[phamilton]

> perfect refactor-proof testing contracts are still usually pretty hard to design

Not sure about hard, but definitely rare and we as an industry are under-skilled in these areas.

We have decades of research and tools for testing and verification of software. Property tests, dependent types, formal verification and proof, etc. The paths have been there, we have just collectively prioritized other things.

It requires an intentional shift in how we design and build. That shift is the harder part.