[Python-Dev] "make test" routinely fails to terminate

[Skip Montanaro]

On the 3.7 branch, "make test" routinely fails to terminate. (Pretty
vanilla Ubuntu 17.10 running on a Dell Laptop. Nothing esoteric at all)
Lately, it's been one of the multiprocessing tests. After a long while
(~2000 seconds), I kill it, then it complains many times about lack of a
valid_signals attribute in the signal module:

======================================================================
ERROR: test_remove_signal_handler_error2
(test.test_asyncio.test_unix_events.SelectorEventLoopSignalTests)
----------------------------------------------------------------------
Traceback (most recent call last):
   File "/home/skip/src/python/cpython/Lib/unittest/mock.py", line 1191, in
patched
     return func(*args, **keywargs)
   File
"/home/skip/src/python/cpython/Lib/test/test_asyncio/test_unix_events.py",
line 219, in test_remove_signal_handler_error2
     m_signal.valid_signals = signal.valid_signals
AttributeError: module 'signal' has no attribute 'valid_signals'

----------------------------------------------------------------------
Ran 1967 tests in 36.058s

FAILED (errors=362, skipped=11)
test test_asyncio failed
/home/skip/src/python/cpython/Lib/asyncio/base_events.py:605:
ResourceWarning: unclosed event loop <_UnixSelectorEventLoop running=False
closed=False debug=False>
   source=self)
Re-running test 'test_signal' in verbose mode

then reruns test_signal in verbose mode.

Earlier today, a run succeeded, so I'm guessing a race condition exists in
the test system. I recall encountering a similar problem a few weeks ago
and discovered this open ticket:

https://bugs.python.org/issue33099

Should I expect this as the normal behavior?

Skip