Content is a binary string.

rest_framework/tests/test_validation.py

@@ -144,5 +144,5 @@ class TestMaxValueValidatorValidation(TestCase):
         request = factory.patch('/{0}'.format(obj.pk), {'number_value': 101}, format='json')
         view = UpdateMaxValueValidationModel().as_view()
         response = view(request, pk=obj.pk).render()
-        self.assertEqual(response.content, '{"number_value": ["Ensure this value is less than or equal to 100."]}')
+        self.assertEqual(response.content, b'{"number_value": ["Ensure this value is less than or equal to 100."]}')
         self.assertEqual(response.status_code, status.HTTP_400_BAD_REQUEST)