Your best bet is a low mileage used car, particularly a so-called program
Make your selection and take it for a short road test, as the dealer
expects any prospect to do. If you like the car, then proceed:
Since its a used car, the dealer will not object to your taking it for an
extended road test. Offer to pay the gas in all fairness and tell him you
want to drive it a couple of HOURS or even a DAY. You need to put on about
100 miles to really know the car enough to lay down your cash and buy it.
The advantage of a long test run is to really check out the car. You will
learn if it consumes oil, overheats, loses coolant, has any vibrations at
high speed & check its handling, braking, steering, shifting when warm,
behavior on hills, etc., etc.
Think back. You don't know what you have until you've owned it a while.
An extended drive will wring out any problems that you will otherwise
unpleasantly find out if you don't. The dealer should not object, since
what's a hundred miles more on a car that already has maybe 15,000 miles?
If you offer to pay gas and he refuses you, go somewhere else where the
dealer has nothing to fear from potential defects being revealed.