Fatal error: Uncaught Error: Class "Drupal\Core\Form\FormBase" not found in /home/www/drupal8/test/core/lib/Drupal/Core/Entity/EntityForm.php:16
Stack trace:
#0 {main}
thrown in /home/www/drupal8/test/core/lib/Drupal/Core/Entity/EntityForm.php on line 16