Run binary from test suite

(Resending due to moderation.)

Hello!

I'm a Google Summer of Code student, writing some tests for the FreeBSD 
test suite, and putting them under src/tests.  I need to run some 
binaries, specifically pfctl.

How should I call pfctl from my test scripts?  Should I call it directly 
and let the shell find the binary in the path?  Or should I find where 
the build version got created (somewhere under /usr/obj) and call that? 
How do I find where the binary ended up getting created in that case?

Best regards,
Panagiotes