This feature is to enable pytest.set_trace() calls to use more advanced and less known features of pdb.

Right now, there is an assumption that pdb.Pdb doesn't take any extra arguments. Although it's not really publicized, or even written much about, when debugging asyncio, you get into the pain that the IOLoop doesn't let you follow your application flow easily.

Every await call will be lost in the depths of the eventloop logic, and it's difficult to find your way back to your program.

This feature would allow you to do something like the following:

import pytest; pytest.set_trace(skip=['asyncio.*', '_weakrefset.*', '_collections_abc.*', 'selectors.*', ])

Where all keyword arguments to set_trace would be passed to Pdb class instantiation.