public void SourceManipulation()
{
var numbers = new SynchronizedRangeObservableCollection <int>(null, System.Linq.Enumerable.Range(0, 10).SelectMany(i => i.Repeat(5)));
using var query = numbers.ActiveDistinct();
Assert.AreEqual(0, query.GetElementFaults().Count);
Assert.AreEqual(10, query.Count);
numbers.RemoveAt(0);
Assert.AreEqual(10, query.Count);
numbers.RemoveRange(0, 4);
Assert.AreEqual(9, query.Count);
numbers.Add(10);
Assert.AreEqual(10, query.Count);
numbers.AddRange(10.Repeat(4));
Assert.AreEqual(10, query.Count);
numbers.Reset(System.Linq.Enumerable.Range(0, 5).SelectMany(i => i.Repeat(2)));
Assert.AreEqual(5, query.Count);
}