@Test
  public void whenChangeProperty1_thenProperty2ChangeReceivedByBoth() {
    PresentationModelPropertyChangeSpy spy1 =
        PresentationModelTester.spyPropertyChange(
            presentationModel, SamplePresentationModel.PROPERTY2);
    PresentationModelPropertyChangeSpy spy2 =
        PresentationModelTester.spyPropertyChange(
            presentationModel, SamplePresentationModel.PROPERTY2);

    presentationModel.changeProperty1();

    assertTrue(spy1.isPropertyChanged());
    assertTrue(spy2.isPropertyChanged());
  }
  @Test
  public void whenChangeProperty1Twice_thenProperty2ChangeReceivedTwice() {
    PresentationModelPropertyChangeSpy spy =
        PresentationModelTester.spyPropertyChange(
            presentationModel, SamplePresentationModel.PROPERTY2);

    presentationModel.changeProperty1();
    presentationModel.changeProperty1();

    assertThat(spy.getPropertyChangedCount(), is(2));
  }