public void TestMidOrderNormal2()
        {
            var root   = TreeGenerator.GetSimpleNormalTree();
            var result = new List <string>();

            TreeWalk.MidOrderNormal2(root, result);
            var actual   = string.Join(" ", result);
            var expected = "D B E A F C G";

            Assert.AreEqual(expected, actual);

            root   = TreeGenerator.GetSimpleTree();
            result = new List <string>();
            TreeWalk.MidOrderNormal2(root, result);
            actual   = string.Join(" ", result);
            expected = "D B A G E C F";
            Assert.AreEqual(expected, actual);
        }