Issue #3606290: Add test coverage for AdvanceQueueDrainer

Frank Mablyrequested to merge
issue/orchestra-3606290:3606290-drainer-test into 1.x

Follow-up to !218 (issue #3606290): the AdvanceQueueDrainer helper added there shipped without a dedicated test. This adds one.

Covers the two guarantees the dispatcher relies on:

  • draining advances a queued run to its parked step in-request (not waiting for cron);
  • the per-call bound stops a front-end drain early, so one request never takes on the whole backlog.

Test-only, no production change.

Merge request reports