Add test scene

osu.Game.Tests/Visual/UserInterface/TestSceneVolumeOverlay.cs

@@ -0,0 +1,32 @@
+// 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 osu.Framework.Graphics;
+using osu.Game.Overlays;
+using osu.Game.Overlays.Volume;
+
+namespace osu.Game.Tests.Visual.UserInterface
+{
+    public class TestSceneVolumeOverlay : OsuTestScene
+    {
+        private VolumeOverlay volume;
+
+        protected override void LoadComplete()
+        {
+            base.LoadComplete();
+
+            AddRange(new Drawable[]
+            {
+                volume = new VolumeOverlay(),
+                new VolumeControlReceptor
+                {
+                    RelativeSizeAxes = Axes.Both,
+                    ActionRequested = action => volume.Adjust(action),
+                    ScrollActionRequested = (action, amount, isPrecise) => volume.Adjust(action, amount, isPrecise),
+                },
+            });
+
+            AddStep("show controls", () => volume.Show());
+        }
+    }
+}