Add failing test case

osu.Game.Tests/Mods/SettingsSourceAttributeTest.cs

@@ -0,0 +1,36 @@
+// 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 System.Linq;
+using NUnit.Framework;
+using osu.Framework.Bindables;
+using osu.Game.Configuration;
+
+namespace osu.Game.Tests.Mods
+{
+    [TestFixture]
+    public class SettingsSourceAttributeTest
+    {
+        [Test]
+        public void TestOrdering()
+        {
+            var objectWithSettings = new ClassWithSettings();
+
+            var orderedSettings = objectWithSettings.GetOrderedSettingsSourceProperties().ToArray();
+
+            Assert.That(orderedSettings, Has.Length.EqualTo(3));
+        }
+
+        private class ClassWithSettings
+        {
+            [SettingSource("Second setting", "Another description", 2)]
+            public BindableBool SecondSetting { get; set; } = new BindableBool();
+
+            [SettingSource("First setting", "A description", 1)]
+            public BindableDouble FirstSetting { get; set; } = new BindableDouble();
+
+            [SettingSource("Third setting", "Yet another description", 3)]
+            public BindableInt ThirdSetting { get; set; } = new BindableInt();
+        }
+    }
+}