Here we distinguish between damage suffered by third parties as a result of an accident and damage to the vehicle itself.
Damage to third parties: The vehicle owner's motor third party liability insurance covers property damage and bodily injury suffered by third parties in the event of an accident with the car.
Damage to the vehicle: Damage to the test vehicle itself is covered by the (comprehensive) insurance, if such an insurance exists. Otherwise, the driver must always pay for the damage himself/herself. If the driver has third-party driver's insurance, this will cover the damage. Third-party driver’s insurance can be part of a household insurance policy.