But conformance testing is where agents really excel at if you set things up right:

* Black-box testing: the agent writing the tests cannot see implementation and the agent writing implementation cannot see tests, they only agree on a spec and an interface (the minimum needed to write tests).

* Evaluate test coverage using code coverage, but when gaps are found communicate those gaps in terms of the specification.

Good specs should be grounded (complete and not ambiguous), they don't need to be formal. You should be able to re-run your agents when the spec changes on diffs to the spec, and if a change happens out of bad, you should have agents that go in and propose fixes to the spec. Since agents are doing deterministic codegen like a compiler would, this is all pretty straightforward.

You also need to consider public and internal specifications (the public specification being for reuse of the component), and you might test your integrating component with a test-double (built from the public specification alone) rather than the real component itself.