ical-recurrence: test that a weekly BySetPos does not depend on the limit The limit is an implementation detail of this library, not part of the recurrence rule, so it must only cut off results. It must not change which instance BYSETPOS selects. weeklyDateTimeRecurrence has its 'd <= limit' guard inside the list that filterSetPos numbers, so in the week that straddles the limit the candidate set is truncated and BYSETPOS picks from the truncated set. monthlyDateTimeRecurrence and yearlyDateTimeRecurrence have the same problem; dailyDateTimeRecurrence does not, because there filterSetPos only ever spans the times within one day. The last week day of the week of the 20th of January 2020 is Friday the 24th, which lies beyond a limit of the 22nd, so the recurrence set up to that limit contains no instance in that week at all.