def test_quiet(self, httpbin, quiet_flags):
        env = MockEnvironment(
            stdin_isatty=True,
            stdout_isatty=True,
            devnull=io.BytesIO()
        )
        r = http(*quiet_flags, 'GET', httpbin.url + '/get', env=env)
        assert env.stdout is env.devnull
        assert env.stderr is env.devnull
        assert HTTP_OK in r.devnull
        assert r == ''
        assert r.stderr == ''