Man, I wish we would have even thought of testing ours before putting it in. It was working fine when we pulled ours our (4 years earlier). When we put it back it was leaking like a seive! We figured the seals were dry, so we used the stuff you pour in with the steering fluid that is supposed to lubricate the internal seals. Didn't do anything. We ended up replacing the entire steerring gearbox AFTER we had installed the entire engine, headers, starter, etc. Pain in the butt!!
If there is a test...do it now.