I guess you could check a pump by hooking it to a partially closed valve and pressure gauge and feeding it with good elec. power.
Adjust the pressure by turning the valve and measure the GPM by filling a bucket while timing it.
If the pressure and GPM match what the pump's curve says, at both end points and one place in the middle of the curve, I don't see how it can't be a good pump/motor.
With all the trouble of getting to the pump and the cost of these things, I'd even check new ones before installing them.