public void ReadOnlyObservableCollection_ObserveReplaceChangedItemsTest()
{
var l = new List <OldNewPair <string[]> >();
var c = new ObservableCollection <string>(new[] { "a", "b", "c" });
var r = new ReadOnlyObservableCollection <string>(c);
r.ObserveReplaceChangedItems()
.Subscribe(x => l.Add(x));
l.Count.Is(0);
c[0] = "aaa";
l.Count.Is(1);
l[0].Is(x => x.OldItem[0] == "a" && x.NewItem[0] == "aaa");
c[2] = "ccc";
l.Count.Is(2);
l[1].Is(x => x.OldItem[0] == "c" && x.NewItem[0] == "ccc");
}
