ical-recurrence: test that ByWeekNo with a numeric ByDay stays on that week day
byEveryWeekDayWeek silently drops every Specific ByDay, and when
nothing is left the BYWEEKNO branch of yearlyDayCandidate falls back to
all of Monday to Sunday. BYWEEKNO=20;BYDAY=2MO therefore yields all
seven days of week 20 rather than a Monday.
The rule does not conform, so the numeric part may be reported as a
fixable error or ignored, the way filterEvery reports it for the
frequencies that do not allow it at all. But no reading of the rule
puts an occurrence on a Wednesday, and today nothing is reported
either.
This asserts only the part that is independent of how the
non-conformance is resolved.