def test_no_telnet():
    parser = setup_parser()
    args = parser.parse_args(['backdoor', '0'])
    with patch('nameko.cli.backdoor.os') as mock_os:
        mock_os.system.return_value = -1
        with pytest.raises(CommandError) as exc:
            main(args)
    assert str(exc) in 'Could not find an installed telnet'
dataset/ETHPy150Open onefinestay/nameko/test/cli/test_backdoor.py/test_no_telnet/swapped operands of `in`