Check for continuity across the primary terminals. If you have a VOM check the resistance. Should be 1.6 ohms +/- 0.2. You can aslo check for contiuity of the secondary circuit in the coil by connecting a VOM between the tower terminal and the metal case. Resistance should be zero.
Another way to functionally test is to make sure the points are set properly and remove the center lead from the distributor cap and hold it near a good ground. Turn on the ignition and crank the starter. You should see a FAT, BLUISH-WHITE SPARK, the color of lighning. This tests the entire primary circuit and the secondary.Unfortunately, if you don"t get the requisite spark, it could also be due to a problem with the points or the rest of the primary circuit.