Fix discarding too many RNG values, and add test

osu.Game.Rulesets.Catch.Tests/CatchBeatmapConversionTest.cs

@@ -17,6 +17,7 @@ namespace osu.Game.Rulesets.Catch.Tests
         protected override string ResourceAssembly => "osu.Game.Rulesets.Catch";
 
         [TestCase("basic"), Ignore("See: https://github.com/ppy/osu/issues/2232")]
+        [TestCase("spinner")]
         public new void Test(string name)
         {
             base.Test(name);
@@ -35,6 +36,17 @@ namespace osu.Game.Rulesets.Catch.Tests
                     };
                 }
             }
+            else if (hitObject is BananaShower shower)
+            {
+                foreach (var nested in shower.NestedHitObjects)
+                {
+                    yield return new ConvertValue
+                    {
+                        StartTime = nested.StartTime,
+                        Position = ((CatchHitObject)nested).X * CatchPlayfield.BASE_WIDTH
+                    };
+                }
+            }
             else
             {
                 yield return new ConvertValue

osu.Game.Rulesets.Catch/Beatmaps/CatchBeatmapProcessor.cs

@@ -48,10 +48,8 @@ namespace osu.Game.Rulesets.Catch.Beatmaps
                         foreach (var nested in bananaShower.NestedHitObjects)
                         {
                             ((BananaShower.Banana)nested).X = (float)rng.NextDouble();
-                            // discarding 3 times
+                            rng.Next(); // osu!stable retrieved a random banana type
-                            rng.Next();
+                            rng.Next(); // osu!stable retrieved a random banana rotation
-                            rng.Next();
-                            rng.Next();
                         }
                         break;
                     case JuiceStream juiceStream:

osu.Game.Rulesets.Catch/Resources/Testing/Beatmaps/spinner-expected-conversion.json

@@ -0,0 +1,74 @@
+{
+    "Mappings": [{
+        "StartTime": 18500,
+        "Objects": [{
+                "StartTime": 18500,
+                "Position": 65
+            },
+            {
+                "StartTime": 18559,
+                "Position": 459
+            },
+            {
+                "StartTime": 18618,
+                "Position": 255
+            },
+            {
+                "StartTime": 18678,
+                "Position": 113
+            },
+            {
+                "StartTime": 18737,
+                "Position": 315
+            },
+            {
+                "StartTime": 18796,
+                "Position": 17
+            },
+            {
+                "StartTime": 18856,
+                "Position": 482
+            },
+            {
+                "StartTime": 18915,
+                "Position": 44
+            },
+            {
+                "StartTime": 18975,
+                "Position": 310
+            },
+            {
+                "StartTime": 19034,
+                "Position": 244
+            },
+            {
+                "StartTime": 19093,
+                "Position": 18
+            },
+            {
+                "StartTime": 19153,
+                "Position": 482
+            },
+            {
+                "StartTime": 19212,
+                "Position": 243
+            },
+            {
+                "StartTime": 19271,
+                "Position": 332
+            },
+            {
+                "StartTime": 19331,
+                "Position": 477
+            },
+            {
+                "StartTime": 19390,
+                "Position": 376
+            },
+            {
+                "StartTime": 19450,
+                "Position": 104
+            }
+        ]
+    }]
+}

osu.Game.Rulesets.Catch/Resources/Testing/Beatmaps/spinner.osu

@@ -0,0 +1,20 @@
+osu file format v14
+
+[General]
+Mode: 2
+
+[Difficulty]
+HPDrainRate:6
+CircleSize:4
+OverallDifficulty:7
+ApproachRate:8.3
+SliderMultiplier:1.6
+SliderTickRate:1
+
+[TimingPoints]
+500,500,4,2,1,50,1,0
+13426,-100,4,3,1,45,0,0
+14884,-100,4,2,1,50,0,0
+
+[HitObjects]
+256,192,18500,12,0,19450,0:0:0:0: