test(grants): pin the per-grant guard against a reject between read and write (TASK-333)

backend/__tests__/unit/services/roomGrantRecord.test.js

@@ -239,3 +239,27 @@ test('a close whose write fails for one grant still names the grants it did revo
   const revoked = (await chainLines()).filter((l) => l.kind === 'grant.revoked');
   expect(revoked.map((l) => l.data.grantIds)).toEqual([revokedIds]);
 });
+
+test('a reject that lands between the close\'s read and its write keeps its revocation and is not named', async () => {
+  const grant = await service.mintGrant(input());
+  const model = RoomGrant();
+  const realFindOneAndUpdate = model.findOneAndUpdate.bind(model);
+  const rejectedAt = new Date(Date.now() - 1000);
+  // The refused mint's write lands after the close read its candidates.
+  const spy = jest.spyOn(model, 'findOneAndUpdate').mockImplementationOnce(async (...args) => {
+    await model.updateOne(
+      { grantId: grant.grantId, revokedAt: null },
+      { $set: { revokedAt: rejectedAt, revocationReason: 'task.done' } },
+    );
+    return realFindOneAndUpdate(...args);
+  });
+  const logged = jest.spyOn(console, 'error').mockImplementation(() => {});
+  await close();
+  expect(spy).toHaveBeenCalledTimes(1);
+  spy.mockRestore();
+  // onTaskClosed only logs a failed close, so an empty record needs a clean close.
+  expect(logged).not.toHaveBeenCalled();
+  logged.mockRestore();
+  expect((await model.findOne({ grantId: grant.grantId }).lean()).revokedAt).toEqual(rejectedAt);
+  expect((await chainLines()).filter((l) => l.kind === 'grant.revoked')).toEqual([]);
+});