I have a 94 LS and it wouldn't start so I tested the spark plug against the valve cover and it produces no spark. I used the same plug and method on my civic and it sparked like crazy. So I bought a new cap and rotor but still no spark.

My question is, what could it be and how do I test it?

 

I'll bet the cost of your new ignition coil that the problem is a blown ignition coil. Do yourself a favor, buy a Honda coil, not some cheapo autozone coil. I made that mistake, and it cost me that part, plus the Honda part I had to buy when the cheap one blew a month later. Bolt in that new ignition coil, car should start up right away

 

Could be the coil or the igniter. Do you have an Ohm Meter?