Add basic skin tests

Should be expanded in the future. Bare minimum for now to test fail case.

osu.Game.Tests/Visual/TestCaseSkinReloadable.cs

@@ -0,0 +1,151 @@
+using System;
+using NUnit.Framework;
+using osu.Framework.Audio.Sample;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+using osu.Framework.Graphics.Shapes;
+using osu.Framework.Graphics.Sprites;
+using osu.Framework.Graphics.Textures;
+using osu.Game.Graphics;
+using osu.Game.Skinning;
+using osuTK.Graphics;
+
+namespace osu.Game.Tests.Visual
+{
+    public class TestCaseSkinReloadable : OsuTestCase
+    {
+
+        [Test]
+        public void TestInitialLoad()
+        {
+            var secondarySource = new SecondarySource();
+            SkinConsumer consumer = null;
+
+            AddStep("setup layout", () =>
+            {
+                Child = new SkinSourceContainer
+                {
+                    RelativeSizeAxes = Axes.Both,
+                    Child = new LocalSkinOverrideContainer(secondarySource)
+                    {
+                        RelativeSizeAxes = Axes.Both,
+                        Child = consumer = new SkinConsumer("test", name => new NamedBox("Default Implementation"), source => true)
+                    }
+                };
+            });
+
+            AddAssert("consumer using override source", () => consumer.Drawable is SecondarySourceBox);
+            AddAssert("skinchanged only called once", () => consumer.SkinChangedCount == 1);
+        }
+
+        [Test]
+        public void TestOverride()
+        {
+            var secondarySource = new SecondarySource();
+
+            SkinConsumer consumer = null;
+            Container target = null;
+
+            AddStep("setup layout", () =>
+            {
+                Child = new SkinSourceContainer
+                {
+                    RelativeSizeAxes = Axes.Both,
+                    Child = target = new LocalSkinOverrideContainer(secondarySource)
+                    {
+                        RelativeSizeAxes = Axes.Both,
+                    }
+                };
+            });
+
+            AddStep("add permissive", () => target.Add(consumer = new SkinConsumer("test", name => new NamedBox("Default Implementation"), source => true)));
+            AddAssert("consumer using override source", () => consumer.Drawable is SecondarySourceBox);
+            AddAssert("skinchanged only called once", () => consumer.SkinChangedCount == 1);
+        }
+
+        private class NamedBox : Container
+        {
+            public NamedBox(string name)
+            {
+                Children = new Drawable[]
+                {
+                    new Box
+                    {
+                        Colour = Color4.Black,
+                        RelativeSizeAxes = Axes.Both,
+                    },
+                    new SpriteText
+                    {
+                        Font = OsuFont.Default.With(size: 40),
+                        Anchor = Anchor.Centre,
+                        Origin = Anchor.Centre,
+                        Text = name
+                    }
+                };
+            }
+        }
+
+        private class SkinConsumer : SkinnableDrawable
+        {
+            public new Drawable Drawable => base.Drawable;
+            public int SkinChangedCount { get; private set; }
+
+            public SkinConsumer(string name, Func<string, Drawable> defaultImplementation, Func<ISkinSource, bool> allowFallback = null, bool restrictSize = true)
+                : base(name, defaultImplementation, allowFallback, restrictSize)
+            {
+            }
+
+            protected override void SkinChanged(ISkinSource skin, bool allowFallback)
+            {
+                base.SkinChanged(skin, allowFallback);
+                SkinChangedCount++;
+            }
+        }
+
+        private class BaseSourceBox : NamedBox
+        {
+            public BaseSourceBox()
+                : base("Base Source")
+            {
+            }
+        }
+
+        private class SecondarySourceBox : NamedBox
+        {
+            public SecondarySourceBox()
+                : base("Secondary Source")
+            {
+            }
+        }
+
+        private class SecondarySource : ISkinSource
+        {
+            public event Action SourceChanged;
+
+            public void TriggerSourceChanged() => SourceChanged?.Invoke();
+
+            public Drawable GetDrawableComponent(string componentName) => new SecondarySourceBox();
+
+            public Texture GetTexture(string componentName) => throw new NotImplementedException();
+
+            public SampleChannel GetSample(string sampleName) => throw new NotImplementedException();
+
+            public TValue GetValue<TConfiguration, TValue>(Func<TConfiguration, TValue> query) where TConfiguration : SkinConfiguration => throw new NotImplementedException();
+        }
+
+        private class SkinSourceContainer : Container, ISkinSource
+        {
+            public event Action SourceChanged;
+
+            public void TriggerSourceChanged() => SourceChanged?.Invoke();
+
+            public Drawable GetDrawableComponent(string componentName) => new BaseSourceBox();
+
+            public Texture GetTexture(string componentName) => throw new NotImplementedException();
+
+            public SampleChannel GetSample(string sampleName) => throw new NotImplementedException();
+
+            public TValue GetValue<TConfiguration, TValue>(Func<TConfiguration, TValue> query) where TConfiguration : SkinConfiguration => throw new NotImplementedException();
+        }
+    }
+}