public void Count_reflects_changes()
{
var lbs = new ListBehaviorSubject <int>();
lbs.OnAdd(1);
lbs.OnAdd(2);
lbs.OnAdd(3);
var count = 0;
var sub = lbs.Count().Subscribe(Observer.Create <int>(newCount => count = newCount));
Assert.AreEqual(3, count);
lbs.OnRemove(0);
Assert.AreEqual(2, count);
lbs[0] = 5;
Assert.AreEqual(2, count);
lbs.OnClear();
Assert.AreEqual(0, count);
sub.Dispose();
lbs.OnAdd(41);
Assert.AreEqual(0, count);
}