Add missing with_statement import

trytond/tests/test_tryton.py

@@ -2,7 +2,7 @@
 # -*- coding: utf-8 -*-
 #This file is part of Tryton.  The COPYRIGHT file at the top level of
 #this repository contains the full copyright notices and license terms.
-
+from __future__ import with_statement
 import logging
 logging.basicConfig(level=logging.ERROR)
 import sys, os