如何为未捕获的异常处理程序编写单元测试

我有一个函数可以捕获uncaught例外情况，如下。有没有办法编写一个单元测试来执行uncaught_exception_handler()功能正常，但测试正常退出？

import logging

def config_logger():
    # logger setup here

def init_uncaught_exception_logger(logger):
    '''Setup an exception handler to log uncaught exceptions.

    This is typically called once per main executable.
    This function only exists to provide a logger context to the nested function.

    Args:
        logger (Logger): The logger object to log uncaught exceptions with.
    '''
    def uncaught_exception_handler(*exc_args):
        '''Log uncaught exceptions with logger.

        Args:
            exc_args: exception type, value, and traceback
        '''
        print("Triggered uncaught_exception_handler")
        logger.error("uncaught: {}: {}\n{}".format(*exc_args))

    sys.excepthook = uncaught_exception_handler

if __name__ == '__main__':
    LOGGER = config_logger()
    init_uncaught_exception_logger(LOGGER)
    raise Exception("This is an intentional uncaught exception")

最好不要测试您的函数是否因未捕获的异常而被调用，而是测试excepthook已安装，并且当您手动调用该函数时，该函数会执行正确的操作。这给了你很好的证据excepthook在实际使用中会表现正常。你会想要移动你的uncaught_exception_handler在外面init_uncaught_exception_logger这样您的测试就可以更轻松地访问它。

assert sys.excepthook is uncaught_exception_handler
with your_preferred_output_capture_mechanism:
    try:
        1/0
    except ZeroDivisionError:
        uncaught_exception_handler(*sys.exc_info())
assert_something_about_captured_output()

如果你想实际调用excepthook通过未捕获的异常，那么您需要启动一个子进程并检查其输出。这subprocess module https://docs.python.org/3/library/subprocess.html是实现这一目标的方法。