diff --git a/odoo/tests/common.py b/odoo/tests/common.py
index 287586d31a7..5944b8820dc 100644
--- a/odoo/tests/common.py
+++ b/odoo/tests/common.py
@@ -811,7 +811,7 @@ class ChromeBrowser():
         params = {kw:kwargs[kw] for kw in kwargs if kw in ['url', 'domain', 'path']}
         params.update({'name': name})
         _id = self._websocket_send('Network.deleteCookies', params=params)
-        return self._websocket_wait_id(_id) 
+        return self._websocket_wait_id(_id)
 
     def _wait_ready(self, ready_code, timeout=60):
         self._logger.info('Evaluate ready code "%s"', ready_code)
@@ -1000,6 +1000,9 @@ class HttpCase(TransactionCase):
     def authenticate(self, user, password):
         # stay non-authenticated
         if user is None:
+            if self.session:
+                odoo.http.root.session_store.delete(self.session)
+            self.browser.delete_cookie('session_id', domain=HOST)
             return
 
         db = get_db_name()