gh-116789: Add more tests for inspect.getmembers

[sobolevn]

It basically checks that getmembers is equal dir(...) + getattr for these types.
I've covered all types that were mentioned in the docs.

• Issue: inspect.getmembers is not fully tested #116789

[serhiy-storchaka]

All these tests are just copies of each other. They do not contain anything specific to the specific type, so why add them? A test for arbitrary user object should be enough. They only depend on the result of dir(), if it returns an empty list, all tests will automatically pass.

[sobolevn]

Sorry, I lost this PR in the notifications at some point.

I addressed @serhiy-storchaka's feedback:

• I added two classes: one for correct __dir__ and one for __dir__ with extra item that does not exist
• I no longer use dict, checks are made specific
• Extra tests are removed

Thanks a lot for the feedback and notification! 👍

[vstinner]

LGTM.

@serhiy-storchaka: Do you want to review the updated new tests?

[sobolevn]

It was up for 2 weeks, so I am going to merge this, we can add more tests later. Thanks a lot for the reviews, they were very helpful.

[miss-islington-app]

Thanks @sobolevn for the PR 🌮🎉.. I'm working now to backport this PR to: 3.12, 3.13.
🐍🍒⛏🤖

[bedevere-app]

GH-123129 is a backport of this pull request to the 3.13 branch.

[bedevere-app]

GH-123130 is a backport of this pull request to the 3.12 branch.