Game designer checking in. Unit tests are very rarely used in games. This is partially because they are so interactive, and partially because it would take a lot of time away from something else. The video game industry has always been under severe crunch. Why would you waste time writing something to check for a bug rather than fixing a different bug or adding a cool new feature? It’s not the healthiest approach but it was inevitable now that we can patch games at any moment.

Here is an example of a game called Factorio running its own unit tests. It’s a lot easier for this game as its deterministic and doesn’t need player interaction to function. https://youtu.be/LXnyTZBmfXM

There have also been attempts to use machine learning agents that act as human players. It’s going to be a while but the idea is that it would automate playtests which are used to hunt down the same bugs. https://youtu.be/ZZsSx6kAi6Y