public void TestAdd() { Cartesian original = new Cartesian(10.0, 20.0, 30.0); Cartesian toAdd = new Cartesian(1.0, 2.0, 3.0); Cartesian result = original + toAdd; Assert.AreEqual(11.0, result.X); Assert.AreEqual(22.0, result.Y); Assert.AreEqual(33.0, result.Z); result = original.Add(toAdd); Assert.AreEqual(11.0, result.X); Assert.AreEqual(22.0, result.Y); Assert.AreEqual(33.0, result.Z); }