Add test coverage

osu.Game.Rulesets.Osu.Tests/Mods/TestSceneOsuModMuted.cs

@@ -0,0 +1,28 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using System.Linq;
+using NUnit.Framework;
+using osu.Framework.Testing;
+using osu.Game.Rulesets.Mods;
+using osu.Game.Rulesets.Osu.Mods;
+
+namespace osu.Game.Rulesets.Osu.Tests.Mods
+{
+    public class TestSceneOsuModMuted : OsuModTestScene
+    {
+        /// <summary>
+        /// Ensures that a final volume combo of 0 (i.e. "always muted" mode) constantly plays metronome and completely mutes track.
+        /// </summary>
+        [TestCase(0.0, 1.0)]
+        public void TestZeroFinalCombo(double expectedTrackVolume, double expectedMetronomeVolume) => CreateModTest(new ModTestData
+        {
+            Mod = new OsuModMuted
+            {
+                MuteComboCount = { Value = 0 },
+            },
+            PassCondition = () => Beatmap.Value.Track.AggregateVolume.Value == expectedTrackVolume &&
+                                  Player.ChildrenOfType<Metronome>().SingleOrDefault()?.AggregateVolume.Value == expectedMetronomeVolume,
+        });
+    }
+}