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); }