public void ExpressionlessSourceManipulation()
{
var numbers = new SynchronizedRangeObservableCollection <decimal>();
using var aggregate = numbers.ActiveAverage();
Assert.IsNotNull(aggregate.OperationFault);
Assert.AreEqual(0, aggregate.Value);
numbers.Add(1m);
Assert.IsNull(aggregate.OperationFault);
Assert.AreEqual(1m, aggregate.Value);
numbers.AddRange(System.Linq.Enumerable.Range(2, 3).Select(i => Convert.ToDecimal(i)));
Assert.AreEqual(2.5m, aggregate.Value);
numbers.RemoveRange(0, 2);
Assert.AreEqual(3.5m, aggregate.Value);
numbers.RemoveAt(0);
Assert.AreEqual(4m, aggregate.Value);
numbers.RemoveAt(0);
Assert.IsNotNull(aggregate.OperationFault);
Assert.AreEqual(0m, aggregate.Value);
numbers.Reset(System.Linq.Enumerable.Range(2, 3).Select(i => Convert.ToDecimal(i)));
Assert.IsNull(aggregate.OperationFault);
Assert.AreEqual(3m, aggregate.Value);
}