Bug - Invalid recurring event occurrences after New Year

[AdamPodsiadlo]

Creating recurring event which is repeated every two weeks for all week days and starts in the middle of the week, is supposed to return occurrences until Sunday and then skips next week.

But when week ends on 31.12.2017 then occurrences for first week of the year are created.

Steps to reproduce:

1. Add event with following RRULE:
   FREQ=WEEKLY;INTERVAL=2;BYDAY=MO,TU,WE,TH,FR,SA,SU
2. Set event start to 30.12.2017
3. Set event end to 29.01.2018
4. Get event occurrences.

Actual result:

1. 30.12.2017, 31.12.2017, 01.01.2018, 02.01.2018, 03.01.2018, 04.01.2018, 05.01.2018, 08.01.2018,
   09.01.2018, 10.01.2018, 11.01.2018, 12.01.2018, 13.01.2018, 14.01.2018, 22.01.2018, 23.01.2018,
   24.01.2018, 25.01.2018, 26.01.2018, 27.01.2018, 28.01.2018
2. Extra invalid dates: 01.01.2018, 02.01.2018, 03.01.2018, 04.01.2018, 05.01.2018

Expeted result:
30.12.2017, 31.12.2017, 08.01.2018, 09.01.2018, 10.01.2018, 11.01.2018, 12.01.2018, 13.01.2018, 14.01.2018, 22.01.2018, 23.01.2018, 24.01.2018, 25.01.2018, 26.01.2018, 27.01.2018, 28.01.2018

UT:

    [TestFixture]
    public class Tests
    {
        private static void CheckDates(DateTime startDate, DateTime endDate, DateTime[] expectedDates)
        {
            var rule = new RecurrencePattern(FrequencyType.Weekly, 2);

            rule.ByDay = new List<WeekDay>()
            {
                new WeekDay(DayOfWeek.Monday),
                new WeekDay(DayOfWeek.Tuesday),
                new WeekDay(DayOfWeek.Wednesday),
                new WeekDay(DayOfWeek.Thursday),
                new WeekDay(DayOfWeek.Friday),
                new WeekDay(DayOfWeek.Saturday),
                new WeekDay(DayOfWeek.Sunday),
            };

            var calendarEvent = new CalendarEvent()
            {
                DtStart = new CalDateTime(startDate),
                DtEnd = new CalDateTime(endDate),
                RecurrenceRules = new List<RecurrencePattern>()
                {
                    rule
                },
            };

            var occurences = calendarEvent.GetOccurrences(startDate, endDate);

            var occurrencesDates = occurences.Select(o => o.Period.StartTime.Date).ToArray();

            CollectionAssert.AreEquivalent(expectedDates, occurrencesDates);
        }

        [Test]
        public void NewYear_EachOtherWeek()
        {
            var startDate = new DateTime(2017,12,30);
            var endDate = new DateTime(2018,1, 29);
            var expectedDates = new[]
            {
                new DateTime(2017, 12, 30),
                new DateTime(2017, 12, 31),

                // 1-7 no events
                
                new DateTime(2018, 1, 8),
                new DateTime(2018, 1, 9),
                new DateTime(2018, 1, 10),
                new DateTime(2018, 1, 11),
                new DateTime(2018, 1, 12),
                new DateTime(2018, 1, 13),
                new DateTime(2018, 1, 14),

                // 15 - 21 no events

                new DateTime(2018, 1, 22),
                new DateTime(2018, 1, 23),
                new DateTime(2018, 1, 24),
                new DateTime(2018, 1, 25),
                new DateTime(2018, 1, 26),
                new DateTime(2018, 1, 27),
                new DateTime(2018, 1, 28),
            };

            //FAILS
            CheckDates(startDate, endDate, expectedDates);
        }

        [Test]
        public void December_EachOtherWeek()
        {
            var startDate = new DateTime(2017, 12, 1);
            var endDate = new DateTime(2017, 12, 31);
            var expectedDates = new[]
            {
                new DateTime(2017, 12, 1),
                new DateTime(2017, 12, 2),
                new DateTime(2017, 12, 3),
                // 4-10 no events
                
                new DateTime(2017, 12, 11),
                new DateTime(2017, 12, 12),
                new DateTime(2017, 12, 13),
                new DateTime(2017, 12, 14),
                new DateTime(2017, 12, 15),
                new DateTime(2017, 12, 16),
                new DateTime(2017, 12, 17),

                // 18 - 24 no events

                new DateTime(2017, 12, 25),
                new DateTime(2017, 12, 26),
                new DateTime(2017, 12, 27),
                new DateTime(2017, 12, 28),
                new DateTime(2017, 12, 29),
                new DateTime(2017, 12, 30),
               // new DateTime(2017, 12, 31), 
            };

            //PASS
            CheckDates(startDate, endDate, expectedDates);
        }

        [Test]
        public void NovemberEnd_December_EachOtherWeek()
        {
            var startDate = new DateTime(2017, 11, 30);
            var endDate = new DateTime(2017, 12, 31);
            var expectedDates = new[]
            {
                new DateTime(2017, 11, 30),
                new DateTime(2017, 12, 1),
                new DateTime(2017, 12, 2),
                new DateTime(2017, 12, 3),
                // 4-10 no events
                
                new DateTime(2017, 12, 11),
                new DateTime(2017, 12, 12),
                new DateTime(2017, 12, 13),
                new DateTime(2017, 12, 14),
                new DateTime(2017, 12, 15),
                new DateTime(2017, 12, 16),
                new DateTime(2017, 12, 17),

                // 18 - 24 no events

                new DateTime(2017, 12, 25),
                new DateTime(2017, 12, 26),
                new DateTime(2017, 12, 27),
                new DateTime(2017, 12, 28),
                new DateTime(2017, 12, 29),
                new DateTime(2017, 12, 30),               
            };

            // PASS
            CheckDates(startDate, endDate, expectedDates);
        }
    }

[rianjs]

Creating recurring event which is repeated every two weeks for all week days and starts in the middle of the week, is supposed to return occurrences until Sunday and then skips next week.

But when week ends on 31.12.2017 then occurrences for first week of the year are created.

Steps to reproduce:

Add event with following RRULE:
FREQ=WEEKLY;INTERVAL=2;BYDAY=MO,TU,WE,TH,FR,SA,SU
**Set event start to 30.12.2017**
**Set event end to 29.01.2018**

Did you mean to create an event that's 30 days long, and recurs every other week creating a cascade of overlaps? You might want to check your expectations with respect to behavior for the event that's 30 days long...

[rianjs]

OK, I see what you mean.