How to use the blackhole.daemon.Daemon function in blackhole

def test_delete_pid_exit():
    pfile = create_file("test.pid", 123)
    with mock.patch("os.getpid", return_value=123), mock.patch(
        "atexit.register"
    ):
        daemon = Daemon(pfile)
        assert daemon.pid == 123
        daemon._exit()
        assert daemon.pid is None

def test_set_pid_valid_path():
    pid = os.path.join(os.getcwd(), "fake.pid")
    with mock.patch("os.getpid", return_value=666), mock.patch(
        "atexit.register"
    ):
        daemon = Daemon(pid)
        assert daemon.pidfile == pid
        assert daemon.pid == 666

def test_delete_pid():
    pfile = create_file("test.pid", 123)
    with mock.patch("os.getpid", return_value=123), mock.patch(
        "atexit.register"
    ):
        daemon = Daemon(pfile)
        assert daemon.pid == 123
        del daemon.pid
        assert daemon.pid is None

def test_fork_error():
    pfile = create_file("test.pid", 123)
    with mock.patch("atexit.register"):
        daemon = Daemon(pfile)
    with mock.patch(
        "os.fork", side_effect=OSError
    ) as mock_fork, pytest.raises(DaemonException):
        daemon.fork()
    assert mock_fork.called is True

def test_fork():
    pfile = create_file("test.pid", 123)
    with mock.patch("atexit.register"):
        daemon = Daemon(pfile)
    with mock.patch("os.fork", return_value=9999) as mock_fork, mock.patch(
        "os._exit"
    ) as mock_exit:
        daemon.fork()
    assert mock_fork.called is True
    assert mock_exit.called is True

def test_delete_pid_no_exists():
    pfile = create_file("test.pid", 123)
    daemon = Daemon(pfile)
    with mock.patch("os.remove") as mock_rm, mock.patch(
        "atexit.register"
    ), mock.patch("os.path.exists", return_value=False):
        del daemon.pid
    assert mock_rm.called is False

with mock.patch(
            "builtins.open", side_effect=FileNotFoundError
        ), mock.patch("atexit.register"), pytest.raises(DaemonException):
            Daemon("/fake/path.pid")
        with mock.patch("builtins.open", side_effect=IOError), mock.patch(
            "atexit.register"
        ), pytest.raises(DaemonException):
            Daemon("/fake/path.pid")
        with mock.patch(
            "builtins.open", side_effect=PermissionError
        ), mock.patch("atexit.register"), pytest.raises(DaemonException):
            Daemon("/fake/path.pid")
        with mock.patch("builtins.open", side_effect=OSError), mock.patch(
            "atexit.register"
        ), pytest.raises(DaemonException):
            Daemon("/fake/path.pid")

def test_instantiated_but_not_daemonised():
    pid = os.path.join(os.getcwd(), "fake.pid")
    with mock.patch("os.getpid", return_value=666):
        daemon = Daemon(pid)
        assert daemon.pidfile == pid
        assert daemon.pid == 666

def test_daemonise():
    pfile = create_file("test.pid", 123)
    with mock.patch("blackhole.daemon.Daemon.fork") as mock_fork, mock.patch(
        "os.chdir"
    ) as mock_chdir, mock.patch("os.setsid") as mock_setsid, mock.patch(
        "os.umask"
    ) as mock_umask, mock.patch(
        "atexit.register"
    ) as mock_atexit, mock.patch(
        "os.getpid", return_value=123
    ):
        daemon = Daemon(pfile)
        daemon.daemonize()
    assert mock_fork.called is True
    assert mock_chdir.called is True
    assert mock_setsid.called is True
    assert mock_umask.called is True
    assert mock_atexit.called is True

:raises SystemExit: Exit code :py:obj:`os.EX_USAGE` when a configuration
                        error occurs, :py:obj:`os.EX_NOPERM` when a permission
                        error occurs or :py:obj:`os.EX_OK` when the program
                        exits cleanly.
    """
    args = parse_cmd_args(sys.argv[1:])
    configure_logs(args)
    logger = logging.getLogger("blackhole")
    if args.test:
        config_test(args)
    try:
        config = Config(args.config_file).load().test()
        config.args = args
        warn_options(config)
        daemon = Daemon(config.pidfile)
        supervisor = Supervisor()
        pid_permissions()
        setgid()
        setuid()
    except (ConfigException, DaemonException) as err:
        logger.critical(err)
        raise SystemExit(os.EX_USAGE)
    except BlackholeRuntimeException as err:
        logger.critical(err)
        raise SystemExit(os.EX_NOPERM)
    if args.background:
        try:
            daemon.daemonize()
        except DaemonException as err:
            supervisor.close_socks()
            logger.critical(err)