Rewrite difficulty mod combinations

osu.Game.Tests/NonVisual/DifficultyAdjustmentModCombinationsTest.cs

@@ -0,0 +1,152 @@
+// Copyright (c) 2007-2018 ppy Pty Ltd <contact@ppy.sh>.
+// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
+
+using System;
+using System.Collections.Generic;
+using NUnit.Framework;
+using osu.Game.Rulesets.Difficulty;
+using osu.Game.Rulesets.Mods;
+
+namespace osu.Game.Tests.NonVisual
+{
+    [TestFixture]
+    public class DifficultyAdjustmentModCombinationsTest
+    {
+        [Test]
+        public void TestNoMods()
+        {
+            var combinations = new TestDifficultyCalculator().CreateDifficultyAdjustmentModCombinations();
+
+            Assert.AreEqual(1, combinations.Length);
+            Assert.IsTrue(combinations[0] is NoModMod);
+        }
+
+        [Test]
+        public void TestSingleMod()
+        {
+            var combinations = new TestDifficultyCalculator(new ModA()).CreateDifficultyAdjustmentModCombinations();
+
+            Assert.AreEqual(2, combinations.Length);
+            Assert.IsTrue(combinations[0] is NoModMod);
+            Assert.IsTrue(combinations[1] is ModA);
+        }
+
+        [Test]
+        public void TestDoubleMod()
+        {
+            var combinations = new TestDifficultyCalculator(new ModA(), new ModB()).CreateDifficultyAdjustmentModCombinations();
+
+            Assert.AreEqual(4, combinations.Length);
+            Assert.IsTrue(combinations[0] is NoModMod);
+            Assert.IsTrue(combinations[1] is ModA);
+            Assert.IsTrue(combinations[2] is MultiMod);
+            Assert.IsTrue(combinations[3] is ModB);
+
+            Assert.IsTrue(((MultiMod)combinations[2]).Mods[0] is ModA);
+            Assert.IsTrue(((MultiMod)combinations[2]).Mods[1] is ModB);
+        }
+
+        [Test]
+        public void TestIncompatibleMods()
+        {
+            var combinations = new TestDifficultyCalculator(new ModA(), new ModIncompatibleWithA()).CreateDifficultyAdjustmentModCombinations();
+
+            Assert.AreEqual(3, combinations.Length);
+            Assert.IsTrue(combinations[0] is NoModMod);
+            Assert.IsTrue(combinations[1] is ModA);
+            Assert.IsTrue(combinations[2] is ModIncompatibleWithA);
+        }
+
+        [Test]
+        public void TestDoubleIncompatibleMods()
+        {
+            var combinations = new TestDifficultyCalculator(new ModA(), new ModB(), new ModIncompatibleWithA(), new ModIncompatibleWithAAndB()).CreateDifficultyAdjustmentModCombinations();
+
+            Assert.AreEqual(8, combinations.Length);
+            Assert.IsTrue(combinations[0] is NoModMod);
+            Assert.IsTrue(combinations[1] is ModA);
+            Assert.IsTrue(combinations[2] is MultiMod);
+            Assert.IsTrue(combinations[3] is ModB);
+            Assert.IsTrue(combinations[4] is MultiMod);
+            Assert.IsTrue(combinations[5] is ModIncompatibleWithA);
+            Assert.IsTrue(combinations[6] is MultiMod);
+            Assert.IsTrue(combinations[7] is ModIncompatibleWithAAndB);
+
+            Assert.IsTrue(((MultiMod)combinations[2]).Mods[0] is ModA);
+            Assert.IsTrue(((MultiMod)combinations[2]).Mods[1] is ModB);
+            Assert.IsTrue(((MultiMod)combinations[4]).Mods[0] is ModB);
+            Assert.IsTrue(((MultiMod)combinations[4]).Mods[1] is ModIncompatibleWithA);
+            Assert.IsTrue(((MultiMod)combinations[6]).Mods[0] is ModIncompatibleWithA);
+            Assert.IsTrue(((MultiMod)combinations[6]).Mods[1] is ModIncompatibleWithAAndB);
+        }
+
+        [Test]
+        public void TestIncompatibleThroughBaseType()
+        {
+            var combinations = new TestDifficultyCalculator(new ModAofA(), new ModIncompatibleWithAofA()).CreateDifficultyAdjustmentModCombinations();
+
+            Assert.AreEqual(3, combinations.Length);
+            Assert.IsTrue(combinations[0] is NoModMod);
+            Assert.IsTrue(combinations[1] is ModAofA);
+            Assert.IsTrue(combinations[2] is ModIncompatibleWithAofA);
+        }
+
+        private class ModA : Mod
+        {
+            public override string Name => nameof(ModA);
+            public override string ShortenedName => nameof(ModA);
+            public override double ScoreMultiplier => 1;
+
+            public override Type[] IncompatibleMods => new[] { typeof(ModIncompatibleWithA), typeof(ModIncompatibleWithAAndB) };
+        }
+
+        private class ModB : Mod
+        {
+            public override string Name => nameof(ModB);
+            public override string ShortenedName => nameof(ModB);
+            public override double ScoreMultiplier => 1;
+
+            public override Type[] IncompatibleMods => new[] { typeof(ModIncompatibleWithAAndB) };
+        }
+
+        private class ModIncompatibleWithA : Mod
+        {
+            public override string Name => $"Incompatible With {nameof(ModA)}";
+            public override string ShortenedName => $"Incompatible With {nameof(ModA)}";
+            public override double ScoreMultiplier => 1;
+
+            public override Type[] IncompatibleMods => new[] { typeof(ModA) };
+        }
+
+        private class ModAofA : ModA
+        {
+        }
+
+        private class ModIncompatibleWithAofA : ModIncompatibleWithA
+        {
+            // Incompatible through base type
+        }
+
+        private class ModIncompatibleWithAAndB : Mod
+        {
+            public override string Name => $"Incompatible With {nameof(ModA)} and {nameof(ModB)}";
+            public override string ShortenedName => $"Incompatible With {nameof(ModA)} and {nameof(ModB)}";
+            public override double ScoreMultiplier => 1;
+
+            public override Type[] IncompatibleMods => new[] { typeof(ModA), typeof(ModB) };
+        }
+
+        private class TestDifficultyCalculator : DifficultyCalculator
+        {
+            public TestDifficultyCalculator(params Mod[] mods)
+                : base(null)
+            {
+                DifficultyAdjustmentMods = mods;
+            }
+
+            public override double Calculate(Dictionary<string, double> categoryDifficulty = null) => throw new NotImplementedException();
+
+            protected override Mod[] DifficultyAdjustmentMods { get; }
+        }
+    }
+}