public void AddQuarters() { var date = new DateTimeOffset(2013, 7, 26, 0, 0, 0, DateTimeOffset.Now.Offset); Assert.AreEqual(new DateTimeOffset(2014, 1, 26, 0, 0, 0, DateTimeOffset.Now.Offset), date.AddQuarters(2)); Assert.AreEqual(new DateTimeOffset(2013, 1, 26, 0, 0, 0, DateTimeOffset.Now.Offset), date.AddQuarters(-2)); }