social test: face-rooms pins local-time titles to UTC strings, so the file is red on every non-UTC machine #3106

Implementation: FlyBot (ours) — PR follows within 24h. Do not pick up without a pickup-ok comment on this issue.

Written-by: FlyBot Lead
Claimed-by: FlyBot Lead
Claim-Id: b8416b79222d43199c9183fce882b342
Branch: dev/1-face-when-local-tz
Base: 5cb1692
At: 2026-11-15T08:38:28Z

Implementation: FlyBot (ours) — PR follows within 24h. Do not pick up without a pickup-ok comment on this issue.

Written-by: FlyBot Lead
Bot: FlyBot Dev-1

What goes wrong

plugins/social/test/face-rooms.test.js pins a local-time render to fixed UTC strings. faceRoomTitle formats through core/src/shared/face-title.js formatFaceWhen, which reads the host's local zone (date.getHours(), getMinutes(), getMonth(), getDate()), so the same instant renders differently per zone — and only TZ=UTC produces the strings the test expects:

Two assertions on live main 5cb16923 therefore go red on any machine that is not in UTC — for a rendering that is correct:

• :250 const at = '2026-10-17T14:38:00.000Z' → :254 expects Face-to-face · UiA1415, UiB1415 · Oct 17 14:38.
• #194 case at :644: :646/:647 expiresAt: '2026-10-17T13:06:00.000Z' with :649 expecting /12:56$/, and :650/:651 createdAt: '2026-10-17T12:40:00.000Z'.

Red first, base 5cb16923, plugins/social → node --import ./test/resolve.mjs --test test/face-rooms.test.js (38 tests, 36 pass / 2 fail in both zones):

TZ=Asia/Shanghai
not ok 9 - owner-typed face-room lines encode as a human envelope
    + 'Face-to-face · UiA1415, UiB1415 · Oct 17 22:38'
    - 'Face-to-face · UiA1415, UiB1415 · Oct 17 14:38'
not ok 28 - #194: a face room title shows one time, the creation time, before and after Enter chat
    The input did not match the regular expression /12:56$/. Input:
    'Face-to-face · Alice · Oct 17 20:56'

TZ=America/New_York  → same two, actual `… · Oct 17 10:38` and `'Face-to-face · Alice · Oct 17 08:56'`

Different offsets, same class of failure: the expectation is tied to the host zone, not to an offset bug.

Expected

The tests keep asserting exactly what they assert today — the title carries the room's local creation time, and two rooms with the same owners stay distinguishable — but pass in every zone:

• build the fixture instants from local components (new Date(2026, 9, 17, 14, 38).toISOString()), so Oct 17 14:38 and /12:56$/ hold everywhere; or
• assert against formatFaceWhen(at) computed in the same process.

Expectations stay exact: no tolerance window, no regex that accepts any hour, no skip/todo, and the neighbouring assertions (:253 titleA === titleB, :255-262, :257-260 two different starts must still differ) unchanged. The test must not become vacuous.

Scope

• Test only: plugins/social/test/face-rooms.test.js (+ its byte-identical mirror if this file keeps one).
• No product change: core/src/shared/face-title.js / plugins/social/src/face-rooms.js keep formatting in local time.
• T1 (test-only diff), no user-visible behaviour change. plugins/social/test/** maps to docs/subsystems/social.md; test-only, so the commit carries a Docs-not-needed: trailer rather than a doc edit.

Acceptance

1. Red on the base in a non-UTC zone (above, two zones, same class).
2. Green after the change in TZ=UTC, TZ=Asia/Shanghai, TZ=Europe/Berlin, twice each, 38/38 every run.
3. Whole social package green in a non-UTC zone (TZ=Asia/Shanghai npm --prefix plugins/social test, 701/701), and npm run verify exit 0.
4. No third hard-coded local render left in the same file.

Out of scope (checked, not changed)

plugins/social/test/social.test.js:4076/:4086 carries the same literal but is not red: shownFaceTitle reuses the timestamp stored in room.name (storedWhen → faceStamp) instead of re-deriving local time — 492/492 under TZ=Asia/Shanghai.

Dedupe (2026-11-15, live main 5cb16923)

• git grep on live main: the only getHours()-formatted assertions in plugins/social/test/ are the two fixed here.
• Issue search, open and closed on repo:ThinkFlowLab/FlyBot: face-rooms timezone, face-rooms UTC, formatFaceWhen, test local time — no hit. Near matches are unrelated: a Date.now() race in room-invite-preview.test.js (Test flake: room-invite-preview compares a rendered countdown against a second Date.now(), losing a second at the boundary #1839), unknown timeZone validation (An unknown timeZone in one project-read request throws out of the whole Project board, not just the metrics block #1849).
• File sha at that tree: 8bae984a066c56f7b5648953486cd18db76055a7.