How can you test a RYOBI battery charger to tell if it is good?

I have a 14.4 volt ryobi cordless drill. I tried charging the battery but the charge light wont come on now on the charger it never did this before. could it be the battery is so dead it wont let it charge? or might it be the battery charger? I hate to buy a new batter if the charger is no good because if I must buy a charger also I can come out cheaper buying a new drill. can u test the battery charger with an multi tester? i see where you put the batter in to charge it has 3 metal contacts. what reading should you get if you use the multi tester?