fix(test): eliminate race in Txn Expiration flaky test

[kriszyp]

Root cause

The Slow txn will expire test asserts trackedTxns.size === existingTxns at the end, where existingTxns was sampled before the SlowResource.get call. The problem: trackedTxns is a module-level singleton Set shared across the whole test suite. The 5 «existing» transactions sampled as the baseline are leftover open txns from earlier tests — and they can expire (and be removed from the Set by the 20ms timer) during the 50ms Promise.race window that follows, causing the count to fall below existingTxns. This produces the 0 == 5 AssertionError seen on Node v26.

The polling loop added to stabilize the baseline only checks for a 5ms quiet window; a txn whose countdown hits zero just after that window still fires in the next tick.

Fix

Replace the aggregate-count assertion with a direct membership check on lastTxn — the specific DatabaseTransaction object added by SlowResource.get(3). This is immune to other tests' txns expiring concurrently.

// before
assert.equal(trackedTxns.size, existingTxns);

// after
assert.ok(!trackedTxns.has(lastTxn), 'expected the slow transaction to have been expired and removed from trackedTxns');

Test plan

• CI passes on all three Node versions (v22, v24, v26) — the assertion is now independent of background txn churn
• The lastTxn reference was already captured unconditionally on line 52; only the final assertion changes

🤖 Generated with Claude Code

[gemini-code-assist]

Code Review

This pull request updates a transaction expiration unit test in txn-tracking.test.js to assert that a specific transaction was expired and removed, rather than asserting on the total size of tracked transactions, which was unreliable due to concurrent expirations. There are no review comments, so there is no feedback to provide.

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[claude]

Reviewed; no blockers found.