SPIKE OUTCOME: FAILED (offscreen DIED across 5-min SW idle + worker.close())
Per Plan 04-04 spike-first contract, Wave 0 empirically investigated whether
the offscreen document's RAM-only `segments: Blob[] = []` at
src/offscreen/recorder.ts:91 survives a 5-min SW idle followed by Puppeteer
CDP-driven `worker.close()`. RESEARCH Q2 hypothesis (MEDIUM confidence): yes,
the offscreen has its own lifecycle anchored by active MediaRecorder. Spike
result REFUTES that hypothesis.
Empirical measurement (HEADLESS=1; one full run; reproducible via the
committed spike script):
- assertA2 priming: PASSED (badge=REC; offscreen + MediaRecorder live)
- 5-min idle: elapsed cleanly (308.7s total wall-clock)
- stopServiceWorker: succeeded (worker.close() returned)
- SAVE_ARCHIVE ack: {success: true} (SW respawned + processed message)
- video/last_30sec.webm size: 8505 bytes (well below 100 KB floor)
- meta.urls: only chrome-extension://* origins; real-page URLs LOST
- rrweb/session.json: []
- logs/events.json: []
- ffprobe on extracted webm: 'End of file' + 'Duplicate element' errors
(corrupt/truncated; not a valid 30s segment cluster sequence)
Interpretation: offscreen-document lifecycle is NOT independent of the SW
under Puppeteer CDP-driven worker.close() conditions. The 8505 bytes are
likely stale/partial header bytes from a re-initialized empty offscreen
context after SW respawn, not a surviving 30s buffer. The plan's Task 2
GATING CONDITION (videoSize > 100_000) is NOT satisfied; Task 2 is BLOCKED.
Per saved memory `feedback-gsd-ceremony-for-fixes.md`: architectural changes
(moving segments from offscreen RAM to IndexedDB per RESEARCH Q2 sub-question
b Option C) MUST route through proper plan-fix ceremony, NOT improvised
inline inside Plan 04-04. Plan 04-04 SUMMARY flags the failure mode + cites
exact remediation path. ROADMAP SC #1 remains OPEN pending the persistence-
layer plan-fix.
Task 1 persisting artifacts (this commit):
- tests/uat/lib/harness-page-driver.ts:
+ Browser type import (puppeteer)
+ stopServiceWorker(browser, extensionId) helper (verbatim from Chrome
devrel canonical pattern — Puppeteer >=22.1.0; project pin ^25 OK)
+ findLatestZip exported (was module-internal) so the spike script can
reuse the canonical mtime-sort selection logic without duplication
- tests/uat/spike-a33-sw-persistence.ts (NEW):
+ One-shot empirical investigation script; reusable for future SW-
lifecycle regression testing (e.g., verifying the eventual IndexedDB
persistence layer actually closes ROADMAP SC #1)
+ Step 1 reuses __mokoshHarness.assertA2 (canonical fresh-recording
prime; not the non-existent dispatchSaveArchive that REVISION iter-2
explicitly forbids)
+ Step 5 dispatches SAVE_ARCHIVE via chrome.runtime.sendMessage inline
from harness-page realm (Option B per plan-checker BLOCKER 2;
matches A5/A11/A12/A13/A26/A28/A29/A30/A31 pattern)
Verification (Task 1 acceptance criteria):
- npx tsc --noEmit: exits 0
- HEADLESS=1 tsx tests/uat/spike-a33-sw-persistence.ts: ran to completion
(no Puppeteer throw); SPIKE RESULT line emitted with explicit
videoSize=8505 bytes; SAVE_ARCHIVE ack received
- grep -c 'dispatchSaveArchive' tests/uat/spike-a33-sw-persistence.ts: 0
- grep -c "type: 'SAVE_ARCHIVE'" tests/uat/spike-a33-sw-persistence.ts: 1
- Total spike wall-clock: 308.7s (~5min idle + ~8s orchestration)
References:
- Plan 04-04 PLAN.md spike contract (lines 64-72)
- 04-RESEARCH.md Q2 sub-question (b) — Chrome MV3 offscreen lifecycle
- https://developer.chrome.com/docs/extensions/how-to/test/test-serviceworker-termination-with-puppeteer
- Saved memory: feedback-gsd-ceremony-for-fixes.md (no inline architectural
fixes; route through plan-fix ceremony)
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.