public void TestTurnMove()
        {
            Turtle t = new Turtle();
            t.Left(45);
            t.Forward(10);

            Assert.AreEqual(7.07, t.X, 0.002);
            Assert.AreEqual(7.07, t.Y, 0.002);

            t.Undo();
            t.Left(45);
            t.Forward(10);

            Assert.AreEqual(0, t.X, 0.002);
            Assert.AreEqual(10, t.Y);

            t.Undo();
            t.Left(45);
            t.Forward(10);

            Assert.AreEqual(-7.07, t.X, 0.002);
            Assert.AreEqual(7.07, t.Y, 0.002);
        }