The proposed PR removes the following unittest features:

* "fail*" and "assert*" aliases of TestCase methods.
* Broken from start TestCase method assertDictContainsSubset().
* Ignored TestLoader.loadTestsFromModule() parameter use_load_tests.
* Old alias _TextTestResult of TextTestResult.

Most features were deprecated in 3.2, "fail*" methods in 3.1, assertNotRegexpMatches in 3.5. They were kept mostly for compatibility with 2.7 (although some of them were new in Python 3 and not compatible with 2.7).

Using deprecated assertEquals instead of assertEqual is a common error which we need to fix regularly, so removing deprecated features will not only make the current code clearer, but save as from future errors.

New changeset b0a6ede3d0bd6fa4ffe413ab4dfc1059201df25b by Serhiy Storchaka in branch 'main':
bpo-45162: Remove many old deprecated unittest features (GH-28268)
https://github.com/python/cpython/commit/b0a6ede3d0bd6fa4ffe413ab4dfc1059201df25b

Per https://mail.python.org/archives/list/python-dev@python.org/thread/GJTREADEXYAETECE5JDTPYWK4WMTKYGR/ we want to revert this change for 3.11 as it causes adoption pain for little benefit.

To determine if we should proceed with this in 3.12 or future versions, run a stable Python with this change applied on the test suites of external projects to find regressions.  (many will have been addressed by then thanks to the work by RedHat)

and remember that those are only open source projects. Peoples internal codebases are full of use of these names and this will prevent upgrading until they take the time to address those.

There are targeted pieces of this change that may make sense to go forward with individually.  But it is easier to reason about after a rollback and consider new PRs to move those forward.

New changeset b50322d20337ca468f2070eedb051a16ee1eba94 by Gregory P. Smith in branch 'main':
bpo-45162: Revert "Remove many old deprecated unittest features" (GH-30935)
https://github.com/python/cpython/commit/b50322d20337ca468f2070eedb051a16ee1eba94