diff --git a/src/parser/calendar/data/__tests__/PhutilCalendarRecurrenceRuleTestCase.php b/src/parser/calendar/data/__tests__/PhutilCalendarRecurrenceRuleTestCase.php
index 18912b4..02061f6 100644
--- a/src/parser/calendar/data/__tests__/PhutilCalendarRecurrenceRuleTestCase.php
+++ b/src/parser/calendar/data/__tests__/PhutilCalendarRecurrenceRuleTestCase.php
@@ -1,1166 +1,1555 @@
 <?php
 
 final class PhutilCalendarRecurrenceRuleTestCase extends PhutilTestCase {
 
   public function testSimpleRecurrenceRules() {
     $start = PhutilCalendarAbsoluteDateTime::newFromISO8601('20160101T120000Z');
 
     $rrule = id(new PhutilCalendarRecurrenceRule())
       ->setStartDateTime($start)
       ->setFrequency(PhutilCalendarRecurrenceRule::FREQUENCY_DAILY);
 
     $set = id(new PhutilCalendarRecurrenceSet())
       ->addSource($rrule);
 
     $result = $set->getEventsBetween(null, null, 3);
 
     $expect = array(
       PhutilCalendarAbsoluteDateTime::newFromISO8601('20160101T120000Z'),
       PhutilCalendarAbsoluteDateTime::newFromISO8601('20160102T120000Z'),
       PhutilCalendarAbsoluteDateTime::newFromISO8601('20160103T120000Z'),
     );
 
     $this->assertEqual(
       mpull($expect, 'getISO8601'),
       mpull($result, 'getISO8601'),
       pht('Simple daily event.'));
 
 
 
     $rrule = id(new PhutilCalendarRecurrenceRule())
       ->setStartDateTime($start)
       ->setFrequency(PhutilCalendarRecurrenceRule::FREQUENCY_HOURLY)
       ->setByHour(array(12, 13));
 
     $set = id(new PhutilCalendarRecurrenceSet())
       ->addSource($rrule);
 
     $result = $set->getEventsBetween(null, null, 5);
 
     $expect = array(
       PhutilCalendarAbsoluteDateTime::newFromISO8601('20160101T120000Z'),
       PhutilCalendarAbsoluteDateTime::newFromISO8601('20160101T130000Z'),
       PhutilCalendarAbsoluteDateTime::newFromISO8601('20160102T120000Z'),
       PhutilCalendarAbsoluteDateTime::newFromISO8601('20160102T130000Z'),
       PhutilCalendarAbsoluteDateTime::newFromISO8601('20160103T120000Z'),
     );
 
     $this->assertEqual(
       mpull($expect, 'getISO8601'),
       mpull($result, 'getISO8601'),
       pht('Hourly event with BYHOUR.'));
 
 
     $rrule = id(new PhutilCalendarRecurrenceRule())
       ->setStartDateTime($start)
       ->setFrequency(PhutilCalendarRecurrenceRule::FREQUENCY_YEARLY);
 
     $set = id(new PhutilCalendarRecurrenceSet())
       ->addSource($rrule);
 
     $result = $set->getEventsBetween(null, null, 2);
 
     $expect = array(
       PhutilCalendarAbsoluteDateTime::newFromISO8601('20160101T120000Z'),
       PhutilCalendarAbsoluteDateTime::newFromISO8601('20170101T120000Z'),
     );
 
     $this->assertEqual(
       mpull($expect, 'getISO8601'),
       mpull($result, 'getISO8601'),
       pht('Yearly event.'));
 
 
     // This is an efficiency test for bizarre rules: it defines a secondly
     // event which only occurs one a year, and generates 3 instances of it.
     // This implementation should be fast enough that this test doesn't take
     // a significant amount of time.
 
     $rrule = id(new PhutilCalendarRecurrenceRule())
       ->setStartDateTime($start)
       ->setFrequency(PhutilCalendarRecurrenceRule::FREQUENCY_SECONDLY)
       ->setByMonth(array(1))
       ->setByMonthDay(array(1))
       ->setByHour(array(12))
       ->setByMinute(array(0))
       ->setBySecond(array(0));
 
     $set = id(new PhutilCalendarRecurrenceSet())
       ->addSource($rrule);
 
     $result = $set->getEventsBetween(null, null, 3);
 
     $expect = array(
       PhutilCalendarAbsoluteDateTime::newFromISO8601('20160101T120000Z'),
       PhutilCalendarAbsoluteDateTime::newFromISO8601('20170101T120000Z'),
       PhutilCalendarAbsoluteDateTime::newFromISO8601('20180101T120000Z'),
     );
 
     $this->assertEqual(
       mpull($expect, 'getISO8601'),
       mpull($result, 'getISO8601'),
       pht('Secondly event with many constraints.'));
   }
 
   public function testYearlyRecurrenceRules() {
     $tests = array();
     $expect = array();
 
     $tests[] = array();
     $expect[] = array(
       '19970902',
       '19980902',
       '19990902',
     );
 
     $tests[] = array(
       'INTERVAL' => 2,
     );
     $expect[] = array(
       '19970902',
       '19990902',
       '20010902',
     );
 
     $tests[] = array(
       'DTSTART' => '20000229',
     );
     $expect[] = array(
       '20000229',
       '20040229',
       '20080229',
     );
 
     $tests[] = array(
       'BYMONTH' => array(1, 3),
     );
     $expect[] = array(
       '19980102',
       '19980302',
       '19990102',
     );
 
     $tests[] = array(
       'BYMONTHDAY' => array(1, 3),
     );
     $expect[] = array(
       '19970903',
       '19971001',
       '19971003',
     );
 
     $tests[] = array(
       'BYMONTH' => array(1, 3),
       'BYMONTHDAY' => array(5, 7),
     );
     $expect[] = array(
       '19980105',
       '19980107',
       '19980305',
     );
 
     $tests[] = array(
       'BYDAY' => array('TU', 'TH'),
     );
     $expect[] = array(
       '19970902',
       '19970904',
       '19970909',
     );
 
     $tests[] = array(
       'BYDAY' => array('SU'),
     );
     $expect[] = array(
       '19970907',
       '19970914',
       '19970921',
     );
 
     $tests[] = array(
       'BYMONTH' => array(1, 3),
       'BYDAY' => array('TU', 'TH'),
     );
     $expect[] = array(
       '19980101',
       '19980106',
       '19980108',
     );
 
     $tests[] = array(
       'BYMONTHDAY' => array(1, 3),
       'BYDAY' => array('TU', 'TH'),
     );
     $expect[] = array(
       '19980101',
       '19980203',
       '19980303',
     );
 
     $tests[] = array(
       'BYMONTHDAY' => array(1, 3),
       'BYDAY' => array('TU', 'TH'),
       'BYMONTH' => array(1, 3),
     );
     $expect[] = array(
       '19980101',
       '19980303',
       '20010301',
     );
 
     $tests[] = array(
       'BYDAY' => array('1TU', '-1TH'),
     );
     $expect[] = array(
       '19971225',
       '19980106',
       '19981231',
     );
 
     // Same test as above, just making sure the optional "+" syntax works.
     $tests[] = array(
       'BYDAY' => array('+1TU', '-1TH'),
     );
     $expect[] = array(
       '19971225',
       '19980106',
       '19981231',
     );
 
     $tests[] = array(
       'BYDAY' => array('3TU', '-3TH'),
     );
     $expect[] = array(
       '19971211',
       '19980120',
       '19981217',
     );
 
     $tests[] = array(
       'BYMONTH' => array(1, 3),
       'BYDAY' => array('1TU', '-1TH'),
     );
     $expect[] = array(
       '19980106',
       '19980129',
       '19980303',
     );
 
     $tests[] = array(
       'BYMONTH' => array(1, 3),
       'BYDAY' => array('3TU', '-3TH'),
     );
     $expect[] = array(
       '19980115',
       '19980120',
       '19980312',
     );
 
     $tests[] = array(
       'BYYEARDAY' => array(1, 100, 200, 365),
       'COUNT' => 4,
     );
     $expect[] = array(
       '19971231',
       '19980101',
       '19980410',
       '19980719',
     );
 
     $tests[] = array(
       'BYYEARDAY' => array(-365, -266, -166, -1),
       'COUNT' => 4,
     );
     $expect[] = array(
       '19971231',
       '19980101',
       '19980410',
       '19980719',
     );
 
     $tests[] = array(
       'BYYEARDAY' => array(1, 100, 200, 365),
       'BYMONTH' => array(4, 7),
       'COUNT' => 4,
     );
     $expect[] = array(
       '19980410',
       '19980719',
       '19990410',
       '19990719',
     );
 
     $tests[] = array(
       'BYYEARDAY' => array(-365, -266, -166, -1),
       'BYMONTH' => array(4, 7),
       'COUNT' => 4,
     );
     $expect[] = array(
       '19980410',
       '19980719',
       '19990410',
       '19990719',
     );
 
     $tests[] = array(
       'BYWEEKNO' => array(20),
     );
     $expect[] = array(
       '19980511',
       '19980512',
       '19980513',
     );
 
     $tests[] = array(
       'BYWEEKNO' => array(1),
       'BYDAY' => array('MO'),
     );
     $expect[] = array(
       '19971229',
       '19990104',
       '20000103',
     );
 
     $tests[] = array(
       'BYWEEKNO' => array(52),
       'BYDAY' => array('SU'),
     );
     $expect[] = array(
       '19971228',
       '19981227',
       '20000102',
     );
 
     $tests[] = array(
       'BYWEEKNO' => array(-1),
       'BYDAY' => array('SU'),
     );
     $expect[] = array(
       '19971228',
       '19990103',
       '20000102',
     );
 
     $tests[] = array(
       'BYWEEKNO' => array(53),
       'BYDAY' => array('MO'),
     );
     $expect[] = array(
       '19981228',
       '20041227',
       '20091228',
     );
 
     $tests[] = array(
       'BYHOUR' => array(6, 18),
     );
     $expect[] = array(
       '19970902T060000Z',
       '19970902T180000Z',
       '19980902T060000Z',
     );
 
     $tests[] = array(
       'BYMINUTE' => array(15, 30),
     );
     $expect[] = array(
       '19970902T001500Z',
       '19970902T003000Z',
       '19980902T001500Z',
     );
 
     $tests[] = array(
       'BYSECOND' => array(10, 20),
     );
     $expect[] = array(
       '19970902T000010Z',
       '19970902T000020Z',
       '19980902T000010Z',
     );
 
     $tests[] = array(
       'BYHOUR' => array(6, 18),
       'BYMINUTE' => array(15, 30),
     );
     $expect[] = array(
       '19970902T061500Z',
       '19970902T063000Z',
       '19970902T181500Z',
     );
 
     $tests[] = array(
       'BYHOUR' => array(6, 18),
       'BYSECOND' => array(10, 20),
     );
     $expect[] = array(
       '19970902T060010Z',
       '19970902T060020Z',
       '19970902T180010Z',
     );
 
     $tests[] = array(
       'BYMINUTE' => array(15, 30),
       'BYSECOND' => array(10, 20),
     );
     $expect[] = array(
       '19970902T001510Z',
       '19970902T001520Z',
       '19970902T003010Z',
     );
 
     $tests[] = array(
       'BYHOUR' => array(6, 18),
       'BYMINUTE' => array(15, 30),
       'BYSECOND' => array(10, 20),
     );
     $expect[] = array(
       '19970902T061510Z',
       '19970902T061520Z',
       '19970902T063010Z',
     );
 
     $tests[] = array(
       'BYMONTHDAY' => array(15),
       'BYHOUR' => array(6, 18),
       'BYSETPOS' => array(3, -3),
     );
     $expect[] = array(
       '19971115T180000Z',
       '19980215T060000Z',
       '19981115T180000Z',
     );
 
     $this->assertRules(
       array(
         'FREQ' => 'YEARLY',
         'COUNT' => 3,
         'DTSTART' => '19970902',
       ),
       $tests,
       $expect);
   }
 
   public function testMonthlyRecurrenceRules() {
     $tests = array();
     $expect = array();
 
     $tests[] = array();
     $expect[] = array(
       '19970902',
       '19971002',
       '19971102',
     );
 
     $tests[] = array(
       'INTERVAL' => 2,
     );
     $expect[] = array(
       '19970902',
       '19971102',
       '19980102',
     );
 
     $tests[] = array(
       'INTERVAL' => 18,
     );
     $expect[] = array(
       '19970902',
       '19990302',
       '20000902',
     );
 
     $tests[] = array(
       'BYMONTH' => array(1, 3),
     );
     $expect[] = array(
       '19980102',
       '19980302',
       '19990102',
     );
 
     $tests[] = array(
       'BYMONTHDAY' => array(1, 3),
     );
     $expect[] = array(
       '19970903',
       '19971001',
       '19971003',
     );
 
     $tests[] = array(
       'BYMONTHDAY' => array(5, 7),
       'BYMONTH' => array(1, 3),
     );
     $expect[] = array(
       '19980105',
       '19980107',
       '19980305',
     );
 
     $tests[] = array(
       'BYDAY' => array('TU', 'TH'),
     );
     $expect[] = array(
       '19970902',
       '19970904',
       '19970909',
     );
 
     $tests[] = array(
       'BYDAY' => array('3MO'),
     );
     $expect[] = array(
       '19970915',
       '19971020',
       '19971117',
     );
 
     $tests[] = array(
       'BYDAY' => array('1TU', '-1TH'),
     );
     $expect[] = array(
       '19970902',
       '19970925',
       '19971007',
     );
 
     $tests[] = array(
       'BYDAY' => array('3TU', '-3TH'),
     );
     $expect[] = array(
       '19970911',
       '19970916',
       '19971016',
     );
 
     $tests[] = array(
       'BYDAY' => array('TU', 'TH'),
       'BYMONTH' => array(1, 3),
     );
     $expect[] = array(
       '19980101',
       '19980106',
       '19980108',
     );
 
     $tests[] = array(
       'BYMONTH' => array(1, 3),
       'BYDAY' => array('1TU', '-1TH'),
     );
     $expect[] = array(
       '19980106',
       '19980129',
       '19980303',
     );
 
     $tests[] = array(
       'BYMONTH' => array(1, 3),
       'BYDAY' => array('3TU', '-3TH'),
     );
     $expect[] = array(
       '19980115',
       '19980120',
       '19980312',
     );
 
     $tests[] = array(
       'BYMONTHDAY' => array(1, 3),
       'BYDAY' => array('TU', 'TH'),
     );
     $expect[] = array(
       '19980101',
       '19980203',
       '19980303',
     );
 
     $tests[] = array(
       'BYMONTH' => array(1, 3),
       'BYMONTHDAY' => array(1, 3),
       'BYDAY' => array('TU', 'TH'),
     );
     $expect[] = array(
       '19980101',
       '19980303',
       '20010301',
     );
 
     $tests[] = array(
       'BYDAY' => array('MO', 'TU', 'WE', 'TH', 'FR'),
       'BYSETPOS' => array(-1),
     );
     $expect[] = array(
       '19970930',
       '19971031',
       '19971128',
     );
 
     $tests[] = array(
       'BYDAY' => array('1MO', '1TU', '1WE', '1TH', '1FR', '-1FR'),
       'BYMONTHDAY' => array(1, -1, -2),
     );
     $expect[] = array(
       '19971001',
       '19971031',
       '19971201',
     );
 
     $tests[] = array(
       'BYDAY' => array('1MO', '1TU', '1WE', '1TH', 'FR'),
       'BYMONTHDAY' => array(1, -1, -2),
     );
     $expect[] = array(
       '19971001',
       '19971031',
       '19971201',
     );
 
     $tests[] = array(
       'BYHOUR' => array(6, 18),
     );
     $expect[] = array(
       '19970902T060000Z',
       '19970902T180000Z',
       '19971002T060000Z',
     );
 
     $tests[] = array(
       'BYMINUTE' => array(6, 18),
     );
     $expect[] = array(
       '19970902T000600Z',
       '19970902T001800Z',
       '19971002T000600Z',
     );
 
     $tests[] = array(
       'BYSECOND' => array(6, 18),
     );
     $expect[] = array(
       '19970902T000006Z',
       '19970902T000018Z',
       '19971002T000006Z',
     );
 
     $tests[] = array(
       'BYMONTHDAY' => array(13, 17),
       'BYHOUR' => array(6, 18),
       'BYSETPOS' => array(3, -3),
     );
     $expect[] = array(
       '19970913T180000Z',
       '19970917T060000Z',
       '19971013T180000Z',
     );
 
     $tests[] = array(
       'BYMONTHDAY' => array(13, 17),
       'BYHOUR' => array(6, 18),
       'BYSETPOS' => array(3, 3, -3),
     );
     $expect[] = array(
       '19970913T180000Z',
       '19970917T060000Z',
       '19971013T180000Z',
     );
 
     $tests[] = array(
       'BYMONTHDAY' => array(13, 17),
       'BYHOUR' => array(6, 18),
       'BYSETPOS' => array(4, -1),
     );
     $expect[] = array(
       '19970917T180000Z',
       '19971017T180000Z',
       '19971117T180000Z',
     );
 
     $this->assertRules(
       array(
         'FREQ' => 'MONTHLY',
         'COUNT' => 3,
         'DTSTART' => '19970902',
       ),
       $tests,
       $expect);
   }
 
   public function testDailyRecurrenceRules() {
     $tests = array();
     $expect = array();
 
     $tests[] = array();
     $expect[] = array(
       '19970902',
       '19970903',
       '19970904',
     );
 
     $tests[] = array(
       'INTERVAL' => 2,
     );
     $expect[] = array(
       '19970902',
       '19970904',
       '19970906',
     );
 
     $tests[] = array(
       'INTERVAL' => 92,
     );
     $expect[] = array(
       '19970902',
       '19971203',
       '19980305',
     );
 
     $tests[] = array(
       'BYMONTH' => array(1, 3),
     );
     $expect[] = array(
       '19980101',
       '19980102',
       '19980103',
     );
 
     // This is testing that INTERVAL is respected in the presence of a BYMONTH
     // filter which skips some months.
     $tests[] = array(
       'BYMONTH' => array(12),
       'INTERVAL' => 17,
     );
     $expect[] = array(
       '19971213',
       '19971230',
       '19981205',
     );
 
     $tests[] = array(
       'BYMONTHDAY' => array(1, 3),
     );
     $expect[] = array(
       '19970903',
       '19971001',
       '19971003',
     );
 
     $tests[] = array(
       'BYMONTH' => array(1, 3),
       'BYMONTHDAY' => array(5, 7),
     );
     $expect[] = array(
       '19980105',
       '19980107',
       '19980305',
     );
 
     $tests[] = array(
       'BYDAY' => array('TU', 'TH'),
     );
     $expect[] = array(
       '19970902',
       '19970904',
       '19970909',
     );
 
     $tests[] = array(
       'BYMONTH' => array(1, 3),
       'BYDAY' => array('TU', 'TH'),
     );
     $expect[] = array(
       '19980101',
       '19980106',
       '19980108',
     );
 
     $tests[] = array(
       'BYMONTHDAY' => array(1, 3),
       'BYDAY' => array('TU', 'TH'),
     );
     $expect[] = array(
       '19980101',
       '19980203',
       '19980303',
     );
 
     $tests[] = array(
       'BYMONTH' => array(1, 3),
       'BYMONTHDAY' => array(1, 3),
       'BYDAY' => array('TU', 'TH'),
     );
     $expect[] = array(
       '19980101',
       '19980303',
       '20010301',
     );
 
     $tests[] = array(
       'BYHOUR' => array(6, 18),
       'BYMINUTE' => array(15, 45),
       'BYSETPOS' => array(3, -3),
       'DTSTART' => '19970902T090000Z',
     );
     $expect[] = array(
       '19970902T181500Z',
       '19970903T064500Z',
       '19970903T181500Z',
     );
 
     $this->assertRules(
       array(
         'FREQ' => 'DAILY',
         'COUNT' => 3,
         'DTSTART' => '19970902',
       ),
       $tests,
       $expect);
   }
 
   public function testHourlyRecurrenceRules() {
     $tests = array();
     $expect = array();
 
     $tests[] = array();
     $expect[] = array(
       '19970902T090000Z',
       '19970902T100000Z',
       '19970902T110000Z',
     );
 
     $tests[] = array(
       'INTERVAL' => 2,
     );
     $expect[] = array(
       '19970902T090000Z',
       '19970902T110000Z',
       '19970902T130000Z',
     );
 
     $tests[] = array(
       'INTERVAL' => 769,
     );
     $expect[] = array(
       '19970902T090000Z',
       '19971004T100000Z',
       '19971105T110000Z',
     );
 
     $tests[] = array(
       'BYMONTH' => array(1, 3),
     );
     $expect[] = array(
       '19980101T000000Z',
       '19980101T010000Z',
       '19980101T020000Z',
     );
 
     $tests[] = array(
       'BYMONTHDAY' => array(1, 3),
     );
     $expect[] = array(
       '19970903T000000Z',
       '19970903T010000Z',
       '19970903T020000Z',
     );
 
     $tests[] = array(
       'BYMONTH' => array(1, 3),
       'BYMONTHDAY' => array(5, 7),
     );
     $expect[] = array(
       '19980105T000000Z',
       '19980105T010000Z',
       '19980105T020000Z',
     );
 
     $tests[] = array(
       'BYDAY' => array('TU', 'TH'),
     );
     $expect[] = array(
       '19970902T090000Z',
       '19970902T100000Z',
       '19970902T110000Z',
     );
 
     $tests[] = array(
       'BYMONTH' => array(1, 3),
       'BYDAY' => array('TU', 'TH'),
     );
     $expect[] = array(
       '19980101T000000Z',
       '19980101T010000Z',
       '19980101T020000Z',
     );
 
     $tests[] = array(
       'BYMONTHDAY' => array(1, 3),
       'BYDAY' => array('TU', 'TH'),
     );
     $expect[] = array(
       '19980101T000000Z',
       '19980101T010000Z',
       '19980101T020000Z',
     );
 
     $tests[] = array(
       'BYMONTHDAY' => array(1, 3),
       'BYMONTH' => array(1, 3),
       'BYDAY' => array('TU', 'TH'),
     );
     $expect[] = array(
       '19980101T000000Z',
       '19980101T010000Z',
       '19980101T020000Z',
     );
 
     $tests[] = array(
       'COUNT' => 4,
       'BYYEARDAY' => array(1, 100, 200, 365),
     );
     $expect[] = array(
       '19971231T000000Z',
       '19971231T010000Z',
       '19971231T020000Z',
       '19971231T030000Z',
     );
 
     $tests[] = array(
       'COUNT' => 4,
       'BYYEARDAY' => array(-365, -266, -166, -1),
     );
     $expect[] = array(
       '19971231T000000Z',
       '19971231T010000Z',
       '19971231T020000Z',
       '19971231T030000Z',
     );
 
     $tests[] = array(
       'COUNT' => 4,
       'BYMONTH' => array(4, 7),
       'BYYEARDAY' => array(1, 100, 200, 365),
     );
     $expect[] = array(
       '19980410T000000Z',
       '19980410T010000Z',
       '19980410T020000Z',
       '19980410T030000Z',
     );
 
     $tests[] = array(
       'COUNT' => 4,
       'BYMONTH' => array(4, 7),
       'BYYEARDAY' => array(-365, -266, -166, -1),
     );
     $expect[] = array(
       '19980410T000000Z',
       '19980410T010000Z',
       '19980410T020000Z',
       '19980410T030000Z',
     );
 
     $tests[] = array(
       'BYHOUR' => array(6, 18),
     );
     $expect[] = array(
       '19970902T180000Z',
       '19970903T060000Z',
       '19970903T180000Z',
     );
 
     $tests[] = array(
       'BYMINUTE' => array(15, 45),
       'BYSECOND' => array(15, 45),
       'BYSETPOS' => array(3, -3),
     );
     $expect[] = array(
       '19970902T091545Z',
       '19970902T094515Z',
       '19970902T101545Z',
     );
 
     $this->assertRules(
       array(
         'FREQ' => 'HOURLY',
         'COUNT' => 3,
         'DTSTART' => '19970902T090000Z',
       ),
       $tests,
       $expect);
   }
 
   public function testMinutelyRecurrenceRules() {
     $tests = array();
     $expect = array();
 
     $tests[] = array(
     );
     $expect[] = array(
       '19970902T090000Z',
       '19970902T090100Z',
       '19970902T090200Z',
     );
 
     $tests[] = array(
       'INTERVAL' => 2,
     );
     $expect[] = array(
       '19970902T090000Z',
       '19970902T090200Z',
       '19970902T090400Z',
     );
 
     $tests[] = array(
       'BYHOUR' => array(6, 18),
       'BYMINUTE' => array(6, 18),
       'BYSECOND' => array(6, 18),
     );
     $expect[] = array(
       '19970902T180606Z',
       '19970902T180618Z',
       '19970902T181806Z',
     );
 
     $tests[] = array(
       'BYSECOND' => array(15, 30, 45),
       'BYSETPOS' => array(3, -3),
     );
     $expect[] = array(
       '19970902T090015Z',
       '19970902T090045Z',
       '19970902T090115Z',
     );
 
     $this->assertRules(
       array(
         'FREQ' => 'MINUTELY',
         'COUNT' => 3,
         'DTSTART' => '19970902T090000Z',
       ),
       $tests,
       $expect);
   }
 
   public function testSecondlyRecurrenceRules() {
     $tests = array();
     $expect = array();
 
     $tests[] = array();
     $expect[] = array(
       '19970902T090000Z',
       '19970902T090001Z',
       '19970902T090002Z',
     );
 
     $tests[] = array(
       'INTERVAL' => 2,
     );
     $expect[] = array(
       '19970902T090000Z',
       '19970902T090002Z',
       '19970902T090004Z',
     );
 
     $tests[] = array(
       'INTERVAL' => 90061,
     );
     $expect[] = array(
       '19970902T090000Z',
       '19970903T100101Z',
       '19970904T110202Z',
     );
 
     $tests[] = array(
       'BYSECOND' => array(0),
       'BYMINUTE' => array(1),
       'DTSTART' => '20100322T120100Z',
     );
     $expect[] = array(
       '20100322T120100Z',
       '20100322T130100Z',
       '20100322T140100Z',
     );
 
     $this->assertRules(
       array(
         'FREQ' => 'SECONDLY',
         'COUNT' => 3,
         'DTSTART' => '19970902T090000Z',
       ),
       $tests,
       $expect);
   }
 
+  public function testRFC5545RecurrenceRules() {
+    // These tests are derived from the examples in RFC5545.
+    $tests = array();
+    $expect = array();
+
+    $tests[] = array(
+      'FREQ' => 'DAILY',
+      'COUNT' => 10,
+      'DTSTART' => '19970902T090000Z',
+    );
+    $expect[] = array(
+      '19970902T090000Z',
+      '19970903T090000Z',
+      '19970904T090000Z',
+      '19970905T090000Z',
+      '19970906T090000Z',
+      '19970907T090000Z',
+      '19970908T090000Z',
+      '19970909T090000Z',
+      '19970910T090000Z',
+      '19970911T090000Z',
+    );
+
+    $tests[] = array(
+      'FREQ' => 'DAILY',
+      'INTERVAL' => 2,
+      'DTSTART' => '19970902T090000Z',
+      'COUNT' => 5,
+    );
+    $expect[] = array(
+      '19970902T090000Z',
+      '19970904T090000Z',
+      '19970906T090000Z',
+      '19970908T090000Z',
+      '19970910T090000Z',
+    );
+
+    $tests[] = array(
+      'FREQ' => 'YEARLY',
+      'BYMONTH' => array(1),
+      'BYDAY' => array('MO', 'TU', 'WE', 'TH', 'FR', 'SA', 'SU'),
+      'DTSTART' => '19970902T090000Z',
+      'COUNT' => 3,
+    );
+    $expect[] = array(
+      '19980101T090000Z',
+      '19980102T090000Z',
+      '19980103T090000Z',
+    );
+
+    $tests[] = array(
+      'FREQ' => 'MONTHLY',
+      'COUNT' => 3,
+      'BYDAY' => array('1FR'),
+      'DTSTART' => '19970902T090000Z',
+    );
+    $expect[] = array(
+      '19970905T090000Z',
+      '19971003T090000Z',
+      '19971107T090000Z',
+    );
+
+    $tests[] = array(
+      'FREQ' => 'MONTHLY',
+      'INTERVAL' => 2,
+      'COUNT' => 5,
+      'BYDAY' => array('1SU', '-1SU'),
+      'DTSTART' => '19970902T090000Z',
+    );
+    $expect[] = array(
+      '19970907T090000Z',
+      '19970928T090000Z',
+      '19971102T090000Z',
+      '19971130T090000Z',
+      '19980104T090000Z',
+    );
+
+    $tests[] = array(
+      'FREQ' => 'MONTHLY',
+      'COUNT' => 6,
+      'BYDAY' => array('-2MO'),
+      'DTSTART' => '19970902T090000Z',
+    );
+    $expect[] = array(
+      '19970922T090000Z',
+      '19971020T090000Z',
+      '19971117T090000Z',
+      '19971222T090000Z',
+      '19980119T090000Z',
+      '19980216T090000Z',
+    );
+
+    $tests[] = array(
+      'FREQ' => 'MONTHLY',
+      'COUNT' => 6,
+      'BYMONTHDAY' => array(-3),
+      'DTSTART' => '19970902T090000Z',
+    );
+    $expect[] = array(
+      '19970928T090000Z',
+      '19971029T090000Z',
+      '19971128T090000Z',
+      '19971229T090000Z',
+      '19980129T090000Z',
+      '19980226T090000Z',
+    );
+
+    $tests[] = array(
+      'FREQ' => 'MONTHLY',
+      'COUNT' => 5,
+      'BYMONTHDAY' => array(2, 15),
+      'DTSTART' => '19970902T090000Z',
+    );
+    $expect[] = array(
+      '19970902T090000Z',
+      '19970915T090000Z',
+      '19971002T090000Z',
+      '19971015T090000Z',
+      '19971102T090000Z',
+    );
+
+    $tests[] = array(
+      'FREQ' => 'MONTHLY',
+      'COUNT' => 5,
+      'BYMONTHDAY' => array(-1, 1),
+      'DTSTART' => '19970902T090000Z',
+    );
+    $expect[] = array(
+      '19970930T090000Z',
+      '19971001T090000Z',
+      '19971031T090000Z',
+      '19971101T090000Z',
+      '19971130T090000Z',
+    );
+
+    $tests[] = array(
+      'FREQ' => 'MONTHLY',
+      'COUNT' => 7,
+      'INTERVAL' => 18,
+      'BYMONTHDAY' => array(10, 11, 12, 13, 14, 15),
+      'DTSTART' => '19970902T090000Z',
+    );
+    $expect[] = array(
+      '19970910T090000Z',
+      '19970911T090000Z',
+      '19970912T090000Z',
+      '19970913T090000Z',
+      '19970914T090000Z',
+      '19970915T090000Z',
+      '19990310T090000Z',
+    );
+
+    $tests[] = array(
+      'FREQ' => 'MONTHLY',
+      'COUNT' => 6,
+      'INTERVAL' => 2,
+      'BYDAY' => array('TU'),
+      'DTSTART' => '19970902T090000Z',
+    );
+    $expect[] = array(
+      '19970902T090000Z',
+      '19970909T090000Z',
+      '19970916T090000Z',
+      '19970923T090000Z',
+      '19970930T090000Z',
+      '19971104T090000Z',
+    );
+
+    $tests[] = array(
+      'FREQ' => 'YEARLY',
+      'COUNT' => 10,
+      'BYMONTH' => array(6, 7),
+      'DTSTART' => '19970610T090000Z',
+    );
+    $expect[] = array(
+      '19970610T090000Z',
+      '19970710T090000Z',
+      '19980610T090000Z',
+      '19980710T090000Z',
+      '19990610T090000Z',
+      '19990710T090000Z',
+      '20000610T090000Z',
+      '20000710T090000Z',
+      '20010610T090000Z',
+      '20010710T090000Z',
+    );
+
+    $tests[] = array(
+      'FREQ' => 'YEARLY',
+      'COUNT' => 4,
+      'INTERVAL' => 3,
+      'BYYEARDAY' => array(1, 100, 200),
+      'DTSTART' => '19970101T090000Z',
+    );
+    $expect[] = array(
+      '19970101T090000Z',
+      '19970410T090000Z',
+      '19970719T090000Z',
+      '20000101T090000Z',
+    );
+
+    $tests[] = array(
+      'FREQ' => 'YEARLY',
+      'COUNT' => 3,
+      'BYDAY' => array('20MO'),
+      'DTSTART' => '19970519T090000Z',
+    );
+    $expect[] = array(
+      '19970519T090000Z',
+      '19980518T090000Z',
+      '19990517T090000Z',
+    );
+
+    $tests[] = array(
+      'FREQ' => 'YEARLY',
+      'COUNT' => 3,
+      'BYWEEKNO' => array(20),
+      'BYDAY' => array('MO'),
+      'DTSTART' => '19970512T090000Z',
+    );
+    $expect[] = array(
+      '19970512T090000Z',
+      '19980511T090000Z',
+      '19990517T090000Z',
+    );
+
+    $tests[] = array(
+      'FREQ' => 'YEARLY',
+      'BYDAY' => array('TH'),
+      'BYMONTH' => array(3),
+      'DTSTART' => '19970313T090000Z',
+      'COUNT' => 5,
+    );
+    $expect[] = array(
+      '19970313T090000Z',
+      '19970320T090000Z',
+      '19970327T090000Z',
+      '19980305T090000Z',
+      '19980312T090000Z',
+    );
+
+    $tests[] = array(
+      'FREQ' => 'YEARLY',
+      'BYDAY' => array('TH'),
+      'BYMONTH' => array(6, 7, 8),
+      'DTSTART' => '19970101T090000Z',
+      'COUNT' => 15,
+    );
+    $expect[] = array(
+      '19970605T090000Z',
+      '19970612T090000Z',
+      '19970619T090000Z',
+      '19970626T090000Z',
+      '19970703T090000Z',
+      '19970710T090000Z',
+      '19970717T090000Z',
+      '19970724T090000Z',
+      '19970731T090000Z',
+      '19970807T090000Z',
+      '19970814T090000Z',
+      '19970821T090000Z',
+      '19970828T090000Z',
+      '19980604T090000Z',
+      '19980611T090000Z',
+    );
+
+    $tests[] = array(
+      'FREQ' => 'YEARLY',
+      'BYDAY' => array('FR'),
+      'BYMONTHDAY' => array(13),
+      'COUNT' => 4,
+      'DTSTART' => '19970902T090000Z',
+    );
+    $expect[] = array(
+      '19980213T090000Z',
+      '19980313T090000Z',
+      '19981113T090000Z',
+      '19990813T090000Z',
+    );
+
+    $tests[] = array(
+      'FREQ' => 'MONTHLY',
+      'BYDAY' => array('SA'),
+      'BYMONTHDAY' => array(7, 8, 9, 10, 11, 12, 13),
+      'COUNT' => 10,
+      'DTSTART' => '19970902T090000Z',
+    );
+    $expect[] = array(
+      '19970913T090000Z',
+      '19971011T090000Z',
+      '19971108T090000Z',
+      '19971213T090000Z',
+      '19980110T090000Z',
+      '19980207T090000Z',
+      '19980307T090000Z',
+      '19980411T090000Z',
+      '19980509T090000Z',
+      '19980613T090000Z',
+    );
+
+    $tests[] = array(
+      'FREQ' => 'YEARLY',
+      'INTERVAL' => 4,
+      'BYMONTH' => array(11),
+      'BYDAY' => array('TU'),
+      'BYMONTHDAY' => array(2, 3, 4, 5, 6, 7, 8),
+      'COUNT' => 6,
+      'DTSTART' => '19961105T090000Z',
+    );
+    $expect[] = array(
+      '19961105T090000Z',
+      '20001107T090000Z',
+      '20041102T090000Z',
+      '20081104T090000Z',
+      '20121106T090000Z',
+      '20161108T090000Z',
+    );
+
+    $tests[] = array(
+      'FREQ' => 'MONTHLY',
+      'BYDAY' => array('TU', 'WE', 'TH'),
+      'BYSETPOS' => array(3),
+      'COUNT' => 3,
+      'DTSTART' => '19970904T090000Z',
+    );
+    $expect[] = array(
+      '19970904T090000Z',
+      '19971007T090000Z',
+      '19971106T090000Z',
+    );
+
+    $tests[] = array(
+      'FREQ' => 'MONTHLY',
+      'BYDAY' => array('MO', 'TU', 'WE', 'TH', 'FR'),
+      'BYSETPOS' => array(-2),
+      'COUNT' => 3,
+      'DTSTART' => '19970929T090000Z',
+    );
+    $expect[] = array(
+      '19970929T090000Z',
+      '19971030T090000Z',
+      '19971127T090000Z',
+    );
+
+    $tests[] = array(
+      'FREQ' => 'HOURLY',
+      'INTERVAL' => 3,
+      'DTSTART' => '19970929T090000Z',
+      'COUNT' => 3,
+    );
+    $expect[] = array(
+      '19970929T090000Z',
+      '19970929T120000Z',
+      '19970929T150000Z',
+    );
+
+    $tests[] = array(
+      'FREQ' => 'MINUTELY',
+      'INTERVAL' => 15,
+      'COUNT' => 6,
+      'DTSTART' => '19970902T090000Z',
+    );
+    $expect[] = array(
+      '19970902T090000Z',
+      '19970902T091500Z',
+      '19970902T093000Z',
+      '19970902T094500Z',
+      '19970902T100000Z',
+      '19970902T101500Z',
+    );
+
+    $tests[] = array(
+      'FREQ' => 'MINUTELY',
+      'INTERVAL' => 90,
+      'COUNT' => 4,
+      'DTSTART' => '19970902T090000Z',
+    );
+    $expect[] = array(
+      '19970902T090000Z',
+      '19970902T103000Z',
+      '19970902T120000Z',
+      '19970902T133000Z',
+    );
+
+
+    $this->assertRules(array(), $tests, $expect);
+  }
+
+
   private function assertRules(array $defaults, array $tests, array $expect) {
     foreach ($tests as $key => $test) {
       $options = $test + $defaults;
 
       $start = PhutilCalendarAbsoluteDateTime::newFromISO8601(
         $options['DTSTART']);
 
       $rrule = id(new PhutilCalendarRecurrenceRule())
         ->setStartDateTime($start)
         ->setFrequency($options['FREQ']);
 
       $interval = idx($options, 'INTERVAL');
       if ($interval) {
         $rrule->setInterval($interval);
       }
 
       $by_day = idx($options, 'BYDAY');
       if ($by_day) {
         $rrule->setByDay($by_day);
       }
 
       $by_month = idx($options, 'BYMONTH');
       if ($by_month) {
         $rrule->setByMonth($by_month);
       }
 
       $by_monthday = idx($options, 'BYMONTHDAY');
       if ($by_monthday) {
         $rrule->setByMonthDay($by_monthday);
       }
 
       $by_yearday = idx($options, 'BYYEARDAY');
       if ($by_yearday) {
         $rrule->setByYearDay($by_yearday);
       }
 
       $by_weekno = idx($options, 'BYWEEKNO');
       if ($by_weekno) {
         $rrule->setByWeekNumber($by_weekno);
       }
 
       $by_hour = idx($options, 'BYHOUR');
       if ($by_hour) {
         $rrule->setByHour($by_hour);
       }
 
       $by_minute = idx($options, 'BYMINUTE');
       if ($by_minute) {
         $rrule->setByMinute($by_minute);
       }
 
       $by_second = idx($options, 'BYSECOND');
       if ($by_second) {
         $rrule->setBySecond($by_second);
       }
 
       $by_setpos = idx($options, 'BYSETPOS');
       if ($by_setpos) {
         $rrule->setBySetPosition($by_setpos);
       }
 
       $set = id(new PhutilCalendarRecurrenceSet())
         ->addSource($rrule);
 
       $result = $set->getEventsBetween(null, null, $options['COUNT']);
 
       $this->assertEqual(
         $expect[$key],
         mpull($result, 'getISO8601'));
     }
   }
 
 
 }