There is a way to test them with a VOM ,but I just unplug the coil wire leading to the center of the distribtor cap and hold the end of the coil wire about an inch or so away from a good ground with a pair of insulated pliers and have someone crank the engine over with the key on, a good coil will put out a strong arc to ground a weak coil will show a yellow weak spark.............
William Rogers.........