Many pytest users would like a concise way to either suppress warnings, or convert them to errors [1]. The current best approach is:

    with warnings.catch_warnings():
        warnings.simplefilter("ignore")  # or "error"

but even this becomes tediously verbose when repeated in hundreds of tests (which I suspect is responsible for many misuses of pytest.raises()). Since these two functions take disjoint arguments [2], I propose allowing catch_warnings() to accept arguments for simplefilter() and forward them on:

    with warnings.catch_warnings("ignore"):  # or "error"

I have a quick implementation at [3] which I can finish if the idea is acceptable. Although I don't have a concrete use-case for more than the 'action' and 'category' arguments, forwarding all rather than some makes the semantics very simple.

I'd emphasize again that this is very much a convenience-focussed change: I estimate that 95% of all uses will pass only action="error" or action="ignore". Supporting a concise and simple interface for this seems worth the small complication to the design of the warnings module.

[1] see e.g. pytest-dev/pytest#9404 for a long thread
[2] unlike filterwarnings(), which has a module= argument which would collide with catch_warnings()
[3] main...Zac-HD:zac-hd/one-line-catch-warnings