test that matplotlib event loop integration is responsive

[minrk]

also fixes %matplotlib osx which gets converted to macosx on its way through matplotlib and back

This should hopefully be the regression test for #1458

[minrk]

all the matplotlib tests are passing on mac and windows, need to figure out why linux isn't enabling the event loops

[ccordoba12]

need to figure out why linux isn't enabling the event loops

Perhaps you need to run that test with xvfb?

[minrk]

Perhaps you need to run that test with xvfb?

Probably right, looking at that.

[ianthomas23]

Changes look good to me, and tests pass locally on both macos and linux. I don't understand the CI failures but I assume they are related to xvfb? Matplotlib itself pip installs pytest-xvfb which might be worth a try as with it installed pytest automatically uses xvfb without having to set the PRE_TEST stuff.

[minrk]

with xvfb, the tests are hanging after embed_kernel, which makes me think it might be during setup of test_eventloops

[ianthomas23]

Is it worth just disabling the reliably-failing test_matplotlib_eventloops.py on qt5/python3.14 so we can merge and come back to this later?

[minrk]

Yes, I think so. Sorry I couldn't figure out how to get these more reliable. They pass 100% every time I test locally, so I think it's something about how slow ci environments are

[minrk]

I give up, I just skipped the tests altogether on CI. They are too flaky. I'm sure there's some race somewhere, perhaps in where the kernel runs the cell activating the event loop and then enters the eventloop mode, maybe a message can get dropped or stuck waiting somewhere? It could be a real bug, but I don't want to hold up the 7.1 release anymore, and this does have the %matplotlib osx fix that should get in there.

But these tests pass 100% for me locally, so I at least know that they verify %matplotlib osx work, so I don't want to delete them. I'll come back and try to track down the problem another time with less pressure.

[ianthomas23]

Thanks @minrk, I completely agree. Approving and merging this with CI disabled so that I can proceed with the 7.1.0 release and we can circle back to this later.