bug#24503: unstable test results (on hydra)

[Noam Postavsky]

Glenn Morris <rgm@gnu.org> writes:

> Tests that "randomly" fail, like the ones mentioned in this report, are
> a problem for downstream distributions that run "make check" and pay
> attention to the results (I sometimes think they pay more attention than
> Emacs does). They can waste their time investigating things that seem to
> be platform-specific just because they happen to fail once on a
> particular architecture.
>
> Eg
> https://bugs.debian.org/879020
>
> So we do a disservice to the wider community with these tests that
> sometimes fail. If they aren't good enough to be enabled on Emacs's own
> CI system, they probably aren't good enough full-stop, and should be
> disabled by default for everyone.

Hmm, I can't see any reason for these tests to fail in a
non-deterministic way.  This sounds like it could be a serious bug.  And
if happens on machines other than the Hydra ones, the bug is almost
certainly in Emacs.  I think we need to add some logging statements to
figure out what is going.  I will try to figure how to do that.