public static IEnumerable<object[]> Subtract_TimeSpan_TestData()
{
var dateTimeOffset = new DateTimeOffset(new DateTime(2012, 6, 18, 10, 5, 1, 0, DateTimeKind.Utc));
yield return new object[] { dateTimeOffset, new TimeSpan(10, 5, 1), new DateTimeOffset(new DateTime(2012, 6, 18, 0, 0, 0, 0, DateTimeKind.Utc)) };
yield return new object[] { dateTimeOffset, new TimeSpan(-10, -5, -1), new DateTimeOffset(new DateTime(2012, 6, 18, 20, 10, 2, 0, DateTimeKind.Utc)) };
}