public void TestForMultipleElements()
{
var p = new Port<int> ();
p.Post (33);
p.Post (55);
p.Post (44);
IPortElement[] res = p.TestForMultipleElements (2);
Assert.IsNotNull (res, "#1");
Assert.AreEqual (2, res.Length, "#2");
Assert.AreEqual (1, p.ItemCount, "#3");
Assert.AreEqual (33, res [0].Item, "#4");
Assert.AreEqual (55, res [1].Item, "#5");
res = p.TestForMultipleElements (2);
Assert.IsNull (res, "#6");
Assert.AreEqual (1, p.ItemCount, "#7");
}