diff --git a/product/ERP5Type/tests/utils.py b/product/ERP5Type/tests/utils.py
index 39a37a0bb4ac5b90ba01b4ddc241329c671745f0..19ecefa1729bd9671cd07438450539dfbe782577 100644
--- a/product/ERP5Type/tests/utils.py
+++ b/product/ERP5Type/tests/utils.py
@@ -61,7 +61,7 @@ class DummyMailHost(MailHost):
   _last_message = ()
   _previous_message = ()
   _message_list = []
-  def _send( self, mfrom, mto, messageText ):
+  def _send( self, mfrom, mto, messageText, immediate=False ):
     """Record message in _last_message."""
     self._previous_message = self._last_message
     self._last_message = (mfrom, mto, messageText)