Comment by tonymet

7 hours ago

AI is the reality that TDD never before had the opportunity to live up to

Not just TDD. Amazon, for instance, is heading towards something between TDD and lightweight formal methods.

They are embracing property-based specifications and testing à la Haskell's QuickCheck: https://kiro.dev

Then, already in formal methods territory, refinement types (e.g. Dafny, Liquid Haskell) are great and less complex than dependent types (e.g. Lean, Agda).

  • What about model-driven development? Spec to code was the name of the game for UML.

    • Setting aside that model means something different now … MDD never really worked because the tooling never really dealt with intent. You would get so far with your specifications (models) but the semantic rigidity of the tooling mean that at some point your solution would have to part way. LLM is the missing piece that finally makes this approach viable where the intent can be inferred dynamically and this guides the implementation specifics. Arguably the purpose of TDD/BDD was to shore up the gaps in communicating intent, and people came to understand that was its purpose, whereas the key intent in the original XP setting was to capture and preserve “known good” operation and guard against regression (in XP mindset, perhaps fatefully clear intent was assumed)