while building 1.1.3 (doesn't happen with 1.1.2) debian package, and showed to @effigies and @mgxd , pytest process never exits with some processes started within test_CommandLine_prefix still running in the background, not killed.
With some manual bisection it seems boiled down to config.enable_resource_monitor() call within test_resource_monitor.py. Even if all tests are skipped in that file, that call is ran while pytest is just collecting the tests, so it is "in effect".
I wonder if that relates to 87ef62f (and may be some related changes)?