Warn if views return non-Response objects.

2 files changed, 13 insertions, 1 deletions

diff --git a/repoze/bfg/tests/test_wsgiadapter.py b/repoze/bfg/tests/test_wsgiadapter.py
index 4555cbba5..500c7b138 100644
--- a/repoze/bfg/tests/test_wsgiadapter.py
+++ b/repoze/bfg/tests/test_wsgiadapter.py
@@ -80,7 +80,17 @@ class NaiveWSGIAdapterTests(unittest.TestCase, PlacelessSetup):
         self.assertEqual(result, ['Hello world'])
         self.assertEqual(start_response.headers, ())
         self.assertEqual(start_response.status, '200 OK')
- 
+
+    def test_view_returns_nonresponse(self):
+        request = DummyRequest()
+        def view(request):
+            return None
+        context = DummyContext()
+        adapter = self._makeOne(context, request, view)
+        environ = {}
+        start_response = DummyStartResponse()
+        self.assertRaises(ValueError, adapter, environ, start_response)
+
     def test_view_fails_security_policy(self):
         import zope.component
         gsm = zope.component.getGlobalSiteManager()
diff --git a/repoze/bfg/wsgiadapter.py b/repoze/bfg/wsgiadapter.py
index 9b35c6aa2..968092a4e 100644
--- a/repoze/bfg/wsgiadapter.py
+++ b/repoze/bfg/wsgiadapter.py
@@ -55,6 +55,8 @@ class NaiveWSGIViewAdapter:
             response = view
         else:
             response =  mapply(view, positional = (), keyword = kwdict)
+        if not isResponse(response):
+            raise ValueError('response was not IResponse: %s' % response)
         if not catch_response:
             catch_response = (response.status, response.headerlist)
         start_response(*catch_response)