I tested my pumps through just taking them off and connecting to the terminals on the pump itself. You can choose any method you would like. I had an issue with this once, and it was just the pump. A huge word of advice on this as well (if it is the pump you need), if you are going to pick a part it, take your broken pump with you. I found out really quickly that there are many different types of them, some have an elbow, some are straight, different size input/output holes etc. I would also take the rubber elbows, fittings etc that go to the line, trust me - just do it.
I had to go down three times when I replaced the reservoir, thinking there were just a change to the design when the facelift for the gen occurred, but boy was I wrong. I've seen more than four different styles of bottles/pumps. If you decide to go that route anyway.
Good luck.
-Kevin