Smells:

scheduler_test.go:144:146

	// Wait some time to pickup work and finish.
	// We have to wait at least 3 seconds for scheduler tick interval.
	time.Sleep(5 * time.Second)

This just failed with the error that the job is in an invalid status. I think this should be fortified or it will cause problems in the future. The scheduler needs to be tested in a different way, or manually kicked off at this stage, or somehow signal on a channel that it's done with its round.