Fatal error: Uncaught Error: Class "Drupal\KernelTests\KernelTestBase" not found in /home/www/drupal8/test/core/modules/rdf/tests/src/Kernel/CrudTest.php:12
Stack trace:
#0 {main}
thrown in /home/www/drupal8/test/core/modules/rdf/tests/src/Kernel/CrudTest.php on line 12