Allow context to be provided to get_serializer (#7298)

* Test generics serializer behavior

* Allow context to be provided to get_serializer

rest_framework/generics.py

@@ -106,7 +106,7 @@ class GenericAPIView(views.APIView):
         deserializing input, and for serializing output.
         """
         serializer_class = self.get_serializer_class()
-        kwargs['context'] = self.get_serializer_context()
+        kwargs.setdefault('context', self.get_serializer_context())
         return serializer_class(*args, **kwargs)
 
     def get_serializer_class(self):

tests/test_generics.py

@@ -662,3 +662,33 @@ class GetObjectOr404Tests(TestCase):
     def test_get_object_or_404_with_invalid_string_for_uuid(self):
         with pytest.raises(Http404):
             generics.get_object_or_404(UUIDForeignKeyTarget, pk='not-a-uuid')
+
+
+class TestSerializer(TestCase):
+
+    def test_serializer_class_not_provided(self):
+        class NoSerializerClass(generics.GenericAPIView):
+            pass
+
+        with pytest.raises(AssertionError) as excinfo:
+            NoSerializerClass().get_serializer_class()
+
+        assert str(excinfo.value) == (
+            "'NoSerializerClass' should either include a `serializer_class` "
+            "attribute, or override the `get_serializer_class()` method.")
+
+    def test_given_context_not_overridden(self):
+        context = object()
+
+        class View(generics.ListAPIView):
+            serializer_class = serializers.Serializer
+
+            def list(self, request):
+                response = Response()
+                response.serializer = self.get_serializer(context=context)
+                return response
+
+        response = View.as_view()(factory.get('/'))
+        serializer = response.serializer
+
+        assert serializer.context is context