- Add ` `renderer`` argument (defaulting to None) to

  ``repoze.bfg.testing.registerDummyRenderer``.  This makes it
  possible, for instance, to register a custom renderer that raises an
  exception in a unit test.

2 files changed, 18 insertions, 8 deletions

diff --git a/repoze/bfg/testing.py b/repoze/bfg/testing.py
index 77a1f05ad..6bc96fced 100644
--- a/repoze/bfg/testing.py
+++ b/repoze/bfg/testing.py
@@ -52,15 +52,16 @@ def registerEventListener(event_iface=Interface):
     registerSubscriber(subscriber, event_iface)
     return L
 
-def registerDummyRenderer(path):
-    """ Create and register a dummy template renderer at ``path``
-    (usually a relative filename ala ``templates/foo.pt``) and return
-    the renderer object.  This function is useful when testing code
-    that calls the ``render_template_to_response`` or any other
-    ``render_template*`` API of any of the built-in templating
-    systems."""
+def registerDummyRenderer(path, renderer=None):
+    """ Register a 'renderer' at ``path`` (usually a relative filename
+    ala ``templates/foo.pt``) and return the renderer object.  If the
+    ``renderer`` argument is None, a 'dummy' renderer will be used.
+    This function is useful when testing code that calls the
+    ``render_template_to_response`` or any other ``render_template*``
+    API of any of the built-in templating systems."""
     from repoze.bfg.interfaces import ITemplateRenderer
-    renderer = DummyTemplateRenderer()
+    if renderer is None:
+        renderer = DummyTemplateRenderer()
     return registerUtility(renderer, ITemplateRenderer, path)
 
 def registerView(name, result='', view=None, for_=(Interface, Interface)):
diff --git a/repoze/bfg/tests/test_testing.py b/repoze/bfg/tests/test_testing.py
index 019e0cc53..8aac7d5a0 100644
--- a/repoze/bfg/tests/test_testing.py
+++ b/repoze/bfg/tests/test_testing.py
@@ -56,6 +56,15 @@ class TestTestingFunctions(unittest.TestCase):
         response = render_template_to_response('templates/foo', foo=1, bar=2)
         self.assertEqual(dict(foo=1, bar=2), renderer._received)
 
+    def test_registerDummyRenderer_explicitrenderer(self):
+        from repoze.bfg import testing
+        def renderer(**kw):
+            raise ValueError
+        renderer = testing.registerDummyRenderer('templates/foo', renderer)
+        from repoze.bfg.chameleon_zpt import render_template_to_response
+        self.assertRaises(ValueError, render_template_to_response,
+                          'templates/foo', foo=1, bar=2)
+
     def test_registerEventListener_single(self):
         from repoze.bfg import testing
         from zope.interface import implements