Move all TestCases to Testing project

This allows tests to successfully retrieve rulesets, as they are referenced.

osu.Game.Tests/Visual/TestCaseOnScreenDisplay.cs

@@ -0,0 +1,46 @@
+// Copyright (c) 2007-2017 ppy Pty Ltd <contact@ppy.sh>.
+// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
+
+using osu.Framework.Allocation;
+using osu.Framework.Configuration;
+using osu.Game.Overlays;
+
+namespace osu.Game.Tests.Visual
+{
+    internal class TestCaseOnScreenDisplay : OsuTestCase
+    {
+        private FrameworkConfigManager config;
+        private Bindable<FrameSync> frameSyncMode;
+
+        public override string Description => @"Make it easier to see setting changes";
+
+        protected override void LoadComplete()
+        {
+            base.LoadComplete();
+
+            Add(new OnScreenDisplay());
+
+            frameSyncMode = config.GetBindable<FrameSync>(FrameworkSetting.FrameSync);
+
+            FrameSync initial = frameSyncMode.Value;
+
+            AddRepeatStep(@"Change frame limiter", setNextMode, 3);
+
+            AddStep(@"Restore frame limiter", () => frameSyncMode.Value = initial);
+        }
+
+        private void setNextMode()
+        {
+            var nextMode = frameSyncMode.Value + 1;
+            if (nextMode > FrameSync.Unlimited)
+                nextMode = FrameSync.VSync;
+            frameSyncMode.Value = nextMode;
+        }
+
+        [BackgroundDependencyLoader]
+        private void load(FrameworkConfigManager config)
+        {
+            this.config = config;
+        }
+    }
+}