[CamperBob2]

Why don’t you have automated test coverage so you’re free to make maintenance or engineering improvements without fear of breaking things?

Because that's equivalent to solving the Halting Problem. Even if you could test your way to quality in a non-interactive context, it would never be possible in a system that includes asynchronous human input.

[heavenlyblue]

Just don't make asynchronous human input turing complete, there's plenty of machines for which the halting problem is solvable.