public void can_determine_if_a_property_has_changed()
{
var observable = new Observable();
var observer = new PropertyChangeObserver<Observable>(observable);
Assert.False(observer.HasChanged("Property"));
Assert.False(observer.HasChanged(x => x.Property));
observable.OnPropertyChanged("Property");
Assert.True(observer.HasChanged("Property"));
Assert.True(observer.HasChanged(x => x.Property));
}