discovering-vendor-behavior

Find out what the dependency does before you design around it.

A Veris sandbox is a stateful twin of the service this code calls. It answers questions no amount of reading the codebase can — what the vendor returns on a repeat, what it does when a response is lost, which of two designs it makes unnecessary — and it can make those situations happen, which the real vendor will not do on demand. Those answers are cheap here and expensive in production.

Core principle: a dependency's contract is measurable, so measure it

The design you choose is a claim about the dependency. If the claim is wrong, every test you write still passes: you will be testing your workaround, not the behaviour it was meant to protect.

Where this sits