Now if ChatGPT would be able to actually work on the problem rather than returning generated text, that would be a completely different beast. And I think that this workflow will come in the near future because it's pretty obvious idea. Get task specification, generate tests, generate code, fix code until tests work, refactor code until it meets some standards, etc.
You give junior devs way too much credit. They rarely test corner cases.
ChatGPT probably works great if you use it to speedrun normal best practices in software engineering. Make it start by writing tests given a spec, then make it write code that will pass the specific tests it just wrote. I’m guessing it’ll avoid a lot of mistakes, much like any engineer, if you force it to do TDD.