Fatal error: Uncaught Error: Class "Drupal\Core\Config\ConfigException" not found in /home/www/drupal8/test/core/lib/Drupal/Core/Config/ConfigValueException.php:8
Stack trace:
#0 {main}
thrown in /home/www/drupal8/test/core/lib/Drupal/Core/Config/ConfigValueException.php on line 8