Problem is, it’s an engine - they have no idea what the vast majority of people are doing with it. 9 times out of 10 a lot of issues people run into with the engine are actually entirely down to the project. I’m sure Epic are clued up on Unit Testing and CI - any software developer worth their salt is, but perhaps right now it’s not feasible (or for all we know, maybe they are already doing it?)
The biggest barrier I can see tbh is that setting up unit tests takes a massive amount of time and money, and usually it’s a full time job for several people. With such large parts of the engine being under constant re-design, maintaining those tests and keeping them up to date probably costs a huge amount in maintenance too. If Epic were to say, hire a bunch of people who know the engine well enough to design these unit tests, it probably makes more sense to have those guys developing new software rather than verifying old software.
With such a massive community and Epic using the engine themselves, I don’t think it’s a huge necessity because we serve as the test bed. While I get that that’s not ideal for those of us who want to update to the latest features asap and have everything working without issue, I just don’t think that’s a possible reality - unless you have the budget for a huge team.
Who knows though. Maybe an Epic engineer will chime in here…