Added new test-project (with nunit3) and ported the CCombinations tests

Tests/VocaluxeLib/Utils/Combinatorics/CCombinationsTest.cs

@@ -0,0 +1,73 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using NUnit.Framework;
+using VocaluxeLib.Utils.Combinatorics;
+
+namespace Tests.VocaluxeLib.Utils.Combinatorics
+{
+    [TestFixture]
+    public class CCombinationsTest
+    {
+        [Test]
+        public void TestCount()
+        {
+            Assert.AreEqual(4, CCombinations<int>.Count(4, 3));
+            Assert.AreEqual(6, CCombinations<int>.Count(4, 2));
+            Assert.AreEqual(66, CCombinations<int>.Count(12, 2));
+            // Corner cases
+            for (int i = 1; i < 12; i++)
+            {
+                Assert.AreEqual(1, CCombinations<int>.Count(i, 0));
+                Assert.AreEqual(1, CCombinations<int>.Count(i, i));
+                Assert.AreEqual(0, CCombinations<int>.Count(i, i + 1));
+            }
+            // Check identity (n k) = (n n-k)
+            for (int i = 0; i <= 12; i++)
+                Assert.AreEqual(CCombinations<int>.Count(12, i), CCombinations<int>.Count(12, 12 - i));
+            Assert.That(() => CCombinations<int>.Count(-1, -1), Throws.TypeOf<ArgumentException>());
+            Assert.That(() => CCombinations<int>.Count(-1, 1), Throws.TypeOf<ArgumentException>());
+            Assert.That(() => CCombinations<int>.Count(1, -1), Throws.TypeOf<ArgumentException>());
+        }
+
+        [Test]
+        public void TestResults([Range(0, 8, 1)] int n)
+        {
+            Random rand = new Random();
+            
+            for (int k = 0; k <= n; k++)
+            {
+                List<int> collection = new List<int>(n);
+                int r = rand.Next(1000);
+                for (int i = 0; i < n; i++)
+                    collection.Add(i + r);
+                CCombinations<int> combs = new CCombinations<int>(collection, k);
+                Assert.AreEqual(CCombinations<int>.Count(n, k), combs.Count());
+                _CheckResults(combs, collection);
+            }
+        }
+
+        // ReSharper disable UnusedParameter.Local
+        private static void _CheckResults<T>(CCombinations<T> combs, List<T> input)
+        // ReSharper restore UnusedParameter.Local
+        {
+            List<List<T>> results = new List<List<T>>();
+            foreach (List<T> comb in combs)
+            {
+                foreach (List<T> other in results)
+                    Assert.IsFalse(other.SequenceEqual(comb), "Result must be unique");
+                for (int i = 0; i < comb.Count - 1; i++)
+                {
+                    Assert.IsTrue(comb.IndexOf(comb[i], i + 1) < 0, "Repetition not allowed");
+                    Assert.IsTrue(input.Contains(comb[i]), "Output must be in input sequence");
+                }
+                results.Add(comb);
+            }
+            Assert.AreEqual(combs.Count(), results.Count);
+            List<List<T>> results2 = combs.GetAll();
+            Assert.AreEqual(results.Count, results2.Count);
+            for (int i = 0; i < results2.Count; i++)
+                Assert.IsTrue(results[i].SequenceEqual(results2[i]));
+        }
+    }
+}