Task 1 of Plan 04-08 (methodology reframe of ROADMAP SC #1): - Bundle 1.9 MB VP9 WebM fixture at tests/uat/fixtures/synthetic-display-source.webm (copy of internal Plan 01-07 fixture; CC0-equivalent project-owned) - Add globals.d.ts ambient `*.webm?url` module decl (mirrors Plan 01-10 `*.svg?url`) - Add manifest.json web_accessible_resources entry for `assets/*.webm` (iter-2 BLOCKER 1 — pre-decided to avoid executor improvisation; inert in production where dist/ has zero *.webm) - Rewrite installFakeDisplayMedia() at src/test-hooks/offscreen-hooks.ts: * Replace canvas.captureStream(30) with HTMLVideoElement.captureStream(30) — bypasses Chrome bug 653548 invisible-canvas throttling (debug session-2 root cause) * Function signature remains SYNCHRONOUS (`: void`; iter-2 BLOCKER 2 — eager-install contract preserved at lines 528-537) * Video element creation + DOM append + monkey-patch assignment execute synchronously * canplay wait + .play() deferred INTO fakeGetDisplayMedia closure (lazy first-frame pattern) * fakeVideoReadyPromise kicked off at install time so first call observes resolved Promise * WARNING 1 (autoplay reject): explicit error class identifier 'autoplay-blocked or codec-unsupported in headless context' * displaySurface monkey-patch preserved verbatim * A23 lastGetDisplayMediaConstraints capture preserved * uninstallFakeDisplayMedia teardown adapted for videoEl (pauses + removes + nulls) * All 6 bridge ops UNCHANGED in their sync return-false form - Add Tier-2 production-bundle filename-leak gate at tests/background/no-test-hooks-in-prod-bundle.test.ts (iter-2 WARNING 5 — synthetic-display-source string must be 0 hits in dist/) Verification: - npx tsc --noEmit: exit 0 - npm run build: dist/ produced; 0 *.webm files; 0 synthetic-display-source hits - npm run build:test: dist-test/assets/synthetic-display-source-mbtR1t3u.webm emitted (1.9 MB; Vite ?url asset) - Code-only grep (comment-filtered) on offscreen-hooks.ts: 0 canvas refs; 15 video refs - installFakeDisplayMedia signature unchanged: `: void` 2x; `: Promise` 0x; `await installFakeDisplayMedia` 0x - Architectural invariant unchanged: `let segments: Blob[] = []` at recorder.ts:91 (1 hit; grep gate enforces) - Tier-1 FORBIDDEN_HOOK_STRINGS unchanged at 12 entries - Tier-2 vitest gate PASSES: 14/14 GREEN under SKIP_BUILD=1 (12 Tier-1 + 1 build verify + 1 Tier-2) Per iter-3 checker advisory 1: the wrong-display-surface throw lives at recorder.ts:313-321 (not line 294 as plan text states; off by ~25 lines but unambiguous). Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Mokosh UAT harness (Plan 01-11)
Puppeteer-driven Node script that runs 14 assertions end-to-end against a real Chrome instance loaded with the Mokosh extension. Replaces Plan 01-09 Task 5's operator-empirical functional verification (the operator retains only step 1 — build — and step 14 — brand/design acceptance).
Quick start
npm run test:uat
This builds dist-test/ (the hook-enabled bundle) and runs the harness.
Exit 0 means all 14 assertions passed. Final line: UAT harness: 14/14 assertions passed.
Local-debug mode
HEADLESS=0 npm run test:uat
Opens a real Chrome window so you can watch the picker auto-accept, the badge transitions, the popup appear, etc.
Developer iteration tricks
# Skip the production build inside assertion 0 (uses existing dist/):
SKIP_PROD_REBUILD=1 npm run test:uat
# Run the harness against an existing dist-test/ (skip npm run build:test):
npx tsx tests/uat/harness.test.ts
Assertion catalog
| # | Title | Bug class | Hook used |
|---|---|---|---|
| 0 | Production bundle has no test-hook leaks | T-1-11-01 | filesystem grep |
| 1 | SW bootstrap → setIdleMode | — | sw.evaluate |
| 2 | Toolbar onClicked-idle → REC + popup | — | triggerExtensionAction |
| 3 | Offscreen displaySurface === monitor | D-15 | __mokoshTest.getCurrentStream |
| 4 | Toolbar onClicked-recording → popup, no new offscreen | — | targets count |
| 5 | SAVE_ARCHIVE → download fires | — | downloads polling |
| 6 | BUG B: simulateUserStop → badge OFF + no recovery notif | b9eeeeb |
dispatchEvent('ended') |
| 7 | RECORDING_ERROR codec-unsupported → ERR + recovery notif | — | sendMessage |
| 8 | BUG A: onStartup → mokosh-startup- notification creates | a881bf0 |
__mokoshTest.handlers.onStartup |
| 9 | Icon file sizes meet floors | Bug A precondition | sw.evaluate(fetch) |
| 10 | Manifest has notifications + 3 icons | Bug A precondition | chrome.runtime.getManifest |
| 11 | 35s recording → segments.length >= 3 | D-13 | __mokoshTest.getSegmentCount |
| 12 | ffprobe on extracted webm exits 0 | Plan 01-08 | jszip + execFile |
| 13 | Archive shape — video + meta.json version match | Plan 01-07 | jszip |
Failure isolation
Single browser, serial assertions, bail on first failure for setup- dependent assertions (assertion 0 abort means refusing to launch a potentially-leaky bundle). Per-assertion bail keeps the diagnostic output unambiguous — see RESEARCH §5 + Plan 01-11 open-question resolution 4.
On failure, the harness dumps the last 30 lines of SW console + last 30 lines of offscreen console (captured live during the run) to stderr BEFORE rethrowing — gives you contextual triage without needing to re- run with debug logging.
Known gotchas
Locale-specific picker auto-accept
The --auto-select-desktop-capture-source=Entire screen Chrome flag
auto-accepts the screen-share picker. The string "Entire screen" is
en_US-specific. If your Chrome is set to a non-English locale, the
picker option label will differ and the auto-accept will silently fail
(picker stays open; assertion 2 times out).
Fallback: switch your Chrome user-data-dir's locale to en_US for
harness runs, OR adjust the launch arg in tests/uat/lib/launch.ts to
match your locale's equivalent string.
dev-dep Chromium binary size
puppeteer pulls a ~150 MB Chromium binary at npm install time. CI
must accept this. Production npm install --omit=dev skips it cleanly.
Xvfb is NOT required
Per Plan 01-11 RESEARCH §3 empirical probes against Chrome 148, the
--headless=new mode handles screen capture without Xvfb on Linux CI
runners. If a future Chrome regresses this, Xvfb :99 & DISPLAY=:99 npm run test:uat is the fallback.
CI runner screen-capture concern
The 35s recording assertion (A11) captures whatever is on screen during that window. CI MUST run the harness in an isolated container with no concurrent workload — see T-1-11-02 in Plan 01-11's threat model.
Real Chrome download (assertion 5 → A12)
The harness configures per-page download behavior via CDP to a fresh
os.tmpdir()/mokosh-uat-downloads-* directory; downloads are NOT
written to your real ~/Downloads. The temp directory is deleted by OS
tmpdir GC.