Flaky `test_quiet_client_close`

[gjoseph92]

This hasn't actually failed yet on the test report, but I know it could like it did here: #6504 (comment)

This is caused by #6390 in fallout from #6361.

    def test_quiet_client_close(loop):
        with captured_logger(logging.getLogger("distributed")) as logger:
            with Client(
                loop=loop,
                processes=False,
                dashboard_address=":0",
                threads_per_worker=4,
            ) as c:
                futures = c.map(slowinc, range(1000), delay=0.01)
                sleep(0.200)  # stop part-way
            sleep(0.1)  # let things settle
    
            out = logger.getvalue()
            lines = out.strip().split("\n")
            assert len(lines) <= 2
            for line in lines:
>               assert (
                    not line
                    or "Reconnecting" in line
                    or "garbage" in line
                    or set(line) == {"-"}
                ), line
E               AssertionError: Received heartbeat from unregistered worker 'inproc://10.213.1.205/15971/24'.

I think we can just swap reconnecting with unregistered worker in the acceptable output. It's not great that that happens, but the only fix for it is #6390. So in the interim, we can just accept that it may happen.

[gjoseph92]

@graingert saw this again with a slightly different error. You can have much more than 2 lines when the heartbeat fails :)

___________________________ test_quiet_client_close ____________________________

loop = <tornado.platform.asyncio.AsyncIOMainLoop object at 0x13e44e110>

    def test_quiet_client_close(loop):
        with captured_logger(logging.getLogger("distributed")) as logger:
            with Client(
                loop=loop,
                processes=False,
                dashboard_address=":0",
                threads_per_worker=4,
            ) as c:
                futures = c.map(slowinc, range(1000), delay=0.01)
                sleep(0.200)  # stop part-way
            sleep(0.1)  # let things settle
    
            out = logger.getvalue()
            lines = out.strip().split("\n")
>           assert len(lines) <= 2
E           assert 16 <= 2
E            +  where 16 = len(["Received heartbeat from unregistered worker 'inproc://10.79.8.226/15050/24'.", 'Heartbeat to scheduler failed', 'Traceback (most recent call last):', '  File "/Users/runner/work/distributed/distributed/distributed/worker.py", line 1159, in heartbeat', '    response = await retry_operation(', '  File "/Users/runner/work/distributed/distributed/distributed/utils_comm.py", line 383, in retry_operation', ...])

distributed/tests/test_client.py:4934: AssertionError

https://github.com/dask/distributed/runs/7672977739?check_suite_focus=true#step:11:1346