Investigate integration test termination

[dimaqq]

Description

When failing and flakey tests are disabled, the integration test job/tox doesn't terminate...

Timing of the integration test run:

-3m job setup
0.0 tox started
0.0 first skipped tests
0.0 first passed tests
 5m 25% tests done
14m 50% tests done
19m 75% tests done
30m 97% tests done

[long gap here]

2h+ still waiting at 97% tests done ...

Urgency

Casually reporting

Python-libjuju version

3.5.2

Juju version

3.4/stable

[dimaqq]

Sample run: https://github.com/juju/python-libjuju/actions/runs/11209028274/job/31153637887?pr=1120

[dimaqq]

Last completed tests by worker:

[gw0] [ 79%] SKIPPED tests/integration/test_model.py::test_detach_storage
[gw1] [ 97%] PASSED tests/integration/test_unit.py::test_ssh
[gw2] [ 96%] PASSED tests/integration/test_unit.py::test_unit_introspect
[gw3] [ 95%] PASSED tests/integration/test_unit.py::test_unit_public_address

may not be informative, as the test that didn't finish is probably not reported yet.

[james-garner-canonical]

We should probably force tests to run single threaded in a deterministic order