Unit tests crash on PySide6

[kristjanvalur]

Some internal issues with PySide6 cause the test suite to crash at random places.
PR #153 contains an attempted workaround, until PySide6 gets fixed upstream.

To repro:

uv virtualenv --python 3.13
uv pip install pyside6
uv run pytest --verbose

This will randomly crash on windows. If more complex tests are added later in the test suite the likelyhood of crashes increases.

[kristjanvalur]

I've done some further testing and it appers that this behaviour started happening with PySide6==6.8.0. Testing with earlier versions is just fine.
Modify the above code with uv pip install pyside6==6.8.0 to isolate to this particular version, and compare, e.g. , with 6.7.3 which is the previous release.

[kristjanvalur]

I've created an issue on the Qt project for this: https://bugreports.qt.io/browse/PYSIDE-3165

[kristjanvalur]

I think I have found the issue.
This has to do with race conditions during teardown of timer and notification objects. To combat this, these temporary and long running objects need to be parented to the app (or another long lived object).

I have created a pr which makes the use of these helpers robuster.

The clue to this is in running the unittests with the -s flag. uv run pytest -s.
You will see lots of warnings on stderr from QT, such as:

QObject::~QObject: Timers cannot be stopped from another thread

When timers aren't stopped properly, a race condition on timer delivery can occur. The timer event can be delivered to a deleted
object.

I believe the PR #158 is the right approach.

Btw, this largely resolves PySide. Although their bindings may be more fragile, not cleaning timers (and other objects) up properly , and ignoring the stderr warnings from the lib, is bound to cause issues.

[hosaka]

Thank you for looking into this, much appreciated! Fixed in #158.