@Override
  public void sync() {
    preferredView.sync();
    if (secondaryView != null) {
      secondaryView.sync();
    }
    errorOnPreferredView = false;
  }
@Test
  public void testSync_noSecondaryInitialized() {
    fsView.sync();
    verify(primary, times(1)).sync();
    verify(secondary, never()).sync();
  }