public void SerializeNullableDateTimeClass()
    {
      NullableDateTimeTestClass t = new NullableDateTimeTestClass()
      {
        DateTimeField = null,
        DateTimeOffsetField = null
      };

      JavaScriptDateTimeConverter converter = new JavaScriptDateTimeConverter();

      string result;

      result = JsonConvert.SerializeObject(t, converter);
      Assert.AreEqual(@"{""PreField"":null,""DateTimeField"":null,""DateTimeOffsetField"":null,""PostField"":null}", result);

      t = new NullableDateTimeTestClass()
      {
        DateTimeField = new DateTime(2000, 12, 15, 22, 11, 3, 55, DateTimeKind.Utc),
        DateTimeOffsetField = new DateTimeOffset(2000, 12, 15, 22, 11, 3, 55, TimeSpan.Zero)
      };

      result = JsonConvert.SerializeObject(t, converter);
      Assert.AreEqual(@"{""PreField"":null,""DateTimeField"":new Date(976918263055),""DateTimeOffsetField"":new Date(976918263055),""PostField"":null}", result);
    }
        public void NullableSerializeUTC()
        {
            NullableDateTimeTestClass c = new NullableDateTimeTestClass();
            c.DateTimeField = new DateTime(2008, 12, 12, 12, 12, 12, 0, DateTimeKind.Utc).ToLocalTime();
            c.DateTimeOffsetField = new DateTime(2008, 12, 12, 12, 12, 12, 0, DateTimeKind.Utc).ToLocalTime();
            c.PreField = "Pre";
            c.PostField = "Post";
            string json = JsonConvert.SerializeObject(c, new IsoDateTimeConverter() { DateTimeStyles = DateTimeStyles.AssumeUniversal });
            Assert.AreEqual(@"{""PreField"":""Pre"",""DateTimeField"":""2008-12-12T12:12:12Z"",""DateTimeOffsetField"":""2008-12-12T12:12:12+00:00"",""PostField"":""Post""}", json);

            //test the other edge case too
            c.DateTimeField = null;
            c.DateTimeOffsetField = null;
            c.PreField = "Pre";
            c.PostField = "Post";
            json = JsonConvert.SerializeObject(c, new IsoDateTimeConverter() { DateTimeStyles = DateTimeStyles.AssumeUniversal });
            Assert.AreEqual(@"{""PreField"":""Pre"",""DateTimeField"":null,""DateTimeOffsetField"":null,""PostField"":""Post""}", json);
        }