That is called "Volkswagen" testing. Some years ago that automaker had mechanism in cars which detected when the vehicle was being examined and changed something so it would pass the emission tests. There are repositories on github that make fun of it.
While that’s the most famous example, this sort of cheating is much older than that. In the good old days before 3d acceleration, graphics card vendors competed mostly on 2d acceleration. This mostly involved routines to accelerate drawing Windows windows and things, and benchmarks tended to do things like move windows round really fast.
It was somewhat common for card drivers to detect that a benchmark was running, and just fake the whole thing; what was being drawn on the screen was wrong, but since the benchmarks tended to be a blurry mess anyway the user would have a hard time realising this.
