Fatal error: Uncaught Error: Class "Drupal\KernelTests\Core\Plugin\Discovery\DiscoveryTestBase" not found in /home/www/drupal8/test/core/tests/Drupal/KernelTests/Core/Plugin/Discovery/StaticDiscoveryTest.php:12
Stack trace:
#0 {main}
thrown in /home/www/drupal8/test/core/tests/Drupal/KernelTests/Core/Plugin/Discovery/StaticDiscoveryTest.php on line 12