diff --git a/tests/smpp/smpp_test.ok b/tests/smpp/smpp_test.ok
index fd44804..feb75a6 100644
--- a/tests/smpp/smpp_test.ok
+++ b/tests/smpp/smpp_test.ok
@@ -1 +1,9 @@
 Testing coding scheme support
+Testing SMPP time format parser
+'': 0 == 1970-01-01 00:00:00
+'220517175524000+': 1652810124 == 2022-05-17 17:55:24
+'220517175524000-': 1652810124 == 2022-05-17 17:55:24
+'220517175524004+': 1652806524 == 2022-05-17 16:55:24
+'220517175524004-': 1652813724 == 2022-05-17 18:55:24
+'000000010000000R': 1652749200 == 2022-05-17 01:00:00
+'000001000000000R': 1652832000 == 2022-05-18 00:00:00