Consolidate and move ruleset test projects

osu.Game.Rulesets.Osu.Tests/TestCasePerformancePoints.cs

@@ -0,0 +1,16 @@
+// Copyright (c) 2007-2018 ppy Pty Ltd <contact@ppy.sh>.
+// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
+
+using NUnit.Framework;
+
+namespace osu.Game.Rulesets.Osu.Tests
+{
+    [TestFixture]
+    public class TestCasePerformancePoints : Game.Tests.Visual.TestCasePerformancePoints
+    {
+        public TestCasePerformancePoints()
+            : base(new OsuRuleset())
+        {
+        }
+    }
+}