Testing a running system is very simple. With the points closed, engine stopped, and the ignition switch in the "run" position, there should be around 9 to 9.5 volts at the coil (+) terminal if the system is working "as designed". On the distributor side of the coil with the "points closed- - - -switch on" a voltmeter should show virtually no voltage- - -less than 1/2 volt, maximum. The less the better on the distributor side. Higher voltage indicates dirty or burned points. During cranking, the coil should be getting very close to full battery voltage if the resistor bypass system is working correctly. Have fun!
Jerry