diff --git a/rest_framework/test.py b/rest_framework/test.py
index df5a5b3b3..284bcee07 100644
--- a/rest_framework/test.py
+++ b/rest_framework/test.py
@@ -36,7 +36,7 @@ class APIRequestFactory(DjangoRequestFactory):
         """
 
         if not data:
-            return ('', None)
+            return ('', content_type)
 
         assert format is None or content_type is None, (
             'You may not set both `format` and `content_type`.'