Jason, do you mean test to see if they work, or test to see if they drag?

If you want to check for excessive drag, you wrap a bungee cord around the wheel lugs and attach it to one of those tension gauges (I think they usually read in ft*lbs) and there is a specification for how much drag the setup should have. If it's over that specification then you need to have somethng fixed.

If you want to check if they work, I'd say a big parking lot, taking it easy, gradualy increasing speed with each try of the brakes, and have a hand on the e-brake just in case :) Or you could spin the wheel while the car is in the air and test it that way, to at least make sure it's doing something. I know, not two very good suggestions, but it's the best I can do.