public void TestCompareTo()
{
Optional <int> one = new Optional <int>(1);
Optional <int> two = new Optional <int>(2);
Optional <int> anotherOne = new Optional <int>(1);
Optional <int> unassignedOne = new Optional <int>();
Optional <int> unassignedTwo = Optional <int> .Unassigned;
Assert.IsTrue(one.CompareTo(two) < 0);
Assert.IsTrue(two.CompareTo(one) > 0);
Assert.IsTrue(one.CompareTo(one) == 0);
Assert.IsTrue(one.CompareTo(anotherOne) == 0);
Assert.IsTrue(one.CompareTo(unassignedTwo) > 0);
Assert.IsTrue(unassignedOne.CompareTo(unassignedTwo) == 0);
Assert.IsTrue(unassignedOne.CompareTo(one) < 0);
Assert.IsTrue(one.CompareTo(2) < 0);
Assert.IsTrue(one.CompareTo(1) == 0);
Assert.IsTrue(two.CompareTo(1) > 0);
Assert.IsTrue(unassignedOne.CompareTo(1) < 0);
}