Python3.x 在 pytest 中，如何测试 sys.exit('some error message')

我是巨 Python 和巨 Python 的初学者.我有一个函数，我正在try 用Pytest测试它的异常部分:

def read_data(args) -> tuple[Polyline, str]:
    parsed_args = input_parsing_1(args)
    try:
        with open(parsed_args.f) as f_input:
            reader = csv.reader(f_input)
            polyline = fill_poly_with_data(reader)
    except FileNotFoundError as e:
        sys.exit('Invalid input file \n')
    else:
        return (polyline, parsed_args.f)

我想测试是否引发了异常，以及错误消息是否与我在上面的代码中输入的消息匹配.

My attempts个

@patch('project.open')
def test_read_data_error_SE(mock_open):
    mock_open.side_effect = SystemExit
    with pytest.raises(SystemExit):
        assert read_data(['-f', ''])

@patch('project.open')
def test_read_data_error_FNFE2(mock_open):
    mock_open.side_effect = FileNotFoundError
    with pytest.raises(SystemExit):
        with pytest.raises(FileNotFoundError):
            assert read_data(['-f', 'cos'])

上述测试运行良好.

我还希望断言sys.exit消息是否与'Invalid input file \n'匹配.我试过了:

@patch('project.open')
def test_read_data_error_SE1(mock_open):
    mock_open.side_effect = SystemExit
    with pytest.raises(SystemExit, match='Invalid input file'):
        assert read_data(['-f', ''])

@patch('project.open')
def test_read_data_error_SE2(mock_open):
    mock_open.side_effect = SystemExit
    with pytest.raises(SystemExit) as e:
        assert read_data(['-f', ''])
    assert 'Invalid input file' in str(e.value)

但这些测试都失败了:

===================================================== short test summary info ======================================================
FAILED test_project.py::test_read_data_error_SE1 - AssertionError: Regex pattern did not match.
FAILED test_project.py::test_read_data_error_SE2 - AssertionError: assert 'Invalid input file' in ''

我在Stackoverflow上看到了一些帖子，比如: Verify the error code or message from SystemExit in pytest个

How to properly assert that an exception gets raised in pytest?个

Catch SystemExit message with Pytest个

但他们似乎都没有回答我的问题.

My questions:个

我测试过的消息‘INVALID INPUT FILE’似乎正在与空字符串‘’匹配？为什么？如何正确捕获和断言sys.exit("一些错误消息")？