Fatal error: Uncaught Error: Class "Drupal\KernelTests\KernelTestBase" not found in /home/www/drupal8/test/modules/migrate_plus/tests/src/Kernel/Plugin/migrate/process/EntityGenerateTest.php:21 Stack trace: #0 {main} thrown in /home/www/drupal8/test/modules/migrate_plus/tests/src/Kernel/Plugin/migrate/process/EntityGenerateTest.php on line 21