public void Subtract() { TimeZoneInfo utc = TimeZoneInfo.FindSystemTimeZoneById("UTC"); EssentialsTime value = new EssentialsTime(2022, 4, 25, 7, 55, 0, utc); EssentialsTime result = value.Subtract(TimeSpan.FromMinutes(5)); Assert.AreEqual(value.TimeZone, result.TimeZone); }