Compatability with pytest pytest-xdist==1.30.0

[therefromhere]

FYI I think there's a compatibility issue with pytest-xdist==1.30.0, see pytest-dev/pytest-xdist#472

[adamchainz]

We don't currently test with xdist, if you are working on this I think it'd be good to have some tests here using it.

[adamchainz]

Thanks @thedrow . Will close this issue then.

[nodakai]

No, the issue is still there (I'm not saying pytest-randomly has to do anything for this issue but just for the sake of recoding...)

test/test_0.py

def test_a(): pass

test/test_1.py

def test_b(): pass

$ while pytest -d --tx 2*popen test; do sleep 1; done
(after several successes...)
========================================== test session starts ===========================================
platform linux -- Python 3.7.6, pytest-5.4.1, py-1.8.1, pluggy-0.13.1
Using --randomly-seed=1586915652
rootdir: /home/kai/tst
plugins: forked-1.1.3, randomly-3.2.1, xdist-1.31.0
gw0 [2] / gw1 [2]
collecting 0 items / 1 error                                                                             
================================================= ERRORS =================================================
__________________________________________ ERROR collecting gw1 __________________________________________
Different tests were collected between gw0 and gw1. The difference is:
--- gw0

+++ gw1

@@ -1,2 +1,2 @@

+test/test_0.py::test_a
 test/test_1.py::test_b
-test/test_0.py::test_a
======================================== short test summary info =========================================
ERROR gw1
============================================ 1 error in 0.37s ============================================

There's some indeterminacy here

[adamchainz]

Thanks for the example @nodakai . With that I was able to figure out what the problem was - the workers would sometimes not share the same default seed, since it's based on int(time.time()) and sometimes workers would start across the second boundary. This is, of course, a random error 😂

Fixed in #245 and released in version 3.3.0 ! 🎲🎉

[therefromhere]

Awesome!

[fermezz]

@adamchainz would you guys be open to a contribution backporting this fix into the 1.2.x branch? Since pytest-dev/pytest#6870 was merged, now pytest-randomly on version 1.2.x –the one compatible with Python2– is incompatible with pytest version >=4.6.10

[adamchainz]

I don't work with Python 2.7 more (at least, for free). If you want a backport please fork, cherry-pick the commit, and pip install from your repo.