public void CompareToTest()
 {
     Assert.AreEqual(true, p1.CompareTo(null) > 0);
     Assert.AreEqual(true, p1.CompareTo(p2) > 0);
     Assert.AreEqual(true, p2.CompareTo(p1) < 0);
     Assert.AreEqual(true, p1.CompareTo(p1) == 0);
     Assert.AreEqual(true, p2.CompareTo(p2) == 0);
 }