I've made testdir.runpytest_subprocess work with pdb.set_trace(), but it currently requires to set stdin=None (instead of a new default (CLOSE_STDIN)), and use -s.

I think the latter could be solved by using MultiCapture also for runpytest_subprocess, and use MultiCapture(Capture=FDCapture) also for runpytest_inprocess (it uses SysCapture currently).

Then those would also need to be handled/managed by the the capmanager plugin, and this would likely allow pytest's set_trace to suspend capturing then also.

Thoughts?