public void ReadOnlyObservableCollectionCount()
{
var ints = new ObservableCollection <int>();
var source = new ReadOnlyObservableCollection <int>(ints);
var changes = new List <EventPattern <PropertyChangedAndValueEventArgs <int> > >();
using (source.ObservePropertyChangedWithValue(x => x.Count, signalInitial: false)
.Subscribe(x => changes.Add(x)))
{
CollectionAssert.IsEmpty(changes);
ints.Add(1);
EventPatternAssert.AreEqual(source, "Count", Maybe <int> .Some(1), changes.Single());
ints.Add(2);
Assert.AreEqual(2, changes.Count);
EventPatternAssert.AreEqual(source, "Count", Maybe <int> .Some(2), changes.Last());
}
}
