遵循 Head First Python 2nd edition 时出现 Pytest-pep8 问题答案

【问题标题】：Pytest-pep8 problem while following Head First Python 2nd edition遵循 Head First Python 2nd edition 时出现 Pytest-pep8 问题
【发布时间】：2019-12-29 21:20:54
【问题描述】：

我一直在关注 Head First Python 2nd Edition，在第 4 章中，演示了 pep8 合规性测试。尽管与书中的代码相同，但我的输出却不同。

测试代码很简单：

def search4vowels(phrase: str) -> set:
    """Return vowels found in supplied phrase."""
    vowels = set('aeiou')
    return vowels.intersection(set(phrase))


def search4letters(phrase: str, letters: str='aeiou') -> set:
    """Return a set of 'letters' found in 'phrase'."""
    return set(letters).intersection(set(phrase))

我尝试按照书中所示进行测试，并得到了以下输出：

λ py.test.exe --pep8 vsearch.py
c:\users\gx\appdata\local\programs\python\python37-32\lib\site-packages\pep8.py:110: FutureWarning: Possible nested set at position 1
  EXTRANEOUS_WHITESPACE_REGEX = re.compile(r'[[({] | []}),;:]')
============================= test session starts =============================
platform win32 -- Python 3.7.4, pytest-5.1.1, py-1.8.0, pluggy-0.12.0
rootdir: C:\Users\gx\Desktop\H.F. Python\mymodules
plugins: pep8-1.0.6
collected 1 item

vsearch.py .                                                             [100%]

============================== warnings summary ===============================
c:\users\gx\appdata\local\programs\python\python37-32\lib\site-packages\_pytest\mark\structures.py:324
  c:\users\gx\appdata\local\programs\python\python37-32\lib\site-packages\_pytest\mark\structures.py:324:
PytestUnknownMarkWarning: Unknown pytest.mark.pep8 - is this a typo?
You can register custom marks to avoid this warning - for details, see https://docs.pytest.org/en/latest/mark.html
    PytestUnknownMarkWarning,

-- Docs: https://docs.pytest.org/en/latest/warnings.html
======================== 1 passed, 1 warnings in 0.04s ========================

（我稍微修改了空格以使其更具可读性）

在书中没有发生这样的事情。在这样做之前，我已经全新安装了 pytest 和 pytest-pep8，如书中所示。

是什么原因造成的？

【问题讨论】：

标签： python pytest pep8

【解决方案1】：

这似乎是一个已知问题：#23。一种解决方法是在pytest.ini 中注册pep8 标记：

[pytest]
markers =
    pep8: workaround for https://bitbucket.org/pytest-dev/pytest-pep8/issues/23/

或以编程方式在conftest.py 中注册它：

def pytest_configure(config):
    config.addinivalue_line(
        'markers', 'pep8: workaround for https://bitbucket.org/pytest-dev/pytest-pep8/issues/23/'
    )

【讨论】：