diff --git a/trytond/trytond/tests/test_res.py b/trytond/trytond/tests/test_res.py
index 940bf003cb..266129bcdc 100644
--- a/trytond/trytond/tests/test_res.py
+++ b/trytond/trytond/tests/test_res.py
@@ -17,6 +17,13 @@ class ResTestCase(ModuleTestCase):
     'Test res module'
     module = 'res'
 
+    @with_transaction()
+    def tearDown(self):
+        pool = Pool()
+        Warning_ = pool.get('res.user.warning')
+        Warning_.delete(Warning_.search([]))
+        Transaction().commit()
+
     @unittest.skipUnless(PIL, "Avatars are not generated without PIL")
     @with_transaction()
     def test_user_avatar(self):
@@ -44,14 +51,12 @@ class ResTestCase(ModuleTestCase):
         pool = Pool()
         Warning_ = pool.get('res.user.warning')
 
-        user_id = Transaction().user
-        Warning_.create([{
-                    'user': user_id,
-                    'name': 'test',
-                    }])
+        with Transaction().new_transaction():
+            Warning_.skip('test')
+            self.assertFalse(Warning_.check('test'))
 
-        self.assertFalse(Warning_.check('test'))
-        self.assertFalse(Warning_.search([]))
+        with Transaction().new_transaction():
+            self.assertTrue(Warning_.check('test'))
 
     @with_transaction()
     def test_user_warning_always_ignored(self):
@@ -59,15 +64,12 @@ class ResTestCase(ModuleTestCase):
         pool = Pool()
         Warning_ = pool.get('res.user.warning')
 
-        user_id = Transaction().user
-        Warning_.create([{
-                    'user': user_id,
-                    'name': 'test',
-                    'always': True,
-                    }])
+        with Transaction().new_transaction():
+            Warning_.skip('test', always=True)
+            self.assertFalse(Warning_.check('test'))
 
-        self.assertFalse(Warning_.check('test'))
-        self.assertTrue(Warning_.search([]))
+        with Transaction().new_transaction():
+            self.assertFalse(Warning_.check('test'))
 
     @with_transaction()
     def test_user_warning_reentrant(self):
@@ -75,11 +77,7 @@ class ResTestCase(ModuleTestCase):
         pool = Pool()
         Warning_ = pool.get('res.user.warning')
 
-        user_id = Transaction().user
-        Warning_.create([{
-                    'user': user_id,
-                    'name': 'test',
-                    }])
+        Warning_.skip('test')
 
         self.assertFalse(Warning_.check('test'))
         self.assertFalse(Warning_.check('test'))