Check if any tests raise a deprecation warning with pytest

Question

I am using pytest to run tests in a Python package, and I would like to know if any of the code that is executed as part of the tests is raising deprecation warnings (when all tests are passing). Does anyone know of a way to do this?

Answer 1

The code

import warnings
warnings.simplefilter("error")

will turn (all) warnings into errors, which may help.

Alternatively, you can get a list of generated warnings with

import warnings

with warnings.catch_warnings(record=True) as w:
    warnings.warn("deprecated", DeprecationWarning)
    print(w)

#>>> [<warnings.WarningMessage object at 0x7fee80484f50>]

and then assert on that list.

Answer 2

Starting with pytest 3.1, warnings are automatically displayed at the end of the session: see https://docs.pytest.org/en/latest/warnings.html