Storybook Testing Workflow Knowledge Modules

A story is the cheapest reviewable proof that a component change does what the ticket says — and since Storybook 9 it can also be a real CI gate. This module covers current-major setup (the v9/v10 package moves that silently break v8-era config), CSF 3 stories, play-function interaction tests, the Vitest addon gate, the a11y ratchet, and what snapshot and visual checks do and do not cover. Establish the repo's Storybook major before writing anything. Everything below documents the current major, and most of it is wrong for a 7.x or 8.x codebase — then open a neighbouring story and copy its idiom, because the house convention beats the docs. storybook majors and release dates, from the npm registry on 2026-08-08: A repo's adoption date bounds the major it started on, not the major it runs today: routine dependency bumps are exactly the kind of work a customer-facing changelog omits. From history alone the honest position is "the major current at adoption, current major unknown" — settle it from package.json, not from when Storybook first appeared. Consequence, and it holds either way: before writing a story, open an existing one and copy its idiom. Everything below documents the current major, and every example is wrong for 7.x. The mismatch is only partly loud — a removed package errors on import, but a removed config key (docs.autodocs, globalTypes.defaultValue) just silently stops working, and a renamed import that still resolves from a legacy package rots without complaint.