Fix multiple categories serialization problem #156

v2/ical.NET.UnitTests/SymmetricSerializationTests.cs

@@ -3,6 +3,7 @@
 using System.IO;
 using System.Linq;
 using System.Text;
+using System.Text.RegularExpressions;
 using Ical.Net.DataTypes;
 using Ical.Net.Interfaces;
 using Ical.Net.Interfaces.DataTypes;
@@ -200,5 +201,18 @@ public static IEnumerable<ITestCaseData> UriAttachment_TestCases()
             yield return new TestCaseData("C:\\path\\to\\file.txt", new Uri("C:\\path\\to\\file.txt")).SetName("Local file path URL");
             yield return new TestCaseData("\\\\uncPath\\to\\resource.txt", new Uri("\\\\uncPath\\to\\resource.txt")).SetName("UNC path URL");
         }
+
+        [Test]
+        public void CategoriesTest()
+        {
+            var vEvent = GetSimpleEvent();
+            vEvent.Categories = new List<string> {"Foo", "Bar", "Baz"};
+            var c = new Calendar();
+            c.Events.Add(vEvent);
+
+            var serialized = SerializeToString(c);
+            var categoriesCount = Regex.Matches(serialized, "CATEGORIES").Count;
+            Assert.AreEqual(1, categoriesCount);
+        }
     }
 }