For a test you dont need one. You could use the one you have by disconnecting the electronic ignition feed with a 12 volt positive feed.

But I would just feed a direct 12 volt positive to the coil for max performance for the test.

The stock ignition setup sends full voltage to the coil on the start up position and then sends reduced voltage to the coil on run position through the ballast for Extended point life. Since your just doing a short test, no ballast resister is needed.

Your simple test can be as easy as removing the electronic coil feed and replacing it with a hot positive feed jumper with the "test" points distributer. No need to rewire everything

Simply put, with a point distributer all you need is 12 volts pos to the pos side of the coil and run the neg. side of the coil to the distributer that will ground it out when the points contact.