[Vanishing Point]

Hook up a fuel pump pressure gauge to the Schraeder (spelling?) valve on your fuel rail. Be sure it is a gauge that is designed for Fuel Injection systems (able to handle at leat 60 - 70 psi or you'll have gas squirting everywhere).
Should be between 50 - 60 pounds.

If not then check the fuse to the fuel pump.

My 1997 GTS manual says:

1. release fuel system pressure.
2. disconnect negative battery cable at the auxiliary terminal.
3. access fuel pump module cover by pulling back trunk rug.
4. drill pop rivets from fuel pump module cover using 1/4 inch drill.
6. use special tool 6856 to remove fuel pump module locknut.
7. lift module up to remove, being careful not to spill the fuel remaining in it.

I guess you could check the voltage at the pump at that point (you'd have to hook up the battery again; be sure no fumes are present either at the battery terminal or at the poin that you are checking the voltage to the pump..

Did you change the fuel filter? If clogged then you'll get lower or no pressure.

 

[Vanishing Point]

Once the pump is out you could hook it up to 12 volts and see if it spins.

Caveat #1. Once when my Hummer had a bum fuel pump I tried this and it spun fine BUT when I dipped the intake and pump into mineral spirits it was not pumping anything.

Caveat #2. If you want to test it for ability to pump I would NOT test it with gasoline as it will spray a 60 psi stream of gasoline all over the place. Use a less flammable non water based liquid to test it that way (mineral spirits work fine). better yet hook it up to your pressure gauge. Immerse it in the fluid you are testing it with so that it will be properly primed.

Caveat #3. Do not run the pump without liquid for more than a second or two. Also once out of liquid the pump will tend to overheat so run it for no more than a few seconds if it is in the air even if it is pumping liquid. In tank fuel pumps are cooled by being immersed in fuel and running them in air can cause them to overheat.

 

[Vanishing Point]

Be very careful. The combination of gasoline fumes and electrical sparks might cause you to die in a fire.