Add 3rd party tests for litestar

[provinzkraut]

Add Litestar to the 3rd party tests.

The package relies significantly on runtime type inspections (and therefore typing-extensions 🙂), and we've been made aware that it was also affected by #560.
The issue had first been raised as a Debian bug report and was forwarded to us; An early(er) warning could have been useful to avoid this downstream issue.

The tests themselves don't take too long (~30-60 seconds), as we only need to run a subset of our test suite.

[AlexWaygood]

These tests are nice and fast, the 3rd-party CI only runs once a night, and litestar is a very popular library -- so this seems pretty reasonable to me!

Each new library we add to this workflow adds a certain maintenance burden for us, as they do fail reasonably often due to changes beyond our control. I think this one meets the cost-benefit threshhold for it to be worth it, though.

[AlexWaygood]

The issue had first been raised as a Debian bug report and was forwarded to us; An early(er) warning could have been useful to avoid this downstream issue.

FYI: we also publish release candidates for every typing_extensions minor release. We'd love as many downstream projects as possible to test against these, so that we're aware of breakages before they happen!

[provinzkraut]

FYI: we also publish release candidates for every typing_extensions minor release. We'd love as many downstream projects as possible to test against these, so that we're aware of breakages before they happen!

Thanks for the pointer, I've added a workflow to test against typing-extension pre-releases on our side as well :)

[python-cla-bot]

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