public void PartialCloneEmptyElements()
{
int cnt = 1;
var task = new VariableArgumentTask<int> (2, (a) => cnt += a.Length);
task [0] = new PortElement<int> (10);
task [1] = new PortElement<int> (20);
var tk = task.PartialClone ();
Assert.IsNull (tk [0], "#1");
Assert.IsNull (tk [0], "#2");
}