Add visual test case for report button

Makes it much easier to test button/popover design changes

osu.Game.Tests/Visual/Online/TestSceneCommentReportButton.cs

@@ -0,0 +1,46 @@
+// 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.Cursor;
+using osu.Framework.Testing;
+using osu.Game.Online.API;
+using osu.Game.Online.API.Requests;
+using osu.Game.Online.API.Requests.Responses;
+using osu.Game.Overlays.Comments;
+using osu.Game.Tests.Visual.UserInterface;
+using osuTK;
+
+namespace osu.Game.Tests.Visual.Online
+{
+    public class TestSceneCommentReportButton : ThemeComparisonTestScene
+    {
+        [SetUpSteps]
+        public void SetUpSteps()
+        {
+            AddStep("setup API", () => ((DummyAPIAccess)API).HandleRequest += req =>
+            {
+                switch (req)
+                {
+                    case CommentReportRequest report:
+                        Scheduler.AddDelayed(report.TriggerSuccess, 1000);
+                        return true;
+                }
+
+                return false;
+            });
+        }
+
+        protected override Drawable CreateContent() => new PopoverContainer
+        {
+            RelativeSizeAxes = Axes.Both,
+            Child = new CommentReportButton(new Comment { User = new APIUser { Username = "Someone" } })
+            {
+                Anchor = Anchor.Centre,
+                Origin = Anchor.Centre,
+                Scale = new Vector2(2f),
+            }.With(b => Schedule(b.ShowPopover)),
+        };
+    }
+}