- Add blobToBase64 / base64ToBlob in src/shared/binary.ts:
portable Blob↔base64 round-trip for the chrome.runtime.Port
wire-format. JSON.stringify(blob) returns "{}" across extension
contexts, so binary payloads must travel as base64 strings.
- Mirror the GREEN-block helper signatures from
tests/offscreen/port-serialization.test.ts so the same test pins
both the standalone helpers and the production wire format.
- Land tests/offscreen/port-serialization.test.ts as the RED+GREEN
executable contract for the D-12 fix: the RED block reproduces
the 75-byte "[object Object]" failure mode byte-for-byte; the
GREEN block pins the base64 wire-format the fix must implement.
- Uses arrayBuffer() + btoa(String.fromCharCode...) rather than
FileReader: FileReader is browser-only; the chosen approach
works in both Chrome extension contexts and the Node-based
vitest environment.
Refs: debug session d12-blob-port-transfer-fails.
Three RED tests pin Pattern 4 (handshake) and Pattern 5 / Pitfall 4
(port reconnect on disconnect) contracts:
handshake.test.ts:
- 'sends OFFSCREEN_READY after listener registration' — exactly one
OFFSCREEN_READY emitted at module load, AFTER onMessage.addListener
port.test.ts:
- 'connects on module load' — chrome.runtime.connect called once
- 'reconnects when port disconnects' — firing onDisconnect triggers
immediate re-connect (Pitfall 4 idle-timer reset)
chrome.runtime is stubbed locally (no vitest-chrome dependency added).
No 'as any' / no '@ts-ignore'; casts are 'as unknown as T'.
Plan 04 must wire OFFSCREEN_READY send + port.connect({ name:
'video-keepalive' }) + onDisconnect-driven reconnect at the import-side
effect layer of src/offscreen/recorder.ts.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Two RED tests pin D-20 (codec strict-mode, no silent fallback):
- 'throws on unsupported vp9 and emits RECORDING_ERROR'
- 'does not throw when vp9 IS supported'
vi.resetModules() between tests is critical: module-load side-effects
(handshake + port connect) happen once per import, so isolation across
the four test files depends on it.
chrome.runtime is stubbed locally (no vitest-chrome dependency added,
per threat T-1-NEW-02-01 — minimize supply chain for four test files).
No 'as any' / no '@ts-ignore'; the cast is 'as unknown as T'.
Plan 03 must export assertCodecSupported() from src/offscreen/recorder.ts.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Four RED tests pin D-10 (header pinning) and D-11 (30s trim) contracts:
- 'first chunk is header' — isFirst marker on first addChunk
- 'second chunk is NOT header' — only the first is pinned
- 'trim 30s — keeps header, evicts aged tail' — header survives indefinitely
- 'trim with empty buffer does not throw' — defensive edge case
Plan 03 must export {addChunk, trimAged, getBuffer, resetBuffer} from
src/offscreen/recorder.ts to flip these to GREEN.
Also stages tests/fixtures/.gitkeep so the fixture dir survives clean
checkouts (Plan 07 drops a known-good last_30sec.webm into it after the
manual smoke test).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
