starlingx/config: unit test exceptions & timeouts

[Davlet Panech]

Brief Description
-----------------

Unit tests in starlingx/config have problems:

1) They show many exceptions similar to:

2024-05-01 22:31:32.001464 | debian-bullseye | AttributeError: 'Semaphore' object has no attribute '_at_fork_reinit'
2024-05-01 22:31:32.001518 | debian-bullseye | Exception ignored in: <function _after_at_fork_child_reinit_locks at 0x7f1d55910790>
2024-05-01 22:31:32.001689 | debian-bullseye | Traceback (most recent call last):
2024-05-01 22:31:32.001715 | debian-bullseye | File "/usr/lib/python3.9/logging/__init__.py", line 251, in _after_at_fork_child_reinit_locks
2024-05-01 22:31:32.001734 | debian-bullseye | handler._at_fork_reinit()
2024-05-01 22:31:32.002157 | debian-bullseye | File "/usr/lib/python3.9/logging/__init__.py", line 890, in _at_fork_reinit
2024-05-01 22:31:32.002204 | debian-bullseye | self.lock._at_fork_reinit()
2024-05-01 22:31:32.002296 | debian-bullseye | File "/usr/lib/python3.9/threading.py", line 126, in _at_fork_reinit
2024-05-01 22:31:32.002316 | debian-bullseye | self._block._at_fork_reinit()

at least when executed by Zuul in Gerrit.

2) They take too long to run, and sometimes cause Zuul jobs to fail. This may be a side effect of problem 1.

Problem has been observed in Zuul. I don't know if it happens when you run these tests manually.

Example review: https://review.opendev.org/c/starlingx/config/+/915922
Failed pipeline: https://zuul.opendev.org/t/openstack/build/b7e405a4bbd34110bc28e83f79a6b219 - eventually succeeded when I forced it to re-run itself.

Severity
--------
Major

Steps to Reproduce
------------------
Problem observed in Zuul, see above

Expected Behavior
------------------
All Zuul tasks should succeed within 30 minutes

Actual Behavior
----------------
Zuul fails intermittently

Reproducibility
---------------
Intermittent

System Configuration
--------------------
N/A

Branch/Pull Time/Commit
-----------------------
master/2024-05-01

Last Pass
---------
N/A

Timestamp/Logs
--------------
See TIMED_OUT jobs in https://review.opendev.org/c/starlingx/config/+/915922 . I will also attach those logs separately to this LP.

Test Activity
-------------
[Sanity, Feature Testing, Regression Testing, Developer Testing, Evaluation, Other - Please specify]

Workaround
----------
Describe workaround if available