Add zero-length slider test

osu.Game.Rulesets.Mania.Tests/ManiaBeatmapConversionTest.cs

@@ -19,6 +19,7 @@ namespace osu.Game.Rulesets.Mania.Tests
         protected override string ResourceAssembly => "osu.Game.Rulesets.Mania";
 
         [TestCase("basic")]
+        [TestCase("zero-length-slider")]
         public void Test(string name) => base.Test(name);
 
         protected override IEnumerable<ConvertValue> CreateConvertValue(HitObject hitObject)

osu.Game.Rulesets.Mania/Resources/Testing/Beatmaps/zero-length-slider-expected-conversion.json

@@ -0,0 +1,14 @@
+{
+    "Mappings": [{
+        "RandomW": 3083084786,
+        "RandomX": 273326509,
+        "RandomY": 273553282,
+        "RandomZ": 2659838971,
+        "StartTime": 4836,
+        "Objects": [{
+            "StartTime": 4836,
+            "EndTime": 4836,
+            "Column": 0
+        }]
+    }]
+}

osu.Game.Rulesets.Mania/Resources/Testing/Beatmaps/zero-length-slider.osu

@@ -0,0 +1,20 @@
+osu file format v14
+
+[General]
+StackLeniency: 0.7
+Mode: 0
+
+[Difficulty]
+HPDrainRate:1
+CircleSize:4
+OverallDifficulty:1
+ApproachRate:9
+SliderMultiplier:2.5
+SliderTickRate:0.5
+
+[TimingPoints]
+34,431.654676258993,4,1,0,50,1,0
+4782,-66.6666666666667,4,1,0,20,0,0
+
+[HitObjects]
+15,199,4836,22,0,L,1,46.8750017881394