Test for ohms resistance of the primary winding between + and - terminals, and test ohms resistance of the secondary winding between either terminal and the coil output terminal. Typical values might be 1 or 2 ohms and 8k for primary and secondary. Ignition coils do fail though not very often.

I must be Dunce of the Day!  Is there a simple, on car, test for the coil without special tools?

What I have:  1954 Merc, stock 256, 6 volt, positive ground.
Problem:  No power to the distributor (points).  There is power to the ignition terminal on the coil with the ignition switch on.  The coil to distributor wire is intact and properly connected and just to be sure, I used a by-pass jumper wire to verify.