[Form] fix tests

Author: xabbuh

src/Symfony/Component/Form/Tests/Extension/Validator/Constraints/FormValidatorTest.php

@@ -135,6 +135,8 @@ public function testMissingConstraintIndex()
         $form = new FormBuilder('name', '\stdClass', $this->dispatcher, $this->factory);
         $form = $form->setData($object)->getForm();
 
+        $this->expectValidateAt(0, 'data', $object, 'Default');
+
         $this->validator->validate($form, new Form());
 
         $this->assertNoViolation();