signalk-server-e2e

End-to-end test a SignalK server or plugin change in a real browser

When a change touches server behavior a unit test can't reach — Admin UI, a plugin's config panel, data reaching Freeboard-SK, the delta/stream path — verify it in a real browser against a running server before you open the PR. This is the browser-level complement to the server's own npm test; it catches the "serves fine but the UI never shows it" class of bug that mocked tests miss.

This skill is the SignalK-specific layer. The shared browser mechanics live in the companion webapp-e2e skill (always installed alongside this one): using the repo's bundled @playwright/test chromium instead of a system/MCP browser, role/label locators + auto-waiting expect, mounting a Module-Federation component, the headless-Chrome blank-canvas gotcha, and the PR-evidence gating. Read webapp-e2e for those; below is only what's specific to a SignalK server.

1. Spin up the server under test

Start a real server on a throwaway config dir so you never touch a live install:

# from the signalk-server checkout; -c points at a scratch data dir
mkdir -p /tmp/sk-e2e
PORT=4000 npm start -- -c /tmp/sk-e2e &
SK_PID=$!

• Readiness gate: poll an HTTP endpoint until it answers (GET /signalk returns 200) before launching the browser — "process started" ≠ "server answering". Make this fetch-poll the primary gate; a SignalK UI holds its delta WebSocket open, so page.goto(..., { waitUntil: "networkidle" }) may never fire and is only a fallback for the page load itself.

  for (let i = 0; i < 60; i++) {
    try { if ((await fetch("http://localhost:4000/signalk")).ok) break; } catch {}
    await new Promise((r) => setTimeout(r, 500));
  }
  

• Plugin under test: symlink your plugin into the server's node_modules (or npm i it as a file: dep) so a npm run build in the plugin dir is picked up on the next server restart — no npm link dance. Rebuild the plugin, restart the server, then run the browser check.

• Security: with security disabled (fresh scratch config) the /signalk/v1/stream WebSocket accepts unauthenticated deltas and the resource/data APIs are anonymously readable — which is what makes headless e2e cheap. If you must test an admin-gated path, log in through the UI in the Playwright script and reuse the storage state.

• Teardown: always kill the server and remove the scratch dir when done, even on failure, so a wedged :4000 or a stale config doesn't poison the next run: