This was some info that was given to me by a friend of mine for testing coils. It came out of the old Maytag engine booklet. Coil testing: Test coil and condenser with a Hot Shot battery as follows: Connect positive terminal of the battery to the stationary breaker point. Place a strip of paper between the points and move wire from other terminal of battery back and forth over the breaker blade and at the same time hold the spark cable 1/4" from the plate. If a spark jumps from the cable, the coil and condenser are evidently all right. If no sparks appears, disconnect condenser and again test as described. If a spark now appears, the fault is in the condenser and a new one should be installed. However, if there is still no spark, disconnect coil, connect condenser and test again. This procedure is a definite method of testing for a dead coil or condenser.
Warning: to large of battery could damage coil, I recommend 1 1/2 volt D Cell
Hope this helps