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Pytest下的Python测试运行无法正确捕获被调用的进程错误异常

doctest pytest subprocess exception python

Stefan · 技术社区 · 6 年前

在Pytest中运行Python doctests时,我目前面临一种奇怪的行为( py.test )。下面的代码片段突出显示了bevaviour。

医生们 确实通过 通过调用脚本时 python2.7 ./weirdpytestbehaviour_test.py 。
医生们 不通过 通过调用脚本时 py.test ./weirdpytestbehaviour_test.py --doctest-modules --tb=short 。
如果我改变陈述 except CalledProcessError as e: 进入 except Exception as e: 医生也会通过 py。测验 。

这看起来很无聊。测试对 CalledProcessError 异常类型。在中执行时,代码采用不同的求值路径是非常不直观的 py。测验 。我如何控制或调整这种行为?

#!/usr/bin/python
# coding=utf-8
# file: 'weirdpytestbehaviour_test.py'
from subprocess import check_output, CalledProcessError

def func(success):
    """The worker function.

    >>> func(success=True)
    >>> func(success=False)
    Ouch!
    Special treatment of this particular failure...
    """
    try:
        # Now invoke a subprocess
        if success:
            # Will always succeed and return with an exit code of 0
            check_output('echo "Hello!"; exit 0', shell=True)
        else:
            # Will always succeed and return with an exit code of 1
            check_output('echo "Ouch!"; exit 1', shell=True)

    # Does not catch the exception under pytest
    # 'except Exception as e:' would work as expected
    except CalledProcessError as e:
        print(e.output),
        if "Ouch!" in e.output:
            print("Special treatment of this particular failure...")
        else:
            raise

if __name__ == '__main__':
    import doctest
    doctest.testmod()

py的输出。失败情况下的测试(尝试捕获上面调用的进程错误)如下所示:

$ py.test ./weirdpytestbehaviour_test.py --doctest-modules --tb=short 
Test session starts (platform: linux2, Python 2.7.6, pytest 3.4.2, pytest-sugar 0.9.1)
[...]

007 The worker function.
008 
009     >>> func(success=True)
010 
011     >>> func(success=False)
UNEXPECTED EXCEPTION: CalledProcessError()
Traceback (most recent call last):

  File "/usr/lib/python2.7/doctest.py", line 1315, in __run
    compileflags, 1) in test.globs

  File "<doctest experiments.weirdpytestbehaviour_test.func[1]>", line 1, in <module>

  File "weirdpytestbehaviour_test.py", line 22, in func
    check_output('echo "Ouch!"; exit 1', shell=True)

  File "/usr/lib/python2.7/subprocess.py", line 573, in check_output
    raise CalledProcessError(retcode, cmd, output=output)

CalledProcessError: Command 'echo "Ouch!"; exit 1' returned non-zero exit status 1

weirdpytestbehaviour_test.py:11: UnexpectedException

weirdpytestbehaviour_test.py â¨¯                                                                                                                                                                                        100% ââââââââââ

Results (0.19s):
       1 failed
         - weirdpytestbehaviour_test.py:11 [doctest] weirdpytestbehaviour_test.func

1 回复 | 直到 6 年前

Stefan 6 年前

经过反复尝试,我不仅卸载并重新安装了pytest,而且还卸载并重新安装了我使用的插件,从而解决了这个问题。之后,它又开始工作了。

正在清理缓存( __pycache__ )没有效果。显然,pytest及其插件的安装有问题。