test_offcial has evolved greatly over time with #3868 introducing yet more extensive testing.
To keep order in there, we should try to get it a bit more moduler. Ideas:

• move helper functions to a different module
• move configurations about PTB exceptions to a different module
• make checking of existence, optional arguments, type hints different module
• Maybe class-based approaches (e.g. wrapping python objects and corresponding documentation into one container) may make sense