Writing tests against a bad implementation usually doesn't work well. In this scenario I would have an LLM look at the changes in the branch and try to create a markdown document of the changes, why it thinks they were made, etc. and then review that doc with the manager and do a new implementation from scratch after aligning.

Unless the tests are written against logic that is in of itself subtly wrong and even the structure of code and what methods there are is wrong - so even your unit tests would have to be rewritten because the units are structured badly.

It’s a valid direction to look in, it just doesn’t address the root issue of throwing slop across the wall and also having unrealistic expectations due to not knowing any better.

Be careful with this because the LLM will just change the tests on you to get them to pass.