def test_invalid(self):
        with self.assertRaises(colander.Invalid) as cm:
            swv.iso8601Validator(self.node, 'May 14 2013 10:11:12')

        self.assertEqual(cm.exception.msg, 'Invalid date')
 def test_valid(self):
     swv.iso8601Validator(self.node, '2013-05-14T10:11:12Z')