public void Problem1_PointClass_SideAffecting()
        {
            // Instantiate the problem
            var target = new Problem1();

            // Set up the test
            int x          = 5;
            int y          = 10;
            var pointClass = new PointClass(x, y);

            target.DoubleTheTargetPointClass(pointClass);

            // Assert truths.
            Assert.IsNotNull(pointClass);
            Assert.AreEqual(x * 2, pointClass.X);
            Assert.AreEqual(y * 2, pointClass.Y);
        }