oldRSs[i] = updatedOldRS
	}
	return oldRSs, totalScaledDown, nil
}

// scaleDownOldReplicaSetsForRollingUpdate scales down old replica sets when deployment strategy is "RollingUpdate".
// Need check maxUnavailable to ensure availability
func (dc *DeploymentController) scaleDownOldReplicaSetsForRollingUpdate(ctx context.Context, allRSs []*apps.ReplicaSet, oldRSs []*apps.ReplicaSet, deployment *apps.Deployment) (int32, error) {

		controller := &DeploymentController{
			client:        &fakeClientset,
			eventRecorder: &record.FakeRecorder{},
		}
		_, ctx := ktesting.NewTestContext(t)
		scaled, err := controller.scaleDownOldReplicaSetsForRollingUpdate(ctx, allRSs, oldRSs, deployment)
		if err != nil {
			t.Errorf("unexpected error: %v", err)
			continue
		}
		if !test.scaleExpected {
			if scaled != 0 {