Add class for calculating combinations and a unitTest

VocaluxeTests/CTestHelpers.cs

@@ -0,0 +1,21 @@
+using System;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+
+namespace VocaluxeTests
+{
+    static class CTestHelpers
+    {
+        public static void AssertFail<T>(Action test) where T : Exception
+        {
+            try
+            {
+                test.Invoke();
+                Assert.Fail("Exception " + typeof(T).Name + " not thrown!");
+            }
+            catch (Exception e)
+            {
+                Assert.IsInstanceOfType(e, typeof(T));
+            }
+        }
+    }
+}

VocaluxeTests/CombinatoricsTest.cs

@@ -0,0 +1,75 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+using VocaluxeLib.Utils.Combinatorics;
+
+namespace VocaluxeTests
+{
+    [TestClass]
+    public class CCombinatoricsTest
+    {
+        [TestMethod]
+        public void TestCounts()
+        {
+            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));
+            CTestHelpers.AssertFail<ArgumentException>(() => CCombinations<int>.Count(-1, -1));
+            CTestHelpers.AssertFail<ArgumentException>(() => CCombinations<int>.Count(-1, 1));
+            CTestHelpers.AssertFail<ArgumentException>(() => CCombinations<int>.Count(1, -1));
+        }
+
+        // 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]));
+        }
+
+        [TestMethod]
+        public void TestResults()
+        {
+            Random rand = new Random();
+            for (int n = 0; n < 8; n++)
+            {
+                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);
+                }
+            }
+        }
+    }
+}

VocaluxeTests/VocaluxeTests.csproj

@@ -70,7 +70,9 @@
     </Otherwise>
   </Choose>
   <ItemGroup>
+    <Compile Include="CTestHelpers.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
+    <Compile Include="CombinatoricsTest.cs" />
     <Compile Include="XmlSerializerTest.cs" />
   </ItemGroup>
   <ItemGroup>

VocaluxeTests/XmlSerializerTest.cs

@@ -91,8 +91,7 @@ namespace VocaluxeTests
 
         private struct SDefaultSub
         {
-            [DefaultValue(111)]
-            public int I;            
+            [DefaultValue(111)] public int I;
         }
 
         private struct SDefault
@@ -107,23 +106,10 @@ namespace VocaluxeTests
 #pragma warning restore 169
 #pragma warning restore 649
 
-        private static void _AssertFail<T>(Action test) where T : Exception
-        {
-            try
-            {
-                test.Invoke();
-                Assert.Fail("Exception " + typeof(T).Name + " not thrown!");
-            }
-            catch (Exception e)
-            {
-                Assert.IsInstanceOfType(e, typeof(T));
-            }
-        }
-
         private static void _AssertFail<T, T2>(String xmlString) where T2 : Exception where T : new()
         {
             var deserializer = new CXmlDeserializer();
-            _AssertFail<T2>(() => deserializer.DeserializeString<T>(xmlString));
+            CTestHelpers.AssertFail<T2>(() => deserializer.DeserializeString<T>(xmlString));
         }
 
         private static T _AssertSerDeserMatch<T>(string xmlString) where T : new()
@@ -454,7 +440,7 @@ namespace VocaluxeTests
             Assert.AreEqual(foo.D, 666);
             Assert.AreEqual(foo.Sub.I, 111);
             string newXml = new CXmlSerializer().Serialize(foo);
-            Assert.AreEqual(_Head +@"<root>
+            Assert.AreEqual(_Head + @"<root>
   <Sub />
 </root>", newXml);
         }