public void Items_removed_by_index_from_the_binding_list_are_removed_from_the_ObservableHashSet()
        {
            var item = new ListElement(4);
            var oc   = new ObservableHashSet <ListElement> {
                3, 1, item, 1, 5, 9
            };
            var obbl = new ObservableBackedBindingList <ListElement>(oc);

            obbl.RemoveAt(2);

            Assert.False(oc.Contains(item));
        }
    public void Items_removed_by_index_from_the_binding_list_are_removed_from_the_ObservableCollection()
    {
        var item = new ListElement(4);
        var oc   = new ObservableCollection <ListElement>
        {
            3,
            1,
            item,
            1,
            5,
            9
        };
        var obbl = new ObservableBackedBindingList <ListElement>(oc);

        obbl.RemoveAt(2);

        Assert.DoesNotContain(item, oc);
    }