Accord.Tests.Math.RedBlackDictionaryTest.NextPrevTest C# (CSharp) Method

        public void NextPrevTest()
        {
            bool thrown = false; 

            var map = new RedBlackTreeDictionary<int, string>();

            map[0] = "0";
            map[1] = "1";
            map[2] = "2";


            {
                var a = map.GetNext(0);
                Assert.AreEqual(1, a.Key);
                Assert.IsTrue(map.TryGetNext(0, out a));
                Assert.AreEqual(1, a.Key);

                var b = map.GetNext(1);
                Assert.AreEqual(2, b.Key);
                Assert.IsTrue(map.TryGetNext(1, out b));
                Assert.AreEqual(2, b.Key);

                thrown = false;
                try { map.GetNext(2); }
                catch (KeyNotFoundException) { thrown = true; }
                Assert.IsTrue(thrown);
                Assert.IsFalse(map.TryGetNext(2, out b));

                thrown = false;
                try { map.GetNext(-1); }
                catch (KeyNotFoundException) { thrown = true; }
                Assert.IsTrue(thrown);
                Assert.IsFalse(map.TryGetNext(-1, out b));
            }

            {
                KeyValuePair<int, string> a;

                thrown = false;
                try {  a = map.GetPrevious(0); }
                catch (KeyNotFoundException) { thrown = true; }
                Assert.IsTrue(thrown);
                Assert.IsFalse(map.TryGetPrevious(0, out a));
                Assert.AreEqual(0, a.Key);

                var b = map.GetPrevious(1);
                Assert.AreEqual(0, b.Key);
                Assert.IsTrue(map.TryGetPrevious(1, out b));
                Assert.AreEqual(0, b.Key);

                var c = map.GetPrevious(2);
                Assert.AreEqual(1, c.Key);
                Assert.IsTrue(map.TryGetPrevious(2, out b));
                Assert.AreEqual(1, b.Key);

                thrown = false;
                try { map.GetNext(3); }
                catch (KeyNotFoundException) { thrown = true; }
                Assert.IsTrue(thrown);
            }
        }