Add a test case to prevent future regressions

Author: apetitpa

src/Symfony/Component/Validator/Tests/Constraints/EmailValidatorTest.php

@@ -96,6 +96,7 @@ public function getInvalidEmails()
             array('example@'),
             array('example@localhost'),
             array('[email protected] bar'),
+            array('[email protected]@'),
         );
     }