There's a catch with 100% coverage. If the agent writes both the code and the tests, we risk falling into a tautology trap. The agent can write flawed logic and a test that verifies that flawed logic (which will pass). 100% coverage only makes sense if tests are written before the code or rigorously verified by a human. Otherwise, we're just creating an illusion of reliability by covering hallucinations with tests. A…
IMO it’s quite boilerplate-y to set this up pre-LLM but probably the ROI is favorable now.
Furthermore, as Uncle Bob has written a lot about, putting effort into structuring your tests well is another area that’s usually under-invested. LLMs often write very repetitive tests, but are happy to DRY out, write factories, etc if you ask them.