Add helper method for editor check tests

osu.Game.Tests/Editing/Checks/CheckTestHelpers.cs

@@ -0,0 +1,18 @@
+// 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.Game.Beatmaps;
+using osu.Game.IO;
+
+namespace osu.Game.Tests.Editing.Checks
+{
+    public static class CheckTestHelpers
+    {
+        public static BeatmapSetFileInfo CreateMockFile(string extension) =>
+            new BeatmapSetFileInfo
+            {
+                Filename = $"abc123.{extension}",
+                FileInfo = new FileInfo { Hash = "abcdef" }
+            };
+    }
+}