Check the bug causing situation: the special Australia/Lord_Howe time zone. toDateTime and toString functions are all tested at once
1554559200	2019-04-07 01:00:00	2019-04-07 01:00:00
1554559800	2019-04-07 01:10:00	2019-04-07 01:10:00
1554560400	2019-04-07 01:20:00	2019-04-07 01:20:00
1554561000	2019-04-07 01:30:00	2019-04-07 01:30:00
1554561600	2019-04-07 01:40:00	2019-04-07 01:40:00
1554562200	2019-04-07 01:50:00	2019-04-07 01:50:00
1554562800	2019-04-07 01:30:00	2019-04-07 01:30:00
1554563400	2019-04-07 01:40:00	2019-04-07 01:40:00
1554564000	2019-04-07 01:50:00	2019-04-07 01:50:00
1554564600	2019-04-07 02:00:00	2019-04-07 02:00:00
1554565200	2019-04-07 02:10:00	2019-04-07 02:10:00
1554565800	2019-04-07 02:20:00	2019-04-07 02:20:00
1554566400	2019-04-07 02:30:00	2019-04-07 02:30:00
1554567000	2019-04-07 02:40:00	2019-04-07 02:40:00
1554567600	2019-04-07 02:50:00	2019-04-07 02:50:00
1554568200	2019-04-07 03:00:00	2019-04-07 03:00:00
1554568800	2019-04-07 03:10:00	2019-04-07 03:10:00
1554569400	2019-04-07 03:20:00	2019-04-07 03:20:00
1554570000	2019-04-07 03:30:00	2019-04-07 03:30:00
1554570600	2019-04-07 03:40:00	2019-04-07 03:40:00
4 days test in batch comparing with manually computation result for Europe/Moscow whose timezone epoc is of whole hour:
4 days test in batch comparing with manually computation result for Asia/Tehran whose timezone epoc is of half hour:
4 days test in batch comparing with manually computation result for Australia/Lord_Howe whose timezone epoc is of half hour and also its DST offset is half hour: