test/core/modules/user/tests/src/Functional/Rest/UserJsonCookieTest.php on line 10