--- a/server/session.py	Fri Sep 14 14:15:39 2012 +0200
+++ b/server/session.py	Fri Sep 21 15:03:59 2012 +0200
@@ -1213,6 +1213,9 @@
             return 'en'
         return None
 
+    def prefered_language(self, language=None):
+        # mock CWUser.prefered_language, mainly for testing purpose
+        return self.property_value('ui.language')
 
 from logging import getLogger
 from cubicweb import set_log_methods