[JUnit] Either validate or ignore public helper methods in mixin superclass ... (was resulting in mixin not rendering, even though was in metamodel)

 @RequiredArgsConstructor
public abstract class UpdateTimeWindow {
  private final BaseEntity baseEntity;

  public abstract TimeWindow getTimeWindow();  // <<<<<<<<<<< PROBLEMATIC...
  public abstract void initTimeWindow();       // <<<<<<<<<<<

  public BaseEntity act(String startTime, String endTime) {
    if (getTimeWindow() == null) {
      initTimeWindow();
    }
    getTimeWindow().setValue(startTime, endTime);
    return baseEntity;
  }

public class UpdateAdvanceDeliveryTimeWindow extends UpdateTimeWindow {
    public UpdateAdvanceDeliveryTimeWindow() {
        super(Client.this);
    }
    public BaseEntity act(String startTime, String endTime) { return super.act(startTime, endTime); }
    public TimeWindow getTimeWindow() {
        return Client.this.getAdvanceDeliveryTimeWindow();
    }
    public void initTimeWindow() {
        advanceDeliveryTimeWindow = new TimeWindow();
    }
}