diff --git a/osu.Game.Tests/Visual/UserInterface/TestSceneModSelectOverlay.cs b/osu.Game.Tests/Visual/UserInterface/TestSceneModSelectOverlay.cs
index b429619044..9083415a78 100644
--- a/osu.Game.Tests/Visual/UserInterface/TestSceneModSelectOverlay.cs
+++ b/osu.Game.Tests/Visual/UserInterface/TestSceneModSelectOverlay.cs
@@ -457,10 +457,12 @@ namespace osu.Game.Tests.Visual.UserInterface
             public override ModType Type => ModType.Conversion;
         }
 
-        private class TestUnimplementedModOsuRuleset : OsuRuleset
+        private class TestUnimplementedModOsuRuleset : OsuRuleset, ILegacyRuleset
         {
             public override string ShortName => "unimplemented";
 
+            int ILegacyRuleset.LegacyID => -1;
+
             public override IEnumerable<Mod> GetModsFor(ModType type)
             {
                 if (type == ModType.Conversion) return base.GetModsFor(type).Concat(new[] { new TestUnimplementedMod() });