The test kit

dist/testkit.cjs, for a game’s headless tests in Node. It drives Chromium through the game’s own Playwright, or through puppeteer-core with the Chrome in $CHROME (as CI’s browser-actions/setup-chrome provides); $TYCHO_DRIVER picks one.

const tk = require('../vendor/tycho/dist/testkit.cjs');
const kit = await tk.launch({ gl: true });             // gl: WebGL2 in software; without, the GPU is off
const { page, errors } = await tk.open(kit, {
  root: ROOT,                                          // the game's folder, opened from a file...
  serve: true,                                         // ...or served over http
  viewport: tk.PHONE_WIDE,                             // PHONE, PHONE_WIDE, DESKTOP, or { width, height, mobile, scale }
  storage: null,                                       // start with empty localStorage (or { key: value })
  ready: 'typeof Game !== "undefined" && Game.ready',  // an expression or a function run in the page
});
await tk.waitFor(page, () => Game.frame > 10);
await tk.shot(page, OUT, 'phone-start');
tk.finish('smoke', failures);                          // prints the verdict, exits 1 on failure
await kit.close();

Name	What it does
`launch({ gl, args, driver })`	A browser: `{ driver, browser, page(viewport), close() }`. Each page is in a context of its own on both drivers, so nothing one page stored (a save written as it closed) reaches the next
`serve(root, routes)`	Serves a folder on a free port (`version.json` answers a local build)
`open(kit, options)`	A fresh page on the game, errors gathered, storage set, ready waited for
`waitFor(page, test, { timeout, every, arg })`	Polls until true, the same under either driver
`errorsOf(page)`	Page errors and console errors, as they come
`shot(page, dir, name)`	A screenshot
`golden(file, values, { update })`	Compares name/value pairs with a JSON file; `--update` writes it
`PAGE`	Helpers to put in a page (`page.evaluate(tk.PAGE)`): `TK.hash(bytes)`, `TK.canvas(c)`, `TK.image(img)`
`diff(kit, pngA, pngB, { tone })`	Compares two pictures tone by tone: `{ same, maxTone, share, mean }`
`finish(name, failures)`	The verdict (failures are annotations under GitHub Actions)
`run(name, body)`	Runs an async body returning failures; a crash is a failure too