public void Contains_ObservableSourceElementAdded_Update()
{
var update = false;
var coll = new ObservableCollection <int>()
{
1, 2, 3
};
INotifyEnumerable <int> notifiable = coll.WithUpdates();
var test = Observable.Expression(() => notifiable.Contains <int>(4));
test.ValueChanged += (o, e) =>
{
update = true;
Assert.IsFalse((bool)e.OldValue);
Assert.IsTrue((bool)e.NewValue);
};
Assert.IsFalse(test.Value);
Assert.IsFalse(update);
coll.Add(4);
Assert.IsTrue(update);
Assert.IsTrue(test.Value);
}