· 6 min read
What We Learned Running 10,000 Property-Based Tests Against a Calendar Engine
Property-based testing caught DST double-counting, leap year edge cases, and RRULE bugs that unit tests missed. Here's our proptest setup.
Property-based testing caught DST double-counting, leap year edge cases, and RRULE bugs that unit tests missed. Here's our proptest setup.
A 9am weekly standup crosses spring-forward. Here's what goes wrong with naive implementations and how deterministic tools get it right.
We ran 5 real-world RRULEs through frontier LLMs and the Truth Engine. The results show why calendar math needs computation, not prediction.
Why we built a Rust-based RRULE expansion library with 9,000+ property-based tests — and why AI agents need it.