gh-106368: Increase test coverage for Argument Clinic

[erlend-aasland]

• Issue: Increase Argument Clinic test coverage #106368

[erlend-aasland]

With this, we're pretty good covered (above 90%). AFAICS, converters, return converters, and most parser code has been tested. Most of what's missing is various error paths.

I suggest we close the linked issue after landing this.

[sobolevn]

Thanks! 👍

[AlexWaygood]

The .py tests LGTM! Nikita's almost certainly a better reviewer for the functional tests :)

[erlend-aasland]

The .py tests LGTM! Nikita's almost certainly a better reviewer for the functional tests :)

Thanks for the review; Nikita gave a thumbs up for the functional tests earlier, so I'll enable auto-merge 🚀

[miss-islington]

Thanks @erlend-aasland for the PR 🌮🎉.. I'm working now to backport this PR to: 3.11, 3.12.
🐍🍒⛏🤖

[miss-islington]

Sorry, @erlend-aasland, I could not cleanly backport this to 3.12 due to a conflict.
Please backport using cherry_picker on command line.
cherry_picker b9c9a36c2f2edc11b9c27eb7c5810919d9da9767 3.12

[miss-islington]

Sorry, @erlend-aasland, I could not cleanly backport this to 3.11 due to a conflict.
Please backport using cherry_picker on command line.
cherry_picker b9c9a36c2f2edc11b9c27eb7c5810919d9da9767 3.11

[picnixz]

3.11 and 3.12 never got their backports but I'm removing the labels (I'm going through PRs to see if we did not forgot a backport) (not sure if you want to backport this on 3.12)