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