Auto Insurance Claims: Auto claim, liability insurance policy, auto body shop

Question
A car hit me from behind while I was waiting traffic light to turn green.  He acknowledged it's his fault, since it's a minor accident, we didn't wait police to write a report and just exchanged insurance information.  Now I found out the driver is not the owner of the car, he is an auto mechanic who was testing a client's car.  Insurance company (State Farm) policy says the car is not insured in this case since the driver is an auto mechanic.  Should I ask the driver or the owner to pay the small damange (estimated by an auto body shop at $500)?

Answer
The owner is not responsible.

The driver and/or his employer (the repair shop) is responsible.  The repair shop likely has a "garage liability" insurance policy that will cover their liability.

If they do not have insurance, then your insurance company should cover your damages under your uninsured motorist coverage, but that probably has a deductible that you won't want to pay.

Worst case scenario, the repair shop owner should pay you direct for your damages.  And if they refuse, you can take them to small claims court.  You will not need a lawyer for this.