But recording and replaying matches? Taking screenshots and comparing the output? Just think about it: If you have recorded a match and change the hitpoints of a single creature, the test could possibly fail. And then? Re-record the match?
The same applies to screenshots: What happens if models, sprites or colors change?
In my experience, tests like this are annoying, because:
1) They take a long time to create and adjust/recreate.
2) They fail for minor reasons.
3) It takes time to understand, what such tests even measure, if someone else made them.
4) You need a large, self made framework to support such tests.
5) It takes a long time to run them, because they are time dependent.
6) They hinder you to make large changes.
7) It's cheaper to make some low wage game testers play your game. Or better, make the game early access and let 1000s of players test your game for free, while even making money out of them