public void RandomlyChangeIndex() { RandomGenerator.ResetRandomGenerator(); var list = new ObservableList <int>(); foreach (var value in Enumerable.Range(0, 100)) { list.Add(list.Count, RandomGenerator.GenerateRandomInteger()); } var index = new ActiveValue <int>(); var sut = list.ActiveElementAtOrDefault(index); foreach (var value in Enumerable.Range(0, 100)) { index.Value = RandomGenerator.GenerateRandomInteger(-10, 110); Assert.Equal(sut.Value, list.ElementAtOrDefault(index.Value)); } }