'Run the client with output streams mocked out'

def _call_no_clientmock(self, args, stdout=None):

    args = (self.standard_args + args)
    toy_stdout = (stdout if stdout else six.StringIO())
    with mock.patch('certbot.main.sys.stdout', new=toy_stdout):
        with mock.patch('certbot.main.sys.stderr') as stderr:
            ret = main.main(args[:])
    return (ret, toy_stdout, stderr)
