Worker tests: hold D417 and D124 to the clock the code reads (#1342)

[guillaumelauzier]

Objective

Two Worker test files went wrong when a run crossed midnight UTC: D417 failed and D124 stopped catching the bug it guards. PR #1329's test:drift (23:58 to 00:02 UTC) failed on D417. This PR holds each file to the clock its code reads. Test files only: no route change, no decision, no migration.

Closes #1342

Implementation

• entity_obligations_d417.test.ts. TODAY was a module constant, fixed when the file loaded, while legal_entities.ts reads new Date() on every request.
  • A beforeEach now freezes the JS Date at the real instant each test starts (mock.timers.enable({ apis: ['Date'] })), and an afterEach resets it.
  • today() and plusDays() read that clock when called.
  • So the fixture's dates and the route's today() agree, even if midnight passes during a test.
  • Only Date is mocked; timers and SQLite's clock are untouched. Every assertion is unchanged.
• expiry_gate_datetime_d124.test.ts. expiredIso pins the spent row to SQLite's date when the row is written; the gate reads datetime('now') when it runs.
  • Across midnight, that row is on yesterday's date, where even the broken bare comparison is right. The tests still passed, but they no longer tested anything.
  • The six behavioural tests now run through onOneUtcDay. It records each expired fixture's day, re-reads SQLite's date after the last assertion, and runs a body that straddled midnight once more on the new day.
  • If the date moves during both runs, the test fails.
  • _timeFixture.mjs is not touched; it is outside this task's files.

Files changed

• cloudflare-worker/test/entity_obligations_d417.test.ts
• cloudflare-worker/test/expiry_gate_datetime_d124.test.ts

Testing

• npm run build, then npm run test:drift > drift.log 2>&1; echo EXIT=$? → EXIT=0 (Worker 5,994, frontend 5,151, retention 127).
• The clock across midnight, with faketime (libfaketime), which moves both the JS clock and SQLite's.

  • D417, started at 23:59:50 to 23:59:59 UTC at ×10 speed, so midnight falls between the file's tests:

    • before the fix, starts at 23:59:54, :55 and :56 failed 3, 4 and 5 tests (days_left, resolved_on, as_of);
    • after it, every start passes 15 of 15.

    TZ=UTC faketime -f '@2026-10-07 23:59:55 x10' node --experimental-strip-types --no-warnings \
      --import ./cloudflare-worker/test/_ts-loader.mjs --test cloudflare-worker/test/entity_obligations_d417.test.ts

  • D124, started at 23:59:59 UTC. A preload shim holds the first expired-fixture read for 1.2 s, so the first test writes its spent row on 10-07 and runs the gate on 10-08 (the shim logs fixture read 2026-10-07 23:59:59, now 2026-10-08 00:00:00).

    Gate	Old test	New test
    fixed	7 of 7 pass	7 of 7 pass
    broken (bare expires_at > datetime('now') in the magic-link gate)	only the static shape test fails; the behavioural test misses it	the behavioural test and the shape test fail

    The shim

    import { DatabaseSync } from 'node:sqlite';
    const orig = DatabaseSync.prototype.prepare;
    let held = false;
    DatabaseSync.prototype.prepare = function (sql, ...rest) {
      const stmt = orig.call(this, sql, ...rest);
      if (!held && /SELECT date\('now'\) AS day, datetime\('now'\) AS now/.test(sql)) {
        const get = stmt.get.bind(stmt);
        stmt.get = (...a) => {
          const row = get(...a);
          held = true;
          Atomics.wait(new Int32Array(new SharedArrayBuffer(4)), 0, 0, 1200);
          return row;
        };
      }
      return stmt;
    };

    Run with TZ=UTC faketime -f '@2026-10-07 23:59:59' node … --import ./midnight-shim.mjs --test …d124.test.ts.

• Mutation checks, both ways:
  • D417:
    • daysUntil off by one: 5 tests fail, at the real time and under the ×10 shim at 23:59:55;
    • the route's today() reading yesterday: 4 tests fail.
    • Restored: 15 of 15 pass. Freezing the clock does not hide a route that reads the wrong day.
  • D124: the bare magic-link comparison fails test 1 (and the shape test), at the real time and across midnight. Restored: 7 of 7 pass.

Risks

• Test-only. Nothing ships to the Worker.
• mock.timers with Date is in Node 22 (the CI version). It mocks Date only during each D417 test, and resets after.

Dependencies

• Found while reviewing D611: colleague seat invites reach the colleague #1329.

Agent

S10 · Claude Code

Review requested

Any agent.

STATUS
task: #1342   slot: S10   agent: claude
branch: agent/claude/1342-midnight-date-tests
state: READY_FOR_REVIEW
files: cloudflare-worker/test/entity_obligations_d417.test.ts, cloudflare-worker/test/expiry_gate_datetime_d124.test.ts
blockers: none
questions: none
tests: npm run build, then npm run test:drift → EXIT=0; faketime across midnight: D417 passes at every start, D124 now catches a broken gate across midnight; mutants caught both ways
pr: (this PR)

🤖 Generated with Claude Code

https://claude.ai/code/session_01VCuRYkf1et4rs1gQ9QWFwR

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Generated by Claude Code

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