Warning integration breaks warnings.filterwarnings · Issue #2430 · pytest-dev/pytest (original) (raw)

SQLAlchemy CI is now broken due to the unconditional inclusion of pytest-warnings in py.test 3.1.0. I need at least to know how to disable this plugin entirely.

In our test suite we make use of the warnings filter internally in order to propagate our own warnings to errors. It seems like warnings.filter() is now non-functional when this plugin is installed.

Demo test case:

import warnings

class MyWarning(Warning):
    pass

warnings.filterwarnings("error", category=MyWarning)

class TestWarnings(object):
    def test_my_warning(self):
        try:
            warnings.warn(MyWarning("warn!"))
            assert False
        except MyWarning:
            assert True

with py.test 3.0.7:

$ py.test test_warning.py 
======================================================== test session starts ========================================================
platform linux2 -- Python 2.7.13, pytest-3.0.7, py-1.4.33, pluggy-0.4.0
rootdir: /home/classic/Desktop/tmp, inifile:
plugins: xdist-1.15.0, cov-2.4.0
collected 1 items 

test_warning.py .

===================================================== 1 passed in 0.01 seconds ======================================================

with py.test 3.1.0:

$ py.test test_warning.py 
======================================================== test session starts ========================================================
platform linux2 -- Python 2.7.13, pytest-3.1.0, py-1.4.33, pluggy-0.4.0
rootdir: /home/classic/Desktop/tmp, inifile:
plugins: xdist-1.15.0, cov-2.4.0
collected 1 items 

test_warning.py F

============================================================= FAILURES ==============================================================
___________________________________________________ TestWarnings.test_my_warning ____________________________________________________

self = <test_warning.TestWarnings object at 0x7fecb08a5290>

    def test_my_warning(self):
        try:
            warnings.warn(MyWarning("warn!"))
>           assert False
E           assert False

test_warning.py:12: AssertionError
========================================================= warnings summary ==========================================================
test_warning.py::TestWarnings::()::test_my_warning
  /home/classic/Desktop/tmp/test_warning.py:11: MyWarning: warn!
    warnings.warn(MyWarning("warn!"))

-- Docs: http://doc.pytest.org/en/latest/warnings.html
=============================================== 1 failed, 1 warnings in 0.03 seconds ================================================

I have tried everything I can think of with the new -W flag, disable-warnings, no luck.

Please advise on the correct options to allow Python stdlib warnings.filter() to work again, thanks!