# S016 - Web UI behavior tests

One isolated place: `app0/web/tests/`. Vitest + happy-dom — no real
browser.

## Layout

- `tests/server.ts` - **FakeBff**: the production `linji serve` API
  contract in memory (invite gate, bare-name normalization, sessions,
  member-only space ACL, push endpoints). EventSource listeners are fed
  `update` events when writes land in their space, mirroring the
  server's zds watch.
- `tests/setup.ts` - environment wiring: `fetch` -> FakeBff,
  EventSource mock fed by the fake, Notification / PushManager /
  serviceWorker mocks, `resetEnv()` between tests.
- `tests/app.test.tsx` - 19 tests over the rendered App: login (hint,
  invite field visibility, wrong invite, wrong password, bare name),
  spaces (empty state, invalid URI, join, non-member denial, thread
  expansion), posting (disabled button, post + composer clear, new
  thread), SSE live update, open-app notifications (hidden tab fires,
  own posts and visible tab don't), the bell (permission + push
  subscription registration), logout.

## Run

`cd app0/web && bun run test` (NOT `bun test` - that is Bun's own runner, which can't transform the Solid JSX). ~1.5s.

## Gotchas found (test-side)

- Vitest resolves solid-js's `node` export condition (server build,
  renders nothing). `vitest.config.ts` aliases `solid-js` and
  `solid-js/web` to their browser `dev.js` builds.
- `<For>` keys by reference: a refresh replaces the whole thread
  section (new JSON objects), so assertions must re-query elements
  after a refresh.
- Seed/mutation state in the fake must be reset between tests
  (`resetEnv` restores `inviteCode` too — one leaked mutation hid the
  invite field for every later test).