Yield test deprecation warning spams too much

[pv]

While working on scipy/scipy#7572 I noticed that pytest emits the "yield tests are deprecated, and scheduled to be removed in pytest 4.0" warning for each generated test, not per each test generator. (And for scipy, this means the message is printed 15652 times :) -- of course we'll eventually plan to refactor them completely away, but that takes some time.)

There are workarounds such as --disable-warnings and tagging | uniq to the end, but it would be nice if this was fixed to be less spammy on the pytest end.

As far as I understand, there's no way to disable this deprecation warning in pytest.ini without also disabling the whole warning capture mechanism (which is what --disable-pytest-warnings et al seem to do)?

Minimal repro:

# python -mpytest test_foo.py
def test_foo():
    for k in range(10000):
        yield lambda x: None, k

``` plat: Linux $ python --version Python 2.7.13 $ pip list pip (9.0.1) py (1.4.34) pytest (3.1.3) setuptools (36.0.1) wheel (0.29.0) ```

[nicoddemus]

Agreed on issuing the warning only once per generator.

To suppress those warnings you can add this to your pytest.ini:

[pytest]
filterwarnings =
    ignore:.*yield tests are deprecated.*

[pv]

@nicoddemus: adding that to pytest.ini doesn't silence these warnings for me, in the example case given above.

[nicoddemus]

Hmm yeah I didn't test it, sorry. Those parameters are passed to warnings.filterwarnings, so if you can find how to silence them using warnings.filterwarnings you should be able to set that in your pytest.ini.

[pv]

This deprecation warning seems to be emitted at _pytest/python.py:618 directly by self.config.warn so it doesn't go through the Python warning mechanism. (Maybe changing it to warnings.warn would be enough?) Or just dedent by 4 spaces?

[nicoddemus]

Oh you are right, sorry about that. Indeed we would have to change it to raise an actual warning.

[nicoddemus]

xref: #1043

[pv]

I'll submit a pull request removing the four spaces in a moment :)
Maybe it makes sense to emit it only once per each generator function.

[nicoddemus]

Fixed in #2563