Add parsing test

osu.Game.Tests/Beatmaps/Formats/LegacyBeatmapDecoderTest.cs

@@ -186,6 +186,18 @@ public void TestDecodeBeatmapColors()
             }
         }
 
+        [Test]
+        public void TestDecodeBeatmapComboOffsets()
+        {
+            var decoder = new LegacyBeatmapDecoder();
+            using (var resStream = Resource.OpenResource("hitobject-combo-offset.osu"))
+            using (var stream = new StreamReader(resStream))
+            {
+                var beatmap = decoder.Decode(stream);
+                Assert.AreEqual(3, ((IHasCombo)beatmap.HitObjects[0]).ComboOffset);
+            }
+        }
+
         [Test]
         public void TestDecodeBeatmapHitObjects()
         {

osu.Game.Tests/Resources/hitobject-combo-offset.osu

@@ -0,0 +1,4 @@
+osu file format v14
+
+[HitObjects]
+255,193,2170,49,0,0:0:0:0: