this is what we're doing in Libre-SOC, and using standard python software engineering practices (writing unit tests at every step of the way) to do it. some of those unit tests are actually Formal Correctness Proofs (asserts, but for hardware).

i was stunned to find that in the hardware world, test-driven development is not standard practice: people simply haven't been trained that way. they write thousands to tens of thousands of lines of unverified code and finally do an integration test.