Add filter control test scene

osu.Game.Tests/Visual/SongSelect/TestSceneFilterControl.cs

@@ -0,0 +1,22 @@
+// 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.Screens.Select;
+
+namespace osu.Game.Tests.Visual.SongSelect
+{
+    public class TestSceneFilterControl : OsuTestScene
+    {
+        public TestSceneFilterControl()
+        {
+            Child = new FilterControl
+            {
+                Anchor = Anchor.Centre,
+                Origin = Anchor.Centre,
+                RelativeSizeAxes = Axes.X,
+                Height = FilterControl.HEIGHT,
+            };
+        }
+    }
+}