diff --git a/kfet/open/tests.py b/kfet/open/tests.py
index 1d6d5529..476eb6c0 100644
--- a/kfet/open/tests.py
+++ b/kfet/open/tests.py
@@ -1,5 +1,6 @@
 import json
 from datetime import timedelta
+from unittest import mock
 
 from django.contrib.auth.models import AnonymousUser, Permission, User
 from django.test import Client
@@ -118,6 +119,11 @@ class OpenKfetViewsTest(ChannelTestCase):
     """OpenKfet views unit-tests suite."""
 
     def setUp(self):
+        # Need this (and here) because of '<client>.login' in setUp
+        patcher_messages = mock.patch('gestioncof.signals.messages')
+        patcher_messages.start()
+        self.addCleanup(patcher_messages.stop)
+
         # get some permissions
         perms = {
             'kfet.is_team': Permission.objects.get(codename='is_team'),
@@ -194,7 +200,8 @@ class OpenKfetConsumerTest(ChannelTestCase):
         OpenKfetConsumer.group_send('kfet.open.team', {'test': 'plop'})
         self.assertIsNone(c.receive())
 
-    def test_team_user(self):
+    @mock.patch('gestioncof.signals.messages')
+    def test_team_user(self, mock_messages):
         """Team user is added to kfet.open.team group."""
         # setup team user and its client
         t = User.objects.create_user('team', '', 'team')
@@ -224,6 +231,11 @@ class OpenKfetScenarioTest(ChannelTestCase):
     """OpenKfet functionnal tests suite."""
 
     def setUp(self):
+        # Need this (and here) because of '<client>.login' in setUp
+        patcher_messages = mock.patch('gestioncof.signals.messages')
+        patcher_messages.start()
+        self.addCleanup(patcher_messages.stop)
+
         # anonymous client (for views)
         self.c = Client()
         # anonymous client (for websockets)