[issue40129] Add test classes for custom __index__, __int__, __float__ and __complex__

[Serhiy Storchaka]

Change by Serhiy Storchaka <storchaka+cpython at gmail.com>:


----------
keywords: +patch
pull_requests: +18618
stage:  -> patch review
pull_request: https://github.com/python/cpython/pull/19262

_______________________________________
Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue40129>
_______________________________________