I would think the best bet would be to try testing it while it's still on the truck. You can monitor the pressure at the schrader valve. The flow could be monitored by disconnecting the supply and return hoses and running a new set of hoses to a bucket/jar/bottle of clean diesel.
Well I agree with you, BUT, when I changed mine, the culprit of the leak wasnt (apparently) the fuel pump, was the fuel lines and the bottom of the canister, but anyway I changed the pump, and I have the OLD pump in my bench, and I would like to know if it works well or not, so that the reason Im in this post. And Im not going to do the work again, just to test the pump in my truck, do you know what I mean? Its not an easy job as every body knows. I think that is not possible though.