python - 如何在导入 pytest conftest.py 之前设置配置？

Question

我有myprj项目，文件如下。

$ tree myprj/
myprj/
├── prj
│   ├── __init__.py
│   ├── config.py
│   ├── my_logger.py
│   ├── my_module.py
│   └── tests
│       ├── __init__.py
│       ├── conftest.py
│       └── unit
│           ├── __init__.py
│           └── test_my_module.py
├── setup.py
└── tox.ini

config.py

LOG_FILE='/path/exists/on/production/prj.log'

my_logger.py

from prj import config
import logging

class MyLogger():
    def __init__(self):
        self.setup_logger()

    def setup_logger(self):
        logFilename = config.LOG_FILE

        file_hdlr = logging.FileHandler(logFilename)

my_module.py

from prj import my_logger

myLogger = my_logger.MyLogger()


def my_method():
    return 1

test_my_module.py

from prj import my_module

def test_my_method():
    assert 1 == my_module.my_method()

setup.py

from setuptools import setup

setup(name="Tox Testing")

tox.ini

[tox]
envlist = py35

[testenv]
deps=pytest
commands=py.test

当我运行 tox 时，它失败并显示日志文件的路径不存在。

GLOB sdist-make: /private/tmp/myprj/setup.py
py35 inst-nodeps: /private/tmp/myprj/.tox/dist/Tox Testing-0.0.0.zip
py35 installed: attrs==17.4.0,pluggy==0.6.0,py==1.5.2,pytest==3.3.2,six==1.11.0,Tox-Testing==0.0.0
py35 runtests: PYTHONHASHSEED='2231398989'
py35 runtests: commands[0] | py.test
========================================================================================================= test session starts =========================================================================================================
platform darwin -- Python 3.5.2, pytest-3.3.2, py-1.5.2, pluggy-0.6.0
rootdir: /private/tmp/myprj, inifile:
collected 0 items / 1 errors

=============================================================================================================== ERRORS ================================================================================================================
__________________________________________________________________________________________ ERROR collecting prj/tests/unit/test_my_module.py __________________________________________________________________________________________
prj/tests/unit/test_my_module.py:1: in <module>
    from prj import my_module
prj/my_module.py:3: in <module>
    myLogger = my_logger.MyLogger()
prj/my_logger.py:6: in __init__
    self.setup_logger()
prj/my_logger.py:11: in setup_logger
    file_hdlr = logging.FileHandler(logFilename)
/Users/nile2691/.pyenv/versions/3.5.2/lib/python3.5/logging/__init__.py:1008: in __init__
    StreamHandler.__init__(self, self._open())
/Users/nile2691/.pyenv/versions/3.5.2/lib/python3.5/logging/__init__.py:1037: in _open
    return open(self.baseFilename, self.mode, encoding=self.encoding)
E   FileNotFoundError: [Errno 2] No such file or directory: '/path/exists/on/production/prj.log'
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Interrupted: 1 errors during collection !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
======================================================================================================= 1 error in 0.36 seconds =======================================================================================================
ERROR: InvocationError: '/private/tmp/myprj/.tox/py35/bin/py.test'
_______________________________________________________________________________________________________________ summary _______________________________________________________________________________________________________________
ERROR:   py35: commands failed

我明白了，日志文件路径在我的本地系统中不存在，并且出现错误。

我尝试使用 conftest.py 固定装置在 config.py 中设置 LOG_FILE 变量。

conftest.py

import pytest
from prj import config


@pytest.fixture(scope="session", autouse=True)
def set_config():
    config.LOG_FILE = '/tmp/prj.log'

但它仍然返回相同的错误。如果我能够在开始测试执行之前调用某些内容，例如 py.test 的第一个执行步骤，那么我可以设置 LOG_FILE 并且它不会引发错误.

Answer 1

在 my_module.py 的全局范围内，您创建一个实例 my_logger.MyLogger() ，并在 MyLogger.__init__ 中记录处理程序设置。

您的问题是在导入时设置日志处理程序的反模式。不要这样做。

对于应用程序，应在运行时配置日志处理程序(通过 main() 或其他方式完成)。对于库，根本不应该配置日志记录处理程序( possibly adding a NullHandler 除外) - 由库的用户决定他们希望如何配置处理程序。

请注意，pytest 不需要已经配置日志处理程序来测试记录的记录并对日志事件做出断言 - caplog 装置将插入自己的处理程序以捕获日志记录事件，因此即使未配置日志系统也可以使用它。