Running tests for a single program in src/bin, src/usr.bin, etc

Hi everyone,

Not sure if this is the best list for this. Maybe hackers@ would be better?

I wanted to tinker with utilities in /usr/src/bin and /usrsrc/usr.bin. I noticed that rmdir exits 1 for usage, which is a pet peeve of mine. I updated it to exit 2 and then wanted to alter the tests to ensure it's exiting 2.

At this point, I'm unsure of how to run tests for this single component. Is there a way I can be in /usr/src/bin/rmdir and just run a succesful `make test` (or equivalent) without some combination of `make install` + kyua out of /usr/tests? Seems like for self-contained tests, simple testing should be possible.

I did find `make check`, but I'm having issues with checkdir sticking around.

Thank you!

-Henrich