TODO list for Perl module DateTime::Event::Recurrence

"ICAL FORMAT"

* tests with ICal format, using
  DateTime::Format::ICal->format_recurrence():
    wkst
    interval
    start date
    monthly, week + day (is it day-of-week or day-of-month?)

* it should not generate an ICal string if it finds an invalid WKST or
  if it specify nanoseconds

* move class DateTime::Set::ICal to a separate file

OTHER

* add more tests with 'interval' > 1

* add more 'previous' tests

* find out how it behaves with mixed timezones and DST changes

* allow interleaved neg/positive values
    my $month = monthly DateTime::Event::Recurrence (
        days => [ -1, 31, 15 ],
        minutes => [ 30 ] );
  DONE - check if it is tested

* add more argument overflow tests:
  day in year, 
  week in year, 
  negative values, 
  ... 

