public void ExpressionlessSourceManipulation()
{
var numbers = new SynchronizedRangeObservableCollection <int>();
using var aggregate = numbers.ActiveSum();
Assert.IsNull(aggregate.OperationFault);
Assert.AreEqual(0, aggregate.Value);
numbers.Add(1);
Assert.IsNull(aggregate.OperationFault);
Assert.AreEqual(1, aggregate.Value);
numbers.AddRange(System.Linq.Enumerable.Range(2, 3));
Assert.AreEqual(10, aggregate.Value);
numbers.RemoveRange(0, 2);
Assert.AreEqual(7, aggregate.Value);
numbers.RemoveAt(0);
Assert.AreEqual(4, aggregate.Value);
numbers.Reset(System.Linq.Enumerable.Range(1, 3));
Assert.AreEqual(6, aggregate.Value);
}