Add migration test

osu.Game.Tests/Visual/Navigation/OsuGameTestScene.cs

@@ -62,14 +62,7 @@ public void SetUpSteps()
                 var frameworkConfig = host.Dependencies.Get<FrameworkConfigManager>();
                 frameworkConfig.GetBindable<double>(FrameworkSetting.CursorSensitivity).Disabled = false;
 
-                Game = new TestOsuGame(LocalStorage, API);
-                Game.SetHost(host);
-
-                // todo: this can be removed once we can run audio tracks without a device present
-                // see https://github.com/ppy/osu/issues/1302
-                Game.LocalConfig.Set(OsuSetting.IntroSequence, IntroSequence.Circles);
-
-                Add(Game);
+                CreateGame();
             });
 
             AddUntilStep("Wait for load", () => Game.IsLoaded);
@@ -78,6 +71,18 @@ public void SetUpSteps()
             ConfirmAtMainMenu();
         }
 
+        protected void CreateGame()
+        {
+            Game = new TestOsuGame(LocalStorage, API);
+            Game.SetHost(host);
+
+            // todo: this can be removed once we can run audio tracks without a device present
+            // see https://github.com/ppy/osu/issues/1302
+            Game.LocalConfig.Set(OsuSetting.IntroSequence, IntroSequence.Circles);
+
+            Add(Game);
+        }
+
         protected void PushAndConfirm(Func<Screen> newScreen)
         {
             Screen screen = null;
@@ -103,6 +108,8 @@ public class TestOsuGame : OsuGame
 
             public new Bindable<RulesetInfo> Ruleset => base.Ruleset;
 
+            public override string Version => "test game";
+
             protected override Loader CreateLoader() => new TestLoader();
 
             public new void PerformFromScreen(Action<IScreen> action, IEnumerable<Type> validScreens = null) => base.PerformFromScreen(action, validScreens);

osu.Game.Tests/Visual/Navigation/TestSettingsMigration.cs

@@ -0,0 +1,41 @@
+// 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 NUnit.Framework;
+using osu.Framework.Utils;
+using osu.Game.Configuration;
+
+namespace osu.Game.Tests.Visual.Navigation
+{
+    public class TestSettingsMigration : OsuGameTestScene
+    {
+        public override void RecycleLocalStorage()
+        {
+            base.RecycleLocalStorage();
+
+            using (var config = new OsuConfigManager(LocalStorage))
+            {
+                config.Set(OsuSetting.Version, "2020.101.0");
+                config.Set(OsuSetting.DisplayStarsMaximum, 10.0);
+            }
+        }
+
+        [Test]
+        public void TestDisplayStarsMigration()
+        {
+            AddAssert("config has migrated value", () => Precision.AlmostEquals(Game.LocalConfig.Get<double>(OsuSetting.DisplayStarsMaximum), 10.1));
+
+            AddStep("set value again", () => Game.LocalConfig.Set<double>(OsuSetting.DisplayStarsMaximum, 10));
+
+            AddStep("force save config", () => Game.LocalConfig.Save());
+
+            AddStep("remove game", () => Remove(Game));
+
+            AddStep("create game again", CreateGame);
+
+            AddUntilStep("Wait for load", () => Game.IsLoaded);
+
+            AddAssert("config did not migrate value", () => Precision.AlmostEquals(Game.LocalConfig.Get<double>(OsuSetting.DisplayStarsMaximum), 10));
+        }
+    }
+}

osu.Game/OsuGameBase.cs

@@ -97,7 +97,7 @@ public class OsuGameBase : Framework.Game, ICanAcceptFiles
 
         public bool IsDeployedBuild => AssemblyVersion.Major > 0;
 
-        public string Version
+        public virtual string Version
         {
             get
             {

osu.Game/Tests/Visual/OsuTestScene.cs

@@ -104,7 +104,7 @@ protected OsuTestScene()
             base.Content.Add(content = new DrawSizePreservingFillContainer());
         }
 
-        public void RecycleLocalStorage()
+        public virtual void RecycleLocalStorage()
         {
             if (localStorage?.IsValueCreated == true)
             {