              str('TestSerializer'),
              (serializers.ModelSerializer,),
              attrs
          )
          with self.assertRaises(AttributeError):
              serializer.fields
  
  
  @unittest.skipIf(get_version() < '1.6.0', 'Upstream behaviour changed in v1.6')
 
</s> remove             TestSerializer(data={'name': 'foo'})
 </s> add             serializer.fields </s> remove         self.assertRaises(AssertionError, PersonSerializerInvalidReadOnly, [])
 </s> add         serializer = PersonSerializerInvalidReadOnly()
        with self.assertRaises(AssertionError):
            serializer.fields </s> remove     def test_exception_for_incorect_fk(self):
 </s> add     def test_exception_for_incorrect_fk(self): </s> remove         self.fields = self.get_fields()
 </s> add 
        serializer = TestSerializer(data={'name': 'foo'})
              str('TestSerializer'),
              (serializers.ModelSerializer,),
              attrs
          )
        serializer = TestSerializer(data={'name': 'foo'})
          with self.assertRaises(AttributeError):
              serializer.fields
  
  
  @unittest.skipIf(get_version() < '1.6.0', 'Upstream behaviour changed in v1.6')
keep keep keep add keep keep keep keep keep
 Set up serializer fields lazily on-demand.

This avoids AppRegistryNotReady problems in Django 1.7 with nested serializers,
which are instantiated at import time, possibly before Django's app registry is
fully populated. 
tests/test_relations.py