public void ExpressionlessEmptySource()
{
var numbers = new SynchronizedRangeObservableCollection <int>();
using var query = numbers.ActiveLast();
Assert.IsNotNull(query.OperationFault);
Assert.AreEqual(0, query.Value);
}
public void SourceManipulation()
{
var numbers = new SynchronizedRangeObservableCollection <int>(System.Linq.Enumerable.Range(0, 10));
using var query = numbers.ActiveLast(i => i % 3 == 0);
Assert.IsNull(query.OperationFault);
Assert.AreEqual(9, query.Value);
numbers.Remove(9);
Assert.AreEqual(6, query.Value);
numbers.RemoveAll(i => i % 3 == 0);
Assert.IsNotNull(query.OperationFault);
Assert.AreEqual(0, query.Value);
numbers.Add(30);
Assert.IsNull(query.OperationFault);
Assert.AreEqual(30, query.Value);
}