how long is a test drive?

Usually Zero. You can't drive off a car until you either pay in full or sign the loan papers.

Once you put a down payment on a vehicle, it's yours until you sign the documents. It's sometimes difficult to get your money back if you do change your mind before you sign for the vehicle, so make sure you really want it.

Many States have a cooling off period for major purchases like a house or vehicle. In New Jersey it's 3 days. Check with your local Office of Consumer Affairs for the laws in your State. Hope that helps! Jim