[toddh]

Contracts are basically unit tests for whatever size of unit you're testing. How do you capture all the dynamic behaviors of a system without some sort of end-to-end test? Delayed timers, queues fill, missed interrupts, locks are held for too long, dead lock, live lock, priority inversion, dropped messages, out of order issues, etc. These things are not captured by contracts and are often exactly why the end-to-end tests were flakey in the first place.

[JackFr]

System A listens to queue B and handles every kind of message b throws at it. But somewhere, at some point in time, some coder has made the innocuous assumption that B_id's are unique.....