Test Track is a side mission in Grand Theft Auto: Vice City which is triggered when entering the parked Landstalker on the dirt track in Downtown. It is a checkpoint mission, but it has no time limit. It is essentially the reverse of Trial By Dirt, which is started by jumping on the Sanchez instead. To complete this mission, you must clear each checkpoint without exiting or destroying the car. It is much easier than the previous Landstalker mission in Grand Theft Auto III, entitled A Ride in the Park.
You can keep playing this mission once you've completed it. Each time you beat your time record, you receive a higher prize (in money).
Due to a bug in the game, the initial scores of both Trial By Dirt and Test Track will have the same time results once both scores are listed in the game's stats. Once you play the missions again and beat each time, the scores will be individual as they should be. The bug can be avoided by completing Test Track before Trial By Dirt.