Drupal test run --------------- All tests will run. Test run started: Tuesday, May 5, 2015 - 22:47 Test summary ------------ FATAL Drupal\migrate_drupal\Tests\d6\MigrateBookTest: test runner returned a non-zero error code (139). - Found database prefix 'simpletest285380' for test ID 745. Fatal error: Cannot use Symfony\Component\Validator\Constraints\Null as Null because 'Null' is a special class name in /home/berdir/Projekte/d8/core/lib/Drupal/Core/Validation/Plugin/Validation/Constraint/NullConstraint.php on line 10 FATAL Drupal\system\Tests\TypedData\TypedDataTest: test runner returned a non-zero error code (255). - Found database prefix 'simpletest577159' for test ID 1574. [05-May-2015 23:07:42 UTC] PHP Fatal error: Cannot use Symfony\Component\Validator\Constraints\Null as Null because 'Null' is a special class name in /home/berdir/Projekte/d8/core/lib/Drupal/Core/Validation/Plugin/Validation/Constraint/NullConstraint.php on line 10 - Removed test site directory. - Removed 2 leftover tables. Test run duration: 25 min 55 sec