Context

Issue #1603 added tokio::select! in run_scheduler_loop() to poll channel.recv() concurrently with scheduler.wait_event(). Non-cancel messages received during plan execution are queued via enqueue_or_merge().

Missing test (COV-03)

There is no integration test that verifies this queuing behavior end-to-end: that a non-cancel message delivered to the channel during scheduler loop execution appears in message_queue after the plan completes.

The enqueue_or_merge() unit tests in message_queue.rs cover the queue logic in isolation, but not the scheduler loop path.

Acceptance criteria

• A #[tokio::test] in agent/tests.rs that:
  1. Builds an agent with a MockChannel pre-loaded with a non-cancel message (e.g. "hello")
  2. Runs the scheduler with a graph that completes on the first tick
  3. Asserts that agent.message_queue contains the queued message after plan completion

Labels

enhancement, testing