Just spinning the pump by hand it will probably pump even if the shaft sheared as there is no load on it. Checking the gears in the timing cover is easy take a small bar or screw driver and try to rotate them, they shouldn't move unless the engine turns over.
First thing i would do is pull the relief valve out and make sure its clean and nothing is stuck in it.
Second thing is pull off pressure hose and bump the key to see if it pumps anything
Third if no pumping, pull pump apart and check for internal failure.
If it's pumping then I would check to make sure the steering cylinder didn't come apart internally.
If pump is pumping and cylinder is good then orbital valve is the last and most expensive piece.
The steering wheel will turn around and around as the "stops" you feel normally are the cylinder bottoming out.
