public void ReadOnlyObservableCollectionCount()
{
var ints = new ObservableCollection <int>();
var source = new ReadOnlyObservableCollection <int>(ints);
var changes = new List <EventPattern <PropertyChangedEventArgs> >();
using (source.ObservePropertyChanged(x => x.Count, signalInitial: false)
.Subscribe(x => changes.Add(x)))
{
CollectionAssert.IsEmpty(changes);
ints.Add(1);
Assert.AreEqual(1, changes.Count);
Assert.AreEqual("Count", changes.Single().EventArgs.PropertyName);
Assert.AreSame(source, changes.Single().Sender);
ints.Add(2);
Assert.AreEqual(2, changes.Count);
Assert.AreEqual("Count", changes.Last().EventArgs.PropertyName);
Assert.AreSame(source, changes.Last().Sender);
}
}
