      def test_foreign_key_with_empty(self):
          """
          Regression test for #1072
  
          https://github.com/tomchristie/django-rest-framework/issues/1072
          """
          serializer = NullableForeignKeySourceSerializer()
          assert serializer.data['target'] is None
  
      def test_foreign_key_not_required(self):
 
</s> remove         Regression test for https://github.com/tomchristie/django-rest-framework/issues/4661
 </s> add         Regression test for https://github.com/encode/django-rest-framework/issues/4661 </s> remove         https://github.com/tomchristie/django-rest-framework/issues/285
 </s> add         https://github.com/encode/django-rest-framework/issues/285 </s> remove         https://github.com/tomchristie/django-rest-framework/issues/1196
 </s> add         https://github.com/encode/django-rest-framework/issues/1196 </s> remove         Regression test for https://github.com/tomchristie/django-rest-framework/pull/3164
 </s> add         Regression test for https://github.com/encode/django-rest-framework/pull/3164 </s> remove         cf. [#1810](https://github.com/tomchristie/django-rest-framework/pull/1810)
 </s> add         cf. [#1810](https://github.com/encode/django-rest-framework/pull/1810)
        https://github.com/encode/django-rest-framework/issues/1072
      def test_foreign_key_with_empty(self):
          """
          Regression test for #1072
  
        https://github.com/encode/django-rest-framework/issues/1072
          """
          serializer = NullableForeignKeySourceSerializer()
          assert serializer.data['target'] is None
  
      def test_foreign_key_not_required(self):
keep keep keep keep replace keep keep keep keep keep
 Update links after moving to encode org 
tests/test_relations_pk.py