          self.assertEquals(serializer.is_valid(), False)
          self.assertEquals(serializer.errors, {'content': [u'Ensure this value has at most 1000 characters (it has 1001).']})
  
      def test_update(self):
          serializer = CommentSerializer(self.data, instance=self.comment)
          self.assertEquals(serializer.is_valid(), False)
          self.assertEquals(serializer.errors, {'content': [u'Ensure this value has at most 1000 characters (it has 1001).']})
  
      def test_update_missing_field(self):
          data = {
 
</s> remove         serializer = self.serializer_class(data)
 </s> add         serializer = self.serializer_class(data=data) </s> remove         serializer = self.not_blank_model_serializer_class(self.data)
 </s> add         serializer = self.not_blank_model_serializer_class(data=self.data) </s> remove         serializer = ManyToManySourceSerializer(instance=queryset)
 </s> add         serializer = ManyToManySourceSerializer(queryset)
        serializer = CommentSerializer(self.comment, data=self.data)
          self.assertEquals(serializer.is_valid(), False)
          self.assertEquals(serializer.errors, {'content': [u'Ensure this value has at most 1000 characters (it has 1001).']})
  
      def test_update(self):
        serializer = CommentSerializer(self.comment, data=self.data)
          self.assertEquals(serializer.is_valid(), False)
          self.assertEquals(serializer.errors, {'content': [u'Ensure this value has at most 1000 characters (it has 1001).']})
  
      def test_update_missing_field(self):
          data = {
keep keep keep keep replace keep keep keep keep keep
 Swap position of `instance` and `data` keyword arguments. 
rest_framework/tests/serializer.py