Add failing test cases

osu.Game.Tests/NonVisual/GameplayClockTest.cs

@@ -0,0 +1,39 @@
+// 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.Collections.Generic;
+using NUnit.Framework;
+using osu.Framework.Bindables;
+using osu.Framework.Timing;
+using osu.Game.Screens.Play;
+
+namespace osu.Game.Tests.NonVisual
+{
+    [TestFixture]
+    public class GameplayClockTest
+    {
+        [TestCase(0)]
+        [TestCase(1)]
+        public void TestTrueGameplayRateWithZeroAdjustment(double underlyingClockRate)
+        {
+            var framedClock = new FramedClock(new ManualClock { Rate = underlyingClockRate });
+            var gameplayClock = new TestGameplayClock(framedClock);
+
+            gameplayClock.MutableNonGameplayAdjustments.Add(new BindableDouble());
+
+            Assert.That(gameplayClock.TrueGameplayRate, Is.EqualTo(0));
+        }
+
+        private class TestGameplayClock : GameplayClock
+        {
+            public List<Bindable<double>> MutableNonGameplayAdjustments { get; } = new List<Bindable<double>>();
+
+            public override IEnumerable<Bindable<double>> NonGameplayAdjustments => MutableNonGameplayAdjustments;
+
+            public TestGameplayClock(IFrameBasedClock underlyingClock)
+                : base(underlyingClock)
+            {
+            }
+        }
+    }
+}