To run the fuel pump for testing purposes you will need to supply power to it without starting the engine. On most cars this can be done by unplugging the fuel pump relay and placing a jumper wire from pin #87 to pin #30. This should cause the fuel pump to run at all times. If you do a lot of work on cars with the same relay type, you may want to take a old fuel pump relay, cut out the circuit board and solder pins 30 and 87 together, this way when you need to do testing on the fuel system you just plug in your test relay. I have also seen these test relays with a toggle switch mounted on them.