diff --git a/apiclient/http.py b/apiclient/http.py
index f713ec8..094271f 100644
--- a/apiclient/http.py
+++ b/apiclient/http.py
@@ -150,7 +150,7 @@
       resp, content = self.responses[methodId]
       return HttpRequestMock(resp, content, postproc)
     else:
-      model = JsonModel()
+      model = JsonModel(False)
       return HttpRequestMock(None, '{}', model.response)