          serializer = ActionItemSerializer(data=data)
          self.assertEquals(serializer.is_valid(), False)
          self.assertEquals(serializer.errors, {'title': [u'Ensure this value has at most 200 characters (it has 201).']})
  
      def test_default_modelfield_max_length_exceeded(self):
          data = {
              'title': 'Testing "info" field...',
              'info': 'x' * 13,
          }
          serializer = ActionItemSerializer(data=data)
 
</s> remove         try:
            instance.full_clean(exclude=self.get_validation_exclusions())
        except ValidationError, err:
            self._errors = err.message_dict
            return None

 </s> add 
    def test_modelserializer_max_length_exceeded_with_custom_restore(self):
        """
        When overriding ModelSerializer.restore_object, validation tests should still apply.
        Regression test for #623.

        https://github.com/tomchristie/django-rest-framework/pull/623
        """
        data = {
            'title': 'x' * 201,
        }
        serializer = ActionItemSerializerCustomRestore(data=data)
        self.assertEquals(serializer.is_valid(), False)
        self.assertEquals(serializer.errors, {'title': [u'Ensure this value has at most 200 characters (it has 201).']})

          serializer = ActionItemSerializer(data=data)
          self.assertEquals(serializer.is_valid(), False)
          self.assertEquals(serializer.errors, {'title': [u'Ensure this value has at most 200 characters (it has 201).']})
  
    def test_modelserializer_max_length_exceeded_with_custom_restore(self):
        """
        When overriding ModelSerializer.restore_object, validation tests should still apply.
        Regression test for #623.

        https://github.com/tomchristie/django-rest-framework/pull/623
        """
        data = {
            'title': 'x' * 201,
        }
        serializer = ActionItemSerializerCustomRestore(data=data)
        self.assertEquals(serializer.is_valid(), False)
        self.assertEquals(serializer.errors, {'title': [u'Ensure this value has at most 200 characters (it has 201).']})

      def test_default_modelfield_max_length_exceeded(self):
          data = {
              'title': 'Testing "info" field...',
              'info': 'x' * 13,
          }
          serializer = ActionItemSerializer(data=data)
keep keep keep add keep keep keep keep keep keep
 Ensure model field validation is performed for ModelSerializers with a custom restore_object method.  Fixes #623. 
rest_framework/tests/serializer.py