I also wanted to know if TehAgent's old leaky pump still worked after I had pulled it to bits and reassembled it. It was the first time I'd had a Bosch pump in bits.
I set up a very crude test rig consisting of a fuel header tank (a funnel actually) and a fuel return catch tank (a small glass jar). I did not have any pukka diesel test oil and did not, for obvious safety reasons, want to use real diesel so I chose to use vegetable oil.
I set the pump up with its test fuel lines and a battery nearby to energise the stop solenoid.
I filled the funnel and gently squeezed the pipe to persuade the pump to fill with oil. An old priming bulb would be useful here but eventually the pump will fill. Then swing the pump over in a clockwise direction using a ratchet. Swing it until oil appears in the return line. Engergise the stop solenoid and swing again. Observe nice jets squirting from the injector outlets and oil running down the return line into the catch jar
Both pumps work fine but TehAgent's still leaks
The other pump leaked nowhere on the test so I'm relatively confident that the admittedly crude test is good enough to find bad leaks and prove basic functionality. Obviously it will not test the advance servo but at least I'm reasonably confident that I can fit the pump and it'll stand a chance of it working. Also, any muck in it will have been flushed through.
That is my test rig. Please don't laugh at it

Perhaps a useful test for a pump of unknown provenance that has been rescued from a scrapyard.