test_sleep() of test_eintr fails on VSTS/macOS.

select.select() sleeps 200 ms, the process is supposed to get a signal every 100 ms, but the test says that the signal handler was not called during the test. All tests pass, the issue seems to be specific to macOS.

Maybe select() cannot be interrupted by SIGALRM on macOS?

https://dev.azure.com/Python/cpython/_build/results?buildId=34604&view=logs

2018-11-26T12:51:16.6867210Z FAIL: test_sleep (__main__.TimeEINTRTest)
2018-11-26T12:51:16.6868140Z ----------------------------------------------------------------------
2018-11-26T12:51:16.6868300Z Traceback (most recent call last):
2018-11-26T12:51:16.6868450Z   File "/Users/vsts/agent/2.142.1/work/1/s/Lib/test/eintrdata/eintr_tester.py", line 73, in tearDown
2018-11-26T12:51:16.6868570Z     self.assertGreater(self.signals, 0)
2018-11-26T12:51:16.6869080Z AssertionError: 0 not greater than 0

2018-11-26T12:49:29.9119300Z os.uname: posix.uname_result(sysname='Darwin', nodename='Mac-329.local', release='17.7.0', version='Darwin Kernel Version 17.7.0: Thu Jun 21 22:53:14 PDT 2018; root:xnu-4570.71.2~1/RELEASE_X86_64', machine='x86_64')


I added the check (which fails) last week, ensure that the signal handler has been called at least once:

* bpo-35189
* commit aac1f81eef971876ba5b1673db9ce6620311c469

Some buildbots failing with this problem:

https://buildbot.python.org/all/#/builders/145/builds/849

I will investigate with MacOS Mojave this week.

I'm unable to reproduce the issue using "./python.exe Lib/test/eintrdata/eintr_tester.py -v SelectEINTRTest.test_select" on macOS 10.13.6.

New changeset 2956bffbc00127af65f69e04d7979021a21d1288 by Victor Stinner in branch 'master':
bpo-35189, bpo-35316: Make test_eintr less strict (GH-10782)
https://github.com/python/cpython/commit/2956bffbc00127af65f69e04d7979021a21d1288

New changeset 2fa5b2ac4485c5c9083b4b0459dd9b691daaea28 by Miss Islington (bot) in branch '3.7':
bpo-35189, bpo-35316: Make test_eintr less strict (GH-10782)
https://github.com/python/cpython/commit/2fa5b2ac4485c5c9083b4b0459dd9b691daaea28

New changeset 833a7067a4d5621d024511d9166db7331c4650c9 by Miss Islington (bot) in branch '3.6':
bpo-35189, bpo-35316: Make test_eintr less strict (GH-10782)
https://github.com/python/cpython/commit/833a7067a4d5621d024511d9166db7331c4650c9

> I will investigate with MacOS Mojave this week.

Ok, so I leave the issue open.

I close the issue.

@Pablo: You are free to continue to investigate why sometimes test_sleep() is not interrupted by any signal.

Note: I just fixed another test_eintr bug on macOS, bpo-35363.