public void ConvertFromUnixTimeAndBack() { // Arrange: var dateTime1 = new DateTime(2021, 05, 01, 10, 40, 00, DateTimeKind.Utc); dateTime1 = dateTime1.AddMilliseconds(123); // Act: var unixTime = DateTimeUtilities.ConvertDateTimeToUnixTime(dateTime1); var dateTime2 = DateTimeUtilities.ConvertUnixTimeToDateTime(unixTime); // Assert: Assert.AreEqual(dateTime1, dateTime2); }