Adding MultiMap unit tests.

Assets/Editor/Anvoker.Collections/Maps/MultiMap.meta

+fileFormatVersion: 2
+guid: ee2345ce74b53b94a9dc75c94e4da301
+folderAsset: yes
+DefaultImporter:
+  externalObjects: {}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

Assets/Editor/Anvoker.Collections/Maps/MultiMap/Constructors.cs

+using System;
+using System.Collections;
+using System.Collections.Generic;
+using NUnit.Framework;
+
+namespace Anvoker.Collections.Maps.Tests.MultiMap
+{
+    /// <summary>
+    /// Unit tests for <see cref="MultiMap{TKey, TVal}"/>'s constructors.
+    /// </summary>
+    [TestFixture]
+    public class Constructors
+    {
+        /// <summary>
+        /// Checks that the parameterless constructor leaves the new MultiMap
+        /// in the expected state.
+        /// </summary>
+        [Test]
+        public void ParameterlessConstructor()
+        {
+            var multiMap = new MultiMap<string, int>();
+            Assert.AreEqual(0, multiMap.Count);
+            Assert.AreEqual(0, multiMap.Keys.Count);
+            Assert.AreEqual(0, multiMap.Values.Count);
+            Assert.AreEqual(
+                EqualityComparer<string>.Default, multiMap.ComparerKey);
+            Assert.AreEqual(
+                EqualityComparer<int>.Default, multiMap.ComparerValue);
+        }
+
+        /// <summary>
+        /// Checks that the constructor with the capacity parameter leaves
+        /// the new MultiMap in the expected state.
+        /// </summary>
+        [Test]
+        public void CapacityConstructor()
+        {
+            var multiMap = new MultiMap<string, int>(10);
+            Assert.AreEqual(0, multiMap.Count);
+            Assert.AreEqual(0, multiMap.Keys.Count);
+            Assert.AreEqual(0, multiMap.Values.Count);
+            Assert.AreEqual(
+                EqualityComparer<string>.Default, multiMap.ComparerKey);
+            Assert.AreEqual(
+                EqualityComparer<int>.Default, multiMap.ComparerValue);
+        }
+
+        /// <summary>
+        /// Checks that the constructor with the comparer parameters leaves
+        /// the new MultiMap in the expected state.
+        /// </summary>
+        [Test]
+        public void ComparerConstructor()
+        {
+            var comparerKey = StringComparer.OrdinalIgnoreCase;
+            var comparerValue = StringComparer.InvariantCulture;
+            var multiMap = new MultiMap<string, string>(
+                comparerKey, comparerValue);
+            Assert.AreEqual(0, multiMap.Count);
+            Assert.AreEqual(comparerKey, multiMap.ComparerKey);
+            Assert.AreEqual(comparerValue, multiMap.ComparerValue);
+            Assert.AreEqual(0, multiMap.Keys.Count);
+            Assert.AreEqual(0, multiMap.Values.Count);
+        }
+    }
+}

Assets/Editor/Anvoker.Collections/Maps/MultiMap/Constructors.cs.meta

+fileFormatVersion: 2
+guid: 20c0e5437dc90824bb08e7913fb78467
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

Assets/Editor/Anvoker.Collections/Maps/MultiMap/FixtureSource_IntDecimal.cs

+using System;
+using System.Collections;
+using System.Collections.Generic;
+using NUnit.Framework;
+
+namespace Anvoker.Collections.Maps.Tests.MultiMap
+{
+    /// <summary>
+    /// Provides test data for <see cref="NestedIDictionary_IntDecimal"/>.
+    /// </summary>
+    internal static class FixtureSource_IntDecimal
+    {
+        private static readonly int[] intKeys = new int[]
+        {
+            25, 37, 99, 20, -5
+        };
+
+        private static readonly int[] intKeysExcluded = new int[]
+        {
+            24, 2, -8
+        };
+
+        private static readonly decimal[][] decimalValues = new decimal[][]
+        {
+            new decimal[] { 0.1m },
+            new decimal[] { 5.25m, 0.0m },
+            new decimal[] { 5.25m, 0.0m, 2.0m, 5.0m },
+            new decimal[] { 1.75m },
+            new decimal[] { 3.75m },
+        };
+
+        /// <summary>
+        /// Provides the arguments for a test fixture that is decorated with
+        /// <see cref="TestCaseSourceAttribute"/> and has a constructor with
+        /// matching parameter types.
+        /// </summary>
+        /// <returns>An array of objects where each object is a collection
+        /// that contains all of the necessary parameters to run a constructor
+        /// of matching type.</returns>
+        public static object[] FixtureArgs() => new object[]
+        {
+            ConstructIntDecimalCase()
+        };
+
+        private static object[] ConstructIntDecimalCase()
+        {
+            var multiMap = new MultiMap<int, decimal>()
+            {
+                { intKeys[0], decimalValues[0] },
+                { intKeys[1], decimalValues[1] },
+                { intKeys[2], decimalValues[2] },
+                { intKeys[3], decimalValues[3] },
+                { intKeys[4], decimalValues[4] }
+            };
+
+            return new object[]
+            {
+                multiMap,
+                intKeys,
+                (ICollection<decimal>[])decimalValues,
+                intKeysExcluded
+            };
+        }
+    }
+}
\ No newline at end of file

Assets/Editor/Anvoker.Collections/Maps/MultiMap/FixtureSource_IntDecimal.cs.meta

+fileFormatVersion: 2
+guid: b1ce25a70ec7d754dbf876e89bc0145b
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

Assets/Editor/Anvoker.Collections/Maps/MultiMap/NestedIDictionary.cs

+using System;
+using System.Collections;
+using System.Collections.Generic;
+using NUnit.Framework;
+
+namespace Anvoker.Collections.Maps.Tests.MultiMap.IDictionary
+{
+    /// <summary>
+    /// Does nothing but specify some of the types for
+    /// <see cref="NestedIDictionaryBase{TKey, TVal, TIDict, TValCol}"/>,
+    /// leaving only the key and value types as generic.
+    /// </summary>
+    /// <typeparam name="TKey">Type of the keys in the
+    /// <see cref="MultiMap{TKey, TVal}"/>.</typeparam>
+    /// <typeparam name="TVal">Type of the values in the
+    /// <see cref="MultiMap{TKey, TVal}"/>.</typeparam>
+    public class NestedIDictionary<TKey, TVal>
+        : NestedIDictionaryBase<TKey, TVal, MultiMap<TKey, TVal>,
+            ICollection<TVal>>
+    {
+        /// <summary>
+        /// Initializes a new instance of the
+        /// <see cref="NestedIDictionary{TKey, TVal}"/> class with and the
+        /// specified keys and values.
+        /// </summary>
+        /// <param name="multiMap">An instance of
+        /// <see cref="MultiMap{TKey, TVal}"/> already initialized with the
+        /// specified keys and values.</param>
+        /// <param name="initialKeys">An enumeration of keys also found in the
+        /// specified <paramref name="multiMap"/>.
+        /// <para>Used to verify tests.</para></param>
+        /// <param name="initialValueCollections">An enumeration of collections
+        /// of values also found in <paramref name="multiMap"/>.
+        /// <para>Used to verify tests.</para></param>
+        /// <param name="excludedKeys">An enumeration of value of the same type
+        /// as the keys in <paramref name="multiMap"/>, none of which are
+        /// contained in <paramref name="multiMap"/>.
+        /// <para>Used to test for false positives.</para></param>
+        public NestedIDictionary(
+            MultiMap<TKey, TVal> multiMap,
+            TKey[] initialKeys,
+            ICollection<TVal>[] initialValueCollections,
+            TKey[] excludedKeys)
+            : base(multiMap, initialKeys, initialValueCollections, excludedKeys)
+        {
+        }
+    }
+}
\ No newline at end of file

Assets/Editor/Anvoker.Collections/Maps/MultiMap/NestedIDictionary.cs.meta

+fileFormatVersion: 2
+guid: 4999d849d360bba4292e6aa94995556f
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

Assets/Editor/Anvoker.Collections/Maps/MultiMap/NestedIDictionary_IntDecimal.cs

+using System;
+using System.Collections;
+using System.Collections.Generic;
+using NUnit.Framework;
+using NUnit.Framework.Api;
+
+namespace Anvoker.Collections.Maps.Tests.MultiMap.IDictionary
+{
+    /// <summary>
+    /// Runs tests from
+    /// <see cref="NestedIDictionaryBase{TKey, TVal, TIDict, TValCol}"/>
+    /// on <see cref="MultiMap{TKey, TVal}"/> using test data from
+    /// <see cref="FixtureSource_IntDecimal"/>.
+    /// </summary>
+    [TestFixture, TestFixtureSource(
+        typeof(FixtureSource_IntDecimal),
+        nameof(FixtureSource_IntDecimal.FixtureArgs))]
+    public class IntDecimal : NestedIDictionary<int, decimal>
+    {
+        /// <summary>
+        /// Initializes a new instance of the
+        /// <see cref="IntDecimal"/> class with and the
+        /// specified keys and values of <see cref="int"/> and
+        /// <see cref="decimal"/> type respectively.
+        /// </summary>
+        /// <param name="multiMap">An instance of
+        /// <see cref="MultiMap{TKey, TVal}"/> already initialized with the
+        /// specified keys and values.</param>
+        /// <param name="initialKeys">An enumeration of keys also found in the
+        /// specified <paramref name="multiMap"/>.
+        /// <para>Used to verify tests.</para></param>
+        /// <param name="initialValueCollections">An enumeration of collections
+        /// of values also found in <paramref name="multiMap"/>.
+        /// <para>Used to verify tests.</para></param>
+        /// <param name="excludedKeys">An enumeration of value of the same type
+        /// as the keys in <paramref name="multiMap"/>, none of which are
+        /// contained in <paramref name="multiMap"/>.
+        /// <para>Used to test for false positives.</para></param>
+        public IntDecimal(
+            MultiMap<int, decimal> multiMap,
+            int[] initialKeys,
+            ICollection<decimal>[] initialValueCollections,
+            int[] excludedKeys)
+            : base(multiMap, initialKeys, initialValueCollections, excludedKeys)
+        {
+        }
+    }
+}
\ No newline at end of file

Assets/Editor/Anvoker.Collections/Maps/MultiMap/NestedIDictionary_IntDecimal.cs.meta

+fileFormatVersion: 2
+guid: 688f05cfcf191d14088bf8e5465d3775
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: