diff --git a/openerp/tests/test_orm.py b/openerp/tests/test_orm.py
index 9e2a9c4a65f..0f685e292a7 100644
--- a/openerp/tests/test_orm.py
+++ b/openerp/tests/test_orm.py
@@ -131,18 +131,7 @@ class TestORM(common.TransactionCase):
             else:
                 domain = main_domain
 
-            display_format, groupby_format = {
-                'year': ('YYYY', 'yyyy'),
-                'month': ('YYYY-MM', 'yyyy-mm'),
-                'day': ('yyyy-MM-dd', 'yyyy-mm-dd'),
-            }[interval]
-
-            datetime_format = {
-                'date': dict(interval=interval, display_format=display_format, groupby_format=groupby_format)
-            }
-            context = dict(datetime_format=datetime_format)
-
-            rg = self.partner.read_group(self.cr, self.uid, domain, ['date'], 'date', context=context)
+            rg = self.partner.read_group(self.cr, self.uid, domain, ['date'], 'date' + ':' + interval)
             result = {}
             for r in rg:
                 result[r['date']] = set(self.partner.search(self.cr, self.uid, r['__domain']))