              'email': 'tom@example.com',
              'content': 'x' * 1001,
              'created': datetime.datetime(2012, 1, 1)
          }
          self.long_text = LongText('test test test test')
  
      def test_create(self):
          serializer = CommentSerializer(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).']})
 
</s> remove     def test_update_long_text(self):
        data = {
            'content' : 'Lorem ipsum dolor sit amet.'
        }
        serializer = LongTextSerializer(data, self.long_text)
        self.assertEquals(serializer.is_valid(), True)
        self.assertEquals(data['content'], self.long_text.content)

 </s> add  </s> remove class LongText(object):
    def __init__(self, content):
        self.content = content

    def __eq__(self, other):
        return all([getattr(self, attr) == getattr(other, attr)
                    for attr in ('content',)])


class LongTextSerializer(serializers.Serializer):
    content = serializers.TextField()

    def restore_object(self, data, instance=None):
        if instance is None:
            return LongText(**data)
        for key, val in data.items():
            setattr(instance, key, val)
        return instance


 </s> add  </s> remove class TextField(WritableField):
    type_name = 'TextField'

    def from_native(self, value):
        if isinstance(value, basestring) or value is None:
            return value
        return smart_unicode(value)
 </s> add 
              'email': 'tom@example.com',
              'content': 'x' * 1001,
              'created': datetime.datetime(2012, 1, 1)
          }

  
      def test_create(self):
          serializer = CommentSerializer(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).']})
keep keep keep keep replace keep keep keep keep keep
 Removed serializer.TextField and related tests 
rest_framework/tests/serializer.py