I am not writing the tests, LLMs are.

My objective is to write prompts for LLMs that can write prompts for LLMs that can write code.

When there is a problem downstream the descendant hierarchy, it is a failure of parent LLM's prompts, so I correct it at the highest level and allow it to trickle down.

This eventually resolves into a stable configuration with domain expertise towards whatever function I require, in whatever language is best suited for the task.

If I have to write tests manually, I have already failed. It doesn't matter how skilled I am at coding or capable I am at testing. It is irrelevant. Everything that can be automated should be automated, because it is a force amplifier.