Browser-level tests for the parts that unit tests cannot reach: which <video> the extension picks on a real page, and whether the packed extension gets far enough to control it.

npm run test:e2e:install   # once, downloads the browsers
npm run build:extension    # extension.spec.mjs loads dist/chrome
npm run test:e2e
npm run test:e2e:detection # finder only: Chromium, Firefox, WebKit
npm run test:e2e:extension # packed extension only: Chromium MV3
npm run test:e2e:race      # @race scenarios, repeated 20 times

Layout

Path	Purpose
`detection.spec.mjs`	Runs the shipped `findVideo()` against the fixture pages
`extension.spec.mjs`	Loads `dist/chrome`, injects into a tab, applies remote play/pause/seek
`room-sync.spec.mjs`	Starts a local relay and proves two packed clients, relay restart, and MV3 worker recovery
`popup-accessibility.spec.mjs`	Checks visible control names and keyboard tab activation in the real popup
`global-setup.mjs`	Owns the fixture server for the complete Playwright run and closes it during teardown
`fixture-server.mjs`	Static server for the fixtures, with byte-range support for media
`fixtures/pages/`	One page per scenario
`fixtures/media/`	Small generated clips (see below)
`helpers/content-source.mjs`	Lifts the real finder out of `extension/content.js`

The detection fixtures run as three Playwright projects: Chromium, Firefox, and WebKit. Packed-extension tests remain Chromium-only because they exercise Chrome MV3 APIs and a persistent service-worker context. The scheduled .github/workflows/race-tests.yml lane repeats tests marked @race and uploads traces/results on failure.

Locally, global setup reuses an already running fixture server on the configured port. CI always owns a fresh server so a port collision fails instead of testing against an unknown process. Keeping the server inside Playwright's lifecycle also prevents an orphaned node process from blocking teardown on Windows.

Two rules worth keeping

The specs run the shipped source, not a copy. helpers/content-source.mjs extracts findVideo and its ranking helpers straight out of extension/content.js. A fixture that passes against a reimplementation would prove nothing about the extension. If you split the finder into more functions, add them to VIDEO_FINDER_EXPORTS there and to VIDEO_FINDER_PARTS in scripts/test-content-video-finder.cjs, or the extraction fails loudly.

Each fixture marks its own answer. The element that must win carries data-expected; videos that have to be playing carry data-autoplay, and ready.js holds the page back until metadata and playback have settled. The specs assert those preconditions before judging the finder, so a broken fixture reads as a broken fixture instead of a scoring regression.

Scenarios

Fixture	What it pins down
`simple-player.html`	The ordinary case
`iframe-player.html`	Player inside a same-origin frame, empty top document
`late-frame.html`	Player frame attached after the page settled
`shadow-player.html`	Player in a shadow root, tiny teaser in the light DOM
`muted-player.html`	Mute must not disqualify the only player
`display-contents-player.html`	A visible player survives a boxless `display: contents` wrapper
`hidden-preload.html`	A `display:none` preload still reports 1080p; it must lose
`ad-frame.html`	1080p asset in a 300x250 ad slot must lose to the real player
`background-loop.html`	Silent looping hero must lose despite being the largest
`multi-player.html`	Between equal players, the playing one wins
`sourceless.html`	A large `<video>` with no source can never be the player
`nested-frame.html`	Player two frame levels down
`reloading-frame.html`	Frame that swaps its document, with no mutation in the top one

Benchmark

bench-finder.mjs is not a spec, because timings are machine dependent and would only add noise to CI. Run it by hand when the finder changes:

node tests/e2e/fixture-server.mjs 4173 & node tests/e2e/bench-finder.mjs

It measures the shipped finder (lifted from content.js) against the pre-v3.1.0 formula, which is transcribed inside the script since that code no longer exists in the tree.

Regenerating the media

Solid-colour clips, a few KB each, committed so the suite needs no network:

ffmpeg -y -f lavfi -i "color=c=blue:s=1920x1080:d=30:r=10" -c:v libx264 -preset veryfast -crf 45 -pix_fmt yuv420p -movflags +faststart fixtures/media/player-1080p-30s.mp4

Same command with green/854x480/12, red/640x360/5 and gray/1280x720/3 for the other three.