public void TryAddTest()
{
IWDT iwdt = new IWDT();
Assert.IsTrue(iwdt.TryAdd(HT(1, 1), 4));
Assert.AreEqual(4, iwdt.GetItem(HT(1, 2)));
Assert.IsFalse(iwdt.TryAdd(HT(1, 3), 8));
iwdt.Keys[Tuple.Create(1, 1)].IsGarbage = true;
Assert.IsTrue(iwdt.TryAdd(HT(1, 3), 8));
Assert.AreEqual(8, iwdt.GetItem(HT(1, 2)));
}