'make check-acceptance' failing on s390 tests?

[Peter Maydell]

Hi; is anybody else seeing 'make check-acceptance' fail on some of
the s390 tests?

 (009/183) tests/avocado/boot_linux.py:BootLinuxS390X.test_s390_ccw_virtio_tcg:
INTERRUPTED: Test interrupted by SIGTERM\nRunner error occurred:
Timeout reached\nOriginal status: ERROR\n{'name':
'009-tests/avocado/boot_linux.py:BootLinuxS390X.test_s390_ccw_virtio_tcg',
'logdir': 
'/mnt/nvmedisk/linaro/qemu-from-laptop/qemu/build/clang/tests/results/j...
(900.20 s)


 (090/183) 
tests/avocado/machine_s390_ccw_virtio.py:S390CCWVirtioMachine.test_s390x_fedora:
FAIL: b'1280 800\n' != b'1024 768\n' (26.79 s)


I've cc'd Daniel because the 090 at least looks like a resolution
baked into the test case, and commit de72c4b7c that went in
last month changed the EDID reported resolution from 1024x768
to 1280x800.

Not sure about the timeout on the boot test: the avocado log
shows it booting at least as far as
"Kernel 5.3.7-301.fc31.s390x on an s390x (ttysclp0)"
and then there's no further output until the timeout.
Unfortunately the avocado log doesn't seem to include useful
information like "this is the string we were waiting to see", so
I'm not sure exactly what's gone wrong there.

(I continue to find the Avocado tests rather opaque: when you
get a series of green OK's that's fine, but when you get a failure
it's often non-obvious why it failed or how to do simple things
like "rerun just that one failed test" or "run the failing command,
interactively on the command line".)

The 090 failure didn't cause the merge to be rejected because
in commit 333168efe5c8 we disabled both these tests when
running on GitLab.

Suggestion: we should either disable tests entirely (except
for manual "I want to run this known-flaky test") or not at
all, rather than disabling them only on GitLab. If I'm running
'make check-acceptance' locally I don't want to be distracted
by tests we know to be dodgy, any more than if I were running
the CI on GitLab.

thanks
-- PMM