Essentially, you need to stringent the code review and testing processes. You cannot have AI doing code generation and code review and/or testing together. Either you have code generated by AI, and have Humans review and test the code, or have humans write the code and AI supporting with code review and/or testing the code. Never both.
I find the second approach better - AI supporting with testing and code review processes. Code generation is still Developer's domain and I don't see AI writing Production level code anytime soon. Developers can use AI to generate snippets of code which is then adjusted to make it production ready. That is probably best of both worlds at the moment.
[1]: https://rdel.substack.com/p/rdel-57-what-are-the-most-common