浅谈Pytest中的warning处理

没有处理warning

我们写一个简单的测试

import pytest

def test_demo():

    import warnings

    warnings.warn('test warn',DeprecationWarning)

    assert True

if __name__ == '__main__':

    pytest.main(['-sv',__file__])

你运行的话会有如下提示

============================= test session starts =============================

platform win32 -- Python 3.9.6, pytest-7.1.2, pluggy-1.0.0 -- D:\Python39\python.exe

cachedir: .pytest_cache

metadata: ...

rootdir: D:\pythonProject\AutoTest\PytestTemp, configfile: pytest.ini

plugins: ...

collecting ... collected 1 item

test_demo.py::test_demo PASSED

============================== warnings summary ===============================

testCases/test_demo.py::test_demo

  test_demo.py:5: DeprecationWarning: test warn

    warnings.warn('test warn',DeprecationWarning)

-- Docs: https://docs.pytest.org/en/stable/how-to/capture-warnings.html

======================== 1 passed, 1 warning in 0.05s =========================

进程已结束，退出代码为 0

warning在pytest3.1之后会在执行期间捕获，初学者多见于mark漏了标记，可以参考浅谈Pytest中的marker

-W 命令行及处理

pytest提供了一个命令行参数-W

-W PYTHONWARNINGS, --pythonwarnings=PYTHONWARNINGS

   含义:　　set which warnings to report, see -W option of python itself.

python的-W

-W arg : warning control; arg is action:message:category:module:lineno  also PYTHONWARNINGS=arg

https://docs.python.org/3/library/warnings.html#warning-filter

关于格式说明

action is one of the following strings:

Value	Disposition
"default"	print the first occurrence of matching warnings for each location (module + line number) where the warning is issued
"error"	turn matching warnings into exceptions
"ignore"	never print matching warnings
"always"	always print matching warnings
"module"	print the first occurrence of matching warnings for each module where the warning is issued (regardless of line number)
"once"	print only the first occurrence of matching warnings, regardless of location

message is a string containing a regular expression that the start of the warning message must match, case-insensitively. In -W and PYTHONWARNINGS, message is a literal string that the start of the warning message must contain (case-insensitively), ignoring any whitespace at the start or end of message.

category is a class (a subclass of Warning) of which the warning category must be a subclass in order to match.

module is a string containing a regular expression that the start of the fully qualified module name must match, case-sensitively. In -W and PYTHONWARNINGS, module is a literal string that the fully qualified module name must be equal to (case-sensitively), ignoring any whitespace at the start or end of module.

lineno is an integer that the line number where the warning occurred must match, or 0 to match all line numbers.

---

增加命令行处理

# action:message:category:module:lineno   # 注意格式

-W error::DeprecationWarning  # 意思是看到DeprecationWarning就把它当做是一个error

================================== FAILURES ===================================

__________________________________ test_demo __________________________________

    def test_demo():

        import warnings

>       warnings.warn('test warn',DeprecationWarning)

E       DeprecationWarning: test warn

test_demo.py:5: DeprecationWarning

=========================== short test summary info ===========================

FAILED test_demo.py::test_demo - DeprecationWarning: test warn

============================== 1 failed in 0.09s ==============================

可以看到case变成了failed

---

换一下，改为ignore，case就PASSED了

pytest.main(['-sv','-W ignore::DeprecationWarning',__file__])

============================== 1 passed in 0.07s ==============================

等价的装饰器pytest.mark.filterwarnings

命令行的做法也可以等价到装饰器的写法，跟大多数的插件类似，命令行是针对所有的，装饰器是针对某个case的

@pytest.mark.filterwarnings('ignore::DeprecationWarning')  # 装饰在被测函数上即可

@pytest.mark.filterwarnings('error::DeprecationWarning')

等价的pytest.ini中的filterwarnings

你也可以这样写一个pytest.ini

[pytest]

filterwarnings:

    ignore::DeprecationWarning

或者这样

[pytest]

filterwarnings:

    error::DeprecationWarning

---

还可以这样

[pytest]

filterwarnings:

    error

    ignore::DeprecationWarning

这个意思是，所有的warning都被处理成error，但忽略DeprecationWarning。

注意：当警告与列表中的多个选项匹配时,将执行最后一个匹配选项的操作。

关于warning的其他

--disable-warnings命令行选项可以禁用warning summary

============================== warnings summary ===============================

testCases/test_demo.py::test_demo

  test_demo.py:5: DeprecationWarning: test warn

    warnings.warn('test warn',DeprecationWarning)

-- Docs: https://docs.pytest.org/en/stable/how-to/capture-warnings.html

上面的warning加了命令行之后就没了

命令行的解释

  --disable-warnings, --disable-pytest-warnings  ： disable warnings summary

---

还有一个命令行-pno:warnings，完全禁用警告捕获

pytest.main(['-sv','-pno:warnings',__file__])

实测-pno:warnings的pno要挨在一起，这有点...

命令行的解释

  -p name               early-load given plugin module name or

                        entry point (multi-allowed).

                        To avoid loading of plugins, use the

                        `no:` prefix, e.g. `no:doctest`.

如果你放在pytest.ini中的pno就可分可合(离谱)

[pytest]

addopts = -p no:warnings # -pno:warnings

浅谈Pytest中的warning处理的相关教程结束。