Can't belive they told you that there is no way of testing it.

You need to measure the resistance between the coil terminals.

One terminal is 8mm and the other 10mm.

First measure the resistance between the two. It should be between 0.3-0.6 ohms

Then measure resistance between the 8mm and the center tower where the distributor wire plugs in. The resistance should be 8-13 kohms or 8000-13000ohms

If any of these values are different you'll need to get a new coil.

If the coil is good check your crank position pickup.

It connects to your EZL. EZL is mounted right next to the ABS pump on the fender. It has three plugs, the smallest one is the crank position pickup (one pole). First check if it is loose. Clean and bend the female part of the plug so it p lugs in properly. You can also check the resistance on it.
Take the female part (the wire) and test the resistance between the middle and the outside part. It should be 680-1200 ohms. If not replace.

There is a few more things you can check but check those first.

Good luck,
Vin