I can tell you not to waste your time checking that. You can completely remove the fuel pump relay with the engine running and it won't stall. It has a redundent power feed through the oil pressure switch and doesn't even need a relay to run. it would just have a long crank before starting..
The oil pressure switch would have to be shot and not working for the relay to effect the running.
You can really test the reliabilty of the relay. You would have to just replace it to find out.