Add missing file

osu.Game.Tests/Visual/UserInterface/OsuGridTestScene.cs

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+// 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 osu.Framework.Extensions;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+
+namespace osu.Game.Tests.Visual.UserInterface
+{
+    /// <summary>
+    /// An abstract test case which exposes small cells arranged in a grid.
+    /// Useful for displaying multiple configurations of a tested component at a glance.
+    /// </summary>
+    public abstract class OsuGridTestScene : OsuTestScene
+    {
+        private readonly Drawable[,] cells;
+
+        /// <summary>
+        /// The amount of rows in the grid.
+        /// </summary>
+        protected readonly int Rows;
+
+        /// <summary>
+        /// The amount of columns in the grid.
+        /// </summary>
+        protected readonly int Cols;
+
+        /// <summary>
+        /// Constructs a grid test case with the given dimensions.
+        /// </summary>
+        protected OsuGridTestScene(int rows, int cols)
+        {
+            Rows = rows;
+            Cols = cols;
+
+            GridContainer testContainer;
+            Add(testContainer = new GridContainer { RelativeSizeAxes = Axes.Both });
+
+            cells = new Drawable[rows, cols];
+            for (int r = 0; r < rows; r++)
+            for (int c = 0; c < cols; c++)
+                cells[r, c] = new Container { RelativeSizeAxes = Axes.Both };
+
+            testContainer.Content = cells.ToJagged();
+        }
+
+        protected Container Cell(int index) => (Container)cells[index / Cols, index % Cols];
+        protected Container Cell(int row, int col) => (Container)cells[row, col];
+    }
+}