Merge pull request #13785 from ekrctb/dependency-providing-container

Add a convenient way to provide ad-hoc dependency to children in visual test

osu.Game/Tests/Visual/DependencyProvidingContainer.cs

@@ -0,0 +1,34 @@
+// 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;
+using osu.Framework.Allocation;
+using osu.Framework.Graphics.Containers;
+
+namespace osu.Game.Tests.Visual
+{
+    /// <summary>
+    /// A <see cref="Container"/> which providing ad-hoc dependencies to the child drawables.
+    /// </summary>
+    /// <remarks>
+    /// The <see cref="CachedDependencies"/> must be set while this <see cref="DependencyProvidingContainer"/> is not loaded.
+    /// </remarks>
+    public class DependencyProvidingContainer : Container
+    {
+        /// <summary>
+        /// The dependencies provided to the children.
+        /// </summary>
+        // TODO: should be an init-only property when C# 9
+        public (Type, object)[] CachedDependencies { get; set; } = Array.Empty<(Type, object)>();
+
+        protected override IReadOnlyDependencyContainer CreateChildDependencies(IReadOnlyDependencyContainer parent)
+        {
+            var dependencyContainer = new DependencyContainer(base.CreateChildDependencies(parent));
+
+            foreach (var (type, value) in CachedDependencies)
+                dependencyContainer.CacheAs(type, value);
+
+            return dependencyContainer;
+        }
+    }
+}