Add extra legacy skin parsing tests

osu.Game.Tests/Resources/skin.ini

@@ -1,5 +1,6 @@
 [General]
 Name: test skin
+TestLookup: TestValue
 
 [Colours]
 Combo1 : 142,199,255

osu.Game.Tests/Skins/LegacySkinDecoderTest.cs

@@ -41,5 +41,20 @@ public void TestDecodeSkinColours(bool hasColours)
                     Assert.AreEqual(expectedColors[i], comboColors[i]);
             }
         }
+
+        [Test]
+        public void TestDecodeGeneral()
+        {
+            var decoder = new LegacySkinDecoder();
+
+            using (var resStream = TestResources.OpenResource("skin.ini"))
+            using (var stream = new StreamReader(resStream))
+            {
+                var config = decoder.Decode(stream);
+
+                Assert.AreEqual("test skin", config.SkinInfo.Name);
+                Assert.AreEqual("TestValue", config.ConfigDictionary["TestLookup"]);
+            }
+        }
     }
 }