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feat(harness): agent-drivable dev harness and CI that gates
A coding agent could develop this repo's Go packages and could not
develop the application: every path to running YellowJacket ended in a
blocking GTK window, so 265 bound methods, 46 events, 33 component
directories and 13 stores had exactly one form of verification
available — `tsc --noEmit`.

The unlock is that `wails dev`'s dev server on :34115 serves the real
frontend with the real generated bindings against the same Go backend a
desktop window attaches to, so a plain Chromium under Xvfb gets a fully
functional app. Four test tiers now exist, cheapest first:

- `make ui-test` — 313 Vitest tests in a real browser in ~2 s, no app,
  no backend, no display. Works because `frontend/wailsjs/` is a pure
  passthrough to `window.go`/`window.runtime`, so faking just those two
  globals runs the real bindings and the real store code.
- `make test` — services in-process, asserting on the payload the
  frontend would receive, via a new `events.Emit` wrapper.
- `make dev-headless` + `playwright-cli` — the real app, driven
  interactively, with an event bridge on `window.__yjEvents` and a
  dev-only control surface at `/__test/`.
- `make e2e` — 19 of those flows frozen as Playwright specs.

`events.Emit(ctx, …)` replaces all 35 direct `runtime.EventsEmit` call
sites: wails' `getEvents` `log.Fatalf`s on any context without its
runtime, so those paths could not run under test and a background
worker could take the app down. Four packages had each hand-rolled the
same guard; nine more guarded on `ctx != nil`, which does not help.
`TestNoDirectRuntimeEmits` fails the build on a new one.

Fixtures are generated, not committed (`make testdata`), and seeds are
built by *running the app* — never by hand-writing config and DB rows,
which would be a second description of a valid YJ_HOME.

`.gitea/workflows/ci.yml` is the first workflow here that tests
anything; the other three only package, so `gitea_ci` reported only
packaging jobs and misled anyone asking whether a push was healthy.
Both jobs were prototyped to green in a bare ubuntu:24.04 container
before the YAML was written, which immediately caught `make lint`
linting three configurations that nothing builds: all three passes
omitted `webkit2_41`, so wails resolved webkit2gtk-4.0 — which Arch
still ships and Ubuntu 24.04 dropped.

Operational instructions live in `.pi/skills/yellowjacket-dev/`,
measured discoveries in `.planning/NOTES.md`, and architecture in
`CLAUDE.md` — split by tense, not by topic, because a topical split
gives every new fact two plausible homes. `make skill-check` fails a
commit if the skill cites a make target that does not exist.
2026-08-10 23:20:42 -04:00

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Markdown

# The harness: event bridge and control surface
Two things ride on top of the headless app. Both exist only in dev
builds; neither is reachable from a shipped binary.
## The event bridge (`.playwright/init-events.js`)
Loaded as an `initScript` by `.playwright/cli.config.json` and by
`e2e/support/fixtures.ts`, so an exploratory session and a committed
spec see an identical page. It records every backend event by wrapping
`window.wails.EventsNotify` — the single choke point all 46 events pass
through, whether or not the app subscribes to them.
```js
window.__yjEvents.wait('LibraryScanComplete', { timeoutMs: 60000 })
window.__yjEvents.names() // name -> count; use this to find out
// what actually fired before asserting
window.__yjEvents.last('QueueChanged')
window.__yjEvents.since(seq)
window.__yjEvents.reset() // drop the buffer
window.__yjEvents.ready(20000) // resolves when a binding round-trips,
// which is later than DOM-ready and true
window.__yjEvents.call('queue.Queue.GetState', [], 5000)
```
- **`wait` resolves against already-buffered events as well as future
ones**, so there is no race between doing the thing and listening.
- **Install exactly one recorder.** Listeners survive across `eval`
calls; a second recorder double-counts. Call `reset()`, never
re-register.
- **`call` times out on purpose.** A binding with wrong argument types
never fires its callback. A 5 s rejection naming `.dev/app.log` beats
an infinite hang.
In specs, use the wrappers rather than `page.evaluate`:
`waitForEvent`, `resetEvents`, `eventNames`, `callBinding`, and the
`app` fixture (a page with the bridge installed and the backend
actually answering) from `e2e/support/fixtures.ts`.
## The control surface (`backend/testctl`, mounted at `/__test/`)
Gated twice: behind the `dev` build tag (with a no-op `!dev` twin) and
behind `YJ_TESTCTL=1`, which `scripts/dev-headless.sh` sets and
`make dev` does not.
| Endpoint | Use |
|---|---|
| `GET /__test/health` | is this a seeded dev build, and which library |
| `POST /__test/db/snapshot?name=X` | save the SQLite state |
| `POST /__test/db/restore?name=X` | put it back (see below) |
| `POST /__test/emit` `{name, data}` | force any backend event |
| `POST /__test/sql` `{sql, args}` | read rows, or a write count |
`TestCtl` in `e2e/support/fixtures.ts` is the typed client.
- **`emit` is the fast way to render a push-driven view** without
staging the work that would produce it — job progress, download
progress, scan progress. It calls `events.Deliver`, which *errors*
when the event reaches nobody, so a `200` means it really arrived.
- **`restore` is slow** (~40 s in the suite) because it copies every
table. Prefer snapshotting once and restoring only when a spec
genuinely mutates state.
## Traps in the config
- **The two path keys in `.playwright/cli.config.json` resolve
differently.** `initScript` is relative to the *config file's*
directory (`"init-events.js"`, not `".playwright/init-events.js"`);
`outputDir` is relative to the *shell's cwd*. Set `outputDir` to
`".playwright-cli"` and run `playwright-cli` from the repo root, or
snapshots land somewhere neither `.gitignore` nor your next `ls`
will find, and you will read a stale one from a previous session
and think a component regressed.
- **`snapshot` writes a file, it does not print the tree.** The
command prints a path under `outputDir`; read that. Only the tail
is echoed.
- **Three separate browser caches.** `playwright-cli`, `@playwright/test`
(`make e2e-setup`) and the Vitest provider (`make ui-setup`) each
download their own Chromium. One working is no guarantee for the next.
- **`getByRole('button', { name })` matches substrings.** "Play" also
matches "Add queue to playlist"; transport controls need
`exact: true`.
- **`e2e/` is its own npm package** with `"type": "module"`. Without
that, Playwright transpiles the specs to CJS and every `import.meta`
throws — reported, unhelpfully, as "No tests found".