Testing

Vitest runs two projects. unit runs *.test.ts(x) with jsdom and Testing Library; src/testSetup.ts stubs ResizeObserver, matchMedia and scrollIntoView, which jsdom lacks. storybook renders every story in headless Chromium and runs its play function.

Command	Does
npm test	Run the unit tests once
npm run test:stories	Run every story as a test in headless Chromium
npm run lint	oxlint
npx tsc -b --noEmit	Typecheck
npm run build	Typecheck and production build

CI runs install, lint, typecheck, unit tests, story tests, the app build and the Storybook build on every PR, and publishes the image on master.

Before the first npm run test:stories, install the browser once with npx playwright install chromium.

tip

If Vitest workers crash, use Node 22 rather than an older default.

How do I write a test?

• Put it next to the file, as Thing.test.tsx.
• Mock fetch or the functions in src/api/; tests never reach a real API.
• Render pages inside a QueryClientProvider and a MantineProvider. Seed the config through localStorage under fantasy-web-ui.draft-config.
• Use fixtures with synthetic players and IDs only. See Docs style guide on personal data.