protected void showModel(EpoxyModel<?> model, boolean show) {
    if (model.isShown() == show) {
      return;
    }

    model.show(show);
    notifyModelChanged(model);
  }
@Test
  public void testShowModel() {
    TestModel testModel = new TestModel();
    testModel.hide();
    testAdapter.addModels(testModel);

    testAdapter.showModel(testModel);
    verify(observer).onItemRangeChanged(0, 1, null);
    assertTrue(testModel.isShown());

    checkDifferState();
  }