test_file_descriptors_dont_leak flaky

[gjoseph92]

On macOS, 3.8: https://github.com/dask/distributed/pull/4925/checks?check_run_id=2888102705#step:10:2325

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

s = <Scheduler: "tcp://127.0.0.1:60661" workers: 0 cores: 0, tasks: 0>

    @pytest.mark.skipif(
        sys.platform.startswith("win"), reason="file descriptors not really a thing"
    )
    @gen_cluster(nthreads=[])
    async def test_file_descriptors_dont_leak(s):
        psutil = pytest.importorskip("psutil")
        proc = psutil.Process()
        before = proc.num_fds()
    
        w = await Worker(s.address)
        await w.close()
    
        during = proc.num_fds()
    
        start = time()
        while proc.num_fds() > before:
            await asyncio.sleep(0.01)
>           assert time() < start + 5
E           assert 1624391425.688429 < (1624391420.652608 + 5)
E            +  where 1624391425.688429 = time()

distributed/tests/test_scheduler.py:677: AssertionError

Why doesn't during = proc.num_fds() come before await w.close()?

[jrbourbeau]

Why doesn't during = proc.num_fds() come before await w.close()?

I'm not sure, but it looks like during isn't actually used in this test. We can probably remove it altogether

[fjetter]

FWIW, I ran into some leaky file descriptors and could trace this back to our connectionpool, see #4951
but on another test

[GenevieveBuckley]

Do you think this might also be related? #4045

[fjetter]

No failure in the last 30days. Closing