Fatal error: Uncaught Error: Class "Drupal\Tests\contact\Functional\Rest\MessageResourceTestBase" not found in /home/www/drupal8/test/core/modules/contact/tests/src/Functional/Rest/MessageXmlCookieTest.php:11
Stack trace:
#0 {main}
thrown in /home/www/drupal8/test/core/modules/contact/tests/src/Functional/Rest/MessageXmlCookieTest.php on line 11