The NetBSD test tests their version of CPUSET(9); not sure if they're providing much value beyond testing the shims that I threw in, but the parts that are testing with valid cpu indexes seem useful.
The cpuset(2) tests should be run as root (require.user properly set) with >= 3 cpus for maximum coverage. All tests that want to modify the cpuset don't assume any particular cpu layout (i.e. the first cpu may not be 0, the last may not be first + count) and the following scenarios are tested:
1.) newset: basic execute cpuset() to grab a new cpuset, make sure the assigned cpuset then has a different ID.
2.) transient: create a new cpuset then assign the process its original cpuset, ensuring that the one we created is now gone.
3.) deadlk: test assigning an anonymous mask, then resetting the process base affinity with 1-cpu overlap w.r.t. the anonymous mask and with 0-cpu overlap w.r.t. the anonymous mask.
4.) jail_attach_newbase: process attaches to a jail with its own cpuset+mask (e.g. cpuset -c -l 1,2 jail -c path=/ command=/bin/sh)
5.) jail_attach_newbase_plain: process attaches to a jail with its own cpuset (e.g. cpuset -c jail -c path=/ command=/bin/sh)
6.) jail_attach_prevbase: process attaches to a jail with the containing jail's root cpuset (e.g. jail -c path=/ command=/bin/sh)
7.) jail_attach_plain: process attaches to a jail with the containing jail's root cpuset+mask.
8.) badparent: creates a new cpuset and modifies the anonymous thread mask, then setid's back to the original and checks that cpuset_getid() returns the expected set.