Add test cases for new randomizer behaviour

osu.Game.Tests/Visual/TestCaseBeatmapCarousel.cs

@@ -128,6 +128,20 @@ namespace osu.Game.Tests.Visual
             selectedSets.Pop();
         });
 
+        private bool selectedBeatmapVisible()
+        {
+            var currentlySelected = carousel.Items.FirstOrDefault(s => s.Item is CarouselBeatmap && s.Item.State == CarouselItemState.Selected);
+            if (currentlySelected == null)
+                return true;
+            return !currentlySelected.Item.Filtered;
+        }
+
+        private void checkInvisibleDifficultiesUnselectable()
+        {
+            nextRandom();
+            AddAssert("Selection is visible", selectedBeatmapVisible);
+        }
+
         /// <summary>
         /// Test keyboard traversal
         /// </summary>
@@ -222,6 +236,15 @@ namespace osu.Game.Tests.Visual
 
             nextRandom();
             AddAssert("ensure repeat", () => selectedSets.Contains(carousel.SelectedBeatmapSet));
+
+            AddStep("Add set with 100 difficulties", () => carousel.UpdateBeatmapSet(createTestBeatmapSetWith100Difficulties(set_count + 1)));
+            AddStep("Filter Extra", () => carousel.Filter(new FilterCriteria { SearchText = "Extra 10" }, false));
+            checkInvisibleDifficultiesUnselectable();
+            checkInvisibleDifficultiesUnselectable();
+            checkInvisibleDifficultiesUnselectable();
+            checkInvisibleDifficultiesUnselectable();
+            checkInvisibleDifficultiesUnselectable();
+            AddStep("Un-filter", () => carousel.Filter(new FilterCriteria(), false));
         }
 
         /// <summary>
@@ -384,6 +407,40 @@ namespace osu.Game.Tests.Visual
             };
         }
 
+        private BeatmapSetInfo createTestBeatmapSetWith100Difficulties(int i)
+        {
+            var toReturn = new BeatmapSetInfo
+            {
+                ID = i,
+                OnlineBeatmapSetID = i,
+                Hash = new MemoryStream(Encoding.UTF8.GetBytes(Guid.NewGuid().ToString())).ComputeMD5Hash(),
+                Metadata = new BeatmapMetadata
+                {
+                    OnlineBeatmapSetID = i,
+                    // Create random metadata, then we can check if sorting works based on these
+                    Artist = $"peppy{i.ToString().PadLeft(6, '0')}",
+                    Title = $"test set #{i}!",
+                    AuthorString = string.Concat(Enumerable.Repeat((char)('z' - Math.Min(25, i - 1)), 5))
+                },
+                Beatmaps = new List<BeatmapInfo>(),
+            };
+            for (int b = 1; b < 101; b++)
+            {
+                toReturn.Beatmaps.Add(new BeatmapInfo
+                {
+                    OnlineBeatmapID = b * 10,
+                    Path = $"extra{b}.osu",
+                    Version = $"Extra {b}",
+                    StarDifficulty = 2,
+                    BaseDifficulty = new BeatmapDifficulty
+                    {
+                        OverallDifficulty = 3.5f,
+                    }
+                });
+            }
+            return toReturn;
+        }
+
         private class TestBeatmapCarousel : BeatmapCarousel
         {
             public new List<DrawableCarouselItem> Items => base.Items;