test/utc_arithmetic.exp

   1 09-06-2019 00:00:00 + 05-03-6 00:00:00 = 14-09-2025 00:00:00
   2 09-06-2019 00:00:00 + 30-11-3 00:00:00 = 08-06-2023 00:00:00
   3 22-07-2019 00:00:00 += 30-11-3 00:00:00 = 22-07-2023 00:00:00
   4 PASS utc_arithmetic (exit status: 0)