Several years ago I started to write tests for Unicode C API. It required a lot of effort, because this category is big, so after doing 2/3 of the work I put it off for later. Certain circumstances prevented me from completing it. But now I found time to return to it.

In the meantime, other people have done some of this work (moving parts of the_testcapi.c to a separate files, adding coverage for more C API functions), and some of the legacy C API has been removed. Therefore, it took more than a week to arrange the code, fix conflicts, remove outdated tests and write remaining tests. But some errors may still remain, be careful.

Linked PRs

• gh-99593: Add tests for Unicode C API #99594
• gh-99593: Add tests for Unicode C API (part 1) #99651
• gh-99593: Add tests for Unicode C API (part 2) #99868
• gh-99593: Add tests for Unicode C API (part 3) #104728
• [3.12] gh-99593: Add tests for Unicode C API (part 3) (GH-104728) #106595