@simonw's successful port of JustHTML from python to javascript proved that an agent iteration + an exhaustive test suite is a powerful combo [0].

I don't know if TLA+ is going to suddenly appear as 'the next language I want to learn' in Stackoverflow's 2026 Developer Survey, but I bet we're going to see a rise in testing frameworks/languages. Anything to make it easier for an agent to spit out tokens or write smaller tests for itself.

Not a perfect piece of evidence, but I'm really interested to see how successful Reflex[1] is in this upcoming space.

[0] https://simonwillison.net/2025/Dec/15/porting-justhtml/ [1] https://github.com/reflex-dev/reflex