First, if you are hooking the battery up to the wires that go to the pump....make sure the wires have continuity all the way to the pump.
Second, the fuel pump could just be "froze up". Old gas will turn to varnish and make the insides of the pump stick together and it won't run/turn. If it is froze and you haven't had it hooked up too long and burnt it up inside, then you may be able to get it working again. Here is what I have done to bring some dead pumps back to life......
Do the following at your own risk
Get some Simple Green (cleaning solution).
Put a mix (I use it 100%, but some people dilute it 50/50 with water) of Simple Green in a tin can big enough to submerge the pump.
Do the following outside......
Place the tin can on a hotplate (a camping stove or a gas grill will work too).
Place the pump in the solution.
Start heating the solution up.
While it is heating up, occasionally hook up the pump wires to see if the pump is freed up (be careful doing this...the pump will squirt the solution a long ways and the solution will be very hot and will burn you!!!!!). I hook up a hose to the outlet of the pump and stick the other end of the hose back into the solution (but be sure to hang onto the end of the hose, the pump will pump the solution hard enough that it will blow the hose out of the can). If it doesn't run, unhook the wires quickly (don't leave them hooked up for more than about 3 seconds at a time).
Occasionally keep checking for pump operation.
I have had some pumps that have freed up within minutes of being in the solution, and some that have taken an hour or more to free up, and some that never run.
If you get the pump freed up, contine to run it for a few minutes, to circulate the solution through the pump and clean out the buildup on the inside.
Once the pump is cleaned out and running good, remove it from the solution, and put it in a can of clean water, and hook the pump up again to flush out the Simple Green solution.
Remove the pump from the water and shake out as much of the water from the pump as you can.
If you are going to store the pump and/or not use it immediately....squirt some wd40 or similar into the bottom of the pump, to lube it up and to keep it from sticking again while in storage.
Third, it also could be that you have a dead spot in the pump. I had a pump that would start/run 90% of the time. But every once in awhile, the pump would not start and run until I tapped on it. Then it would run fine. If you get a dead pump to work again, start and stop it several times, to make sure you don't have a dead spot in the pump. If you do have a pump that won't start occasionally.....throw it away.
Or some of the internal wiring in the pump could be damaged/broken/shorted. If this is the case, the pump will never run again, so it is junk.