public void ReadOnlyCollection_ObserveAddChangedItemsTest() { var l = new List <string[]>(); var c = new ObservableCollection <string>(); var r = new ReadOnlyObservableCollection <string>(c); r.ObserveAddChangedItems() .Subscribe(x => l.Add(x)); l.Count.Is(0); c.Add("a"); l.Count.Is(1); c.Add("b"); l.Count.Is(2); l[0].Is("a"); l[1].Is("b"); }