diff -r a5d7fcde74c9 -r f5f83d72ba8d cubicweb/devtools/testlib.py
--- a/cubicweb/devtools/testlib.py	Wed May 08 21:37:13 2019 +0200
+++ b/cubicweb/devtools/testlib.py	Fri May 10 15:58:01 2019 +0200
@@ -446,10 +446,7 @@
                               reverse_primary_email=user)
         user.cw_clear_relation_cache('in_group', 'subject')
         if commit:
-            try:
-                req.commit()  # req is a session
-            except AttributeError:
-                req.cnx.commit()
+            getattr(req, 'cnx', req).commit()
         return user
 
     # other utilities #########################################################