Testing is so hard that we'll agree that, e.g., TDD is great (e.g. ensure your tests actually test something, ensure your code is testable from the start) yet we never do it. And when we do write tests, we are on the hook to be eternally vigilant that they are not stale, that they test something real, that they are not redundant. And they often turn into an append-only file that you resent.

Meanwhile, AI is happy to write tests, do red-green TDD cycles, refactor them, prune them, update them, justify and defend them. It will even incidentally write tests for the most aloof vibe-coder by accident because they didn't specify otherwise.

Overnight, I went from never testing most of my side projects (except for, say, maybe unit tests in more straightforward things like a parser) to now everything is tested end-to-end. Every time I make a new directional / architectural decision, the tests the AI writes also encode it at the test level to reenforce the decision.

It's strictly a better world for software because AI can write and maintain tests.

> LLM-assisted codebases, at least these days, only stick together thanks to testing

But tests also help humans and ensure human-written software is robust. We only don't test because they are so costly to write and maintain, and our software has always suffered for it. Or the tests become such an unmaintainable mess that our software is now worse because of it!