Reword recurrence tests.

1 files changed, 292 insertions, 225 deletions

diff --git a/module/vcomponent/recurrence/display/test.scm b/module/vcomponent/recurrence/display/test.scm
index 3502cd5a..b0b2f258 100644
--- a/module/vcomponent/recurrence/display/test.scm
+++ b/module/vcomponent/recurrence/display/test.scm
@@ -5,232 +5,299 @@
 
 (use-modules (vcomponent recurrence display)
              (vcomponent recurrence parse)
-             (util))
+             (vcomponent recurrence generate-alt)
+             (vcomponent)
+             (datetime)
+             (datetime util)
+             (util)
+             (srfi srfi-41)
+             (srfi srfi-88)
+             )
 
 ;; Examples copied from RFC5545
 
-(define (run-test desc sources)
-  (format #t "~%> ~a~%" desc)
-  (for el in (map (compose format-recurrence-rule
-                           parse-recurrence-rule)
-                  sources)
-       (format #t "=> upprepas ~a.~%" el)))
-
-(define-syntax test
-  (syntax-rules (description source)
-    [(_ (description desc)
-        (source sources ...))
-     (run-test desc (list sources ...))]))
-
-(test
- (description "Daily for 10 occurrences")
- (source "FREQ=DAILY;COUNT=10"))
-;; => "dagligen, 10 gånger."
-
-(test
- (description "Daily until December 24, 1997")
- (source "FREQ=DAILY;UNTIL=19971224T000000Z"))
-;; => "dagligen, till och med den 24 december, 1997 kl.  0:00"
-
-
-(test
- (description "Every other day - forever")
- (source "FREQ=DAILY;INTERVAL=2"))
-;; => "varannan dag"
-
-(test
- (description "Every 10 days, 5 occurrences")
- (source "FREQ=DAILY;INTERVAL=10;COUNT=5"))
-;; => "var tionde dag, 5 gånger."
-
-;; TODO sortera ordningen på dagar
-(test
- (description "Every day in January, for 3 years")
- (source "FREQ=YEARLY;UNTIL=20000131T140000Z;BYMONTH=1;BYDAY=SU,MO,TU,WE,TH,FR,SA"
-         "FREQ=DAILY;UNTIL=20000131T140000Z;BYMONTH=1" ))
-;; => "varje lördag, fredag, torsdag, onsdag, tisdag, måndag & söndag januari varje år, till och med den 31 januari, 2000 kl. 14:00"
-;; => "dagligen, till och med den 31 januari, 2000 kl. 14:00"
-
-(test
- (description "Weekly for 10 occurrences")
- (source "FREQ=WEEKLY;COUNT=10"))
-;; => "varje vecka, 10 gånger."
-
-(test
- (description "Weekly until December 24, 1997")
- (source "FREQ=WEEKLY;UNTIL=19971224T000000Z"))
-;; => "varje vecka, till och med den 24 december, 1997 kl.  0:00"
-
-(test
- (description "Every other week - forever")
- (source "FREQ=WEEKLY;INTERVAL=2;WKST=SU"))
-;; => "varannan vecka"
-
-(test
- (description "Weekly on Tuesday and Thursday for five weeks")
- (source "FREQ=WEEKLY;UNTIL=19971007T000000Z;WKST=SU;BYDAY=TU,TH"
-         "FREQ=WEEKLY;COUNT=10;WKST=SU;BYDAY=TU,TH"))
-;; => "varje tisdag & torsdag, till och med den 07 oktober, 1997 kl. 00:00"
-;; => "varje tisdag & torsdag, 10 gånger."
-
-(test
- (description "Every other week on Monday, Wednesday, and Friday until December 24, 1997, starting on Monday, September 1, 1997:")
- (source "FREQ=WEEKLY;INTERVAL=2;UNTIL=19971224T000000Z;WKST=SU;BYDAY=MO,WE,FR"))
-;; => "varannan måndag, onsdag & fredag, till och med den 24 december, 1997 kl.  0:00"
-
-;; TOOD tittta närmare vad de egentligen vill ha här
-(test
- (description "Every other week on Tuesday and Thursday, for 8 occurrences")
- (source "FREQ=WEEKLY;INTERVAL=2;COUNT=8;WKST=SU;BYDAY=TU,TH"))
-;; => "varannan tisdag & torsdag, 8 gånger."
-
-(test
- (description "Monthly on the first Friday for 10 occurrences")
- (source "FREQ=MONTHLY;COUNT=10;BYDAY=1FR"))
-;; => "första fredagen varje månad, 10 gånger."
-
-(test
- (description "Monthly on the first Friday until December 24, 1997")
- (source "FREQ=MONTHLY;UNTIL=19971224T000000Z;BYDAY=1FR"))
-;; => "förste fredagen varje månad, till och med den 24 december, 1997 kl.  0:00"
-
-(test
- (description "Every other month on the first and last Sunday of the month for 10 occurrences")
- (source "FREQ=MONTHLY;INTERVAL=2;COUNT=10;BYDAY=1SU,-1SU"))
-;; => "första söndagen samt siste söndagen varannan månad, 10 gånger."
-
-(test
- (description "Monthly on the second-to-last Monday of the month for 6 months")
- (source "FREQ=MONTHLY;COUNT=6;BYDAY=-2MO"))
-;; => "näst sista måndagen varje månad, 6 gånger."
-
-(test
- (description "Monthly on the third-to-the-last day of the month, forever")
- (source "FREQ=MONTHLY;BYMONTHDAY=-3"))
-;; => "den tredje sista varje månad"
-
-(test
- (description "Monthly on the 2nd and 15th of the month for 10 occurrences")
- (source "FREQ=MONTHLY;COUNT=10;BYMONTHDAY=2,15"))
-;; => "den andre & femtonde varje månad, 10 gånger."
-
-(test
- (description "Monthly on the first and last day of the month for 10 occurrences")
- (source "FREQ=MONTHLY;COUNT=10;BYMONTHDAY=1,-1"))
-;; => "den förste & sista varje månad, 10 gånger."
-
-(test
- (description "Every 18 months on the 10th thru 15th of the month for 10 occurrences")
- (source "FREQ=MONTHLY;INTERVAL=18;COUNT=10;BYMONTHDAY=10,11,12,13,14,15"))
-;; => "den tionde, elfte, tolfte, trettonde, fjortonde & femtonde var artonde månad, 10 gånger."
-
-(test
- (description "Every Tuesday, every other month")
- (source "FREQ=MONTHLY;INTERVAL=2;BYDAY=TU"))
-;; => "varje tisdag varannan månad"
-
-(test
- (description "Yearly in June and July for 10 occurrences:
+(define (run-test comp)
+  (format #t "~%> ~a~%" (attr comp 'SUMMARY))
+  (format #t "=> upprepas ~a.~%~{~a~^, ~}~%" (format-recurrence-rule
+                                      (attr comp 'RRULE))
+          (map (lambda (d) (datetime->string d "~1 ~3"))
+           (stream->list
+            ;; TODO this assumes a future version of rrule-instances
+            ;; which assumes a pre parsed recurrence rule.
+            10 ((@@ (vcomponent recurrence generate-alt) rrule-instances)
+                comp)))))
+
+
+(define (vevent . rest)
+  (define v (make-vcomponent 'VEVENT))
+
+  (let loop ((rem rest))
+    (unless (null? rem)
+      (let ((symb (-> (car rem)
+                      keyword->string
+                      string-upcase
+                      string->symbol)))
+        (set! (attr v symb)
+          (case symb
+            [(DTSTART EXDATE) (parse-ics-datetime (cadr rem))]
+            [(RRULE) (parse-recurrence-rule (cadr rem))]
+            [else (cadr rem)])))
+      (loop (cddr rem))))
+
+  v)
+
+(map run-test
+ (list
+  (vevent
+   summary: "Daily for 10 occurrences"
+   dtstart: "19970902T090000"
+   rrule: "FREQ=DAILY;COUNT=10")
+  ;; => "dagligen, 10 gånger."
+
+  (vevent
+   summary: "Daily until December 24, 1997"
+   dtstart: "19970902T090000"
+   rrule: "FREQ=DAILY;UNTIL=19971224T000000Z")
+  ;; => "dagligen, till och med den 24 december, 1997 kl.  0:00"
+
+
+  (vevent
+   summary: "Every other day - forever"
+   dtstart: "19970902T090000"
+   rrule: "FREQ=DAILY;INTERVAL=2")
+  ;; => "varannan dag"
+
+  (vevent
+   summary: "Every 10 days, 5 occurrences"
+   dtstart: "19970902T090000"
+   rrule: "FREQ=DAILY;INTERVAL=10;COUNT=5")
+  ;; => "var tionde dag, 5 gånger."
+
+  ;; TODO sortera ordningen på dagar
+  ;; (vevent
+  ;;  summary: "Every day in January, for 3 years"
+  ;;  dtstart: "19980101T090000"
+  ;;  rrule: "FREQ=YEARLY;UNTIL=20000131T140000Z;BYMONTH=1;BYDAY=SU,MO,TU,WE,TH,FR,SA"
+  ;;  "FREQ=DAILY;UNTIL=20000131T140000Z;BYMONTH=1" )
+  ;; => "varje lördag, fredag, torsdag, onsdag, tisdag, måndag & söndag januari varje år, till och med den 31 januari, 2000 kl. 14:00"
+  ;; => "dagligen, till och med den 31 januari, 2000 kl. 14:00"
+
+  (vevent
+   summary: "Weekly for 10 occurrences"
+   dtstart: "19970902T090000"
+   rrule: "FREQ=WEEKLY;COUNT=10")
+  ;; => "varje vecka, 10 gånger."
+
+  (vevent
+   summary: "Weekly until December 24, 1997"
+   dtstart: "19970902T090000"
+   rrule: "FREQ=WEEKLY;UNTIL=19971224T000000Z")
+  ;; => "varje vecka, till och med den 24 december, 1997 kl.  0:00"
+
+  (vevent
+   summary: "Every other week - forever"
+   dtstart: "19970902T090000"
+   rrule: "FREQ=WEEKLY;INTERVAL=2;WKST=SU")
+  ;; => "varannan vecka"
+
+  ;; (vevent
+  ;;  summary: "Weekly on Tuesday and Thursday for five weeks"
+  ;;  dtstart: "19970902T090000"
+  ;;  rrule: "FREQ=WEEKLY;UNTIL=19971007T000000Z;WKST=SU;BYDAY=TU,TH"
+  ;;  "FREQ=WEEKLY;COUNT=10;WKST=SU;BYDAY=TU,TH")
+  ;; => "varje tisdag & torsdag, till och med den 07 oktober, 1997 kl. 00:00"
+  ;; => "varje tisdag & torsdag, 10 gånger."
+
+  (vevent
+   summary: "Every other week on Monday, Wednesday, and Friday until December 24, 1997, starting on Monday, September 1, 1997:"
+   dtstart: "19970901T090000"
+   rrule: "FREQ=WEEKLY;INTERVAL=2;UNTIL=19971224T000000Z;WKST=SU;BYDAY=MO,WE,FR")
+  ;; => "varannan måndag, onsdag & fredag, till och med den 24 december, 1997 kl.  0:00"
+
+  ;; TOOD tittta närmare vad de egentligen vill ha här
+  (vevent
+   summary: "Every other week on Tuesday and Thursday, for 8 occurrences"
+   dtstart: "19970902T090000"
+   rrule: "FREQ=WEEKLY;INTERVAL=2;COUNT=8;WKST=SU;BYDAY=TU,TH")
+  ;; => "varannan tisdag & torsdag, 8 gånger."
+
+  (vevent
+   summary: "Monthly on the first Friday for 10 occurrences"
+   dtstart: "19970905T090000"
+   rrule: "FREQ=MONTHLY;COUNT=10;BYDAY=1FR")
+  ;; => "första fredagen varje månad, 10 gånger."
+
+  (vevent
+   summary: "Monthly on the first Friday until December 24, 1997"
+   dtstart: "19970905T090000"
+   rrule: "FREQ=MONTHLY;UNTIL=19971224T000000Z;BYDAY=1FR")
+  ;; => "förste fredagen varje månad, till och med den 24 december, 1997 kl.  0:00"
+
+  (vevent
+   summary: "Every other month on the first and last Sunday of the month for 10 occurrences"
+   dtstart: "19970907T090000"
+   rrule: "FREQ=MONTHLY;INTERVAL=2;COUNT=10;BYDAY=1SU,-1SU")
+  ;; => "första söndagen samt siste söndagen varannan månad, 10 gånger."
+
+  (vevent
+   summary: "Monthly on the second-to-last Monday of the month for 6 months"
+   dtstart: "19970922T090000"
+   rrule: "FREQ=MONTHLY;COUNT=6;BYDAY=-2MO")
+  ;; => "näst sista måndagen varje månad, 6 gånger."
+
+  (vevent
+   summary: "Monthly on the third-to-the-last day of the month, forever"
+   dtstart: "19970928T090000"
+   rrule: "FREQ=MONTHLY;BYMONTHDAY=-3")
+  ;; => "den tredje sista varje månad"
+
+  (vevent
+   summary: "Monthly on the 2nd and 15th of the month for 10 occurrences"
+   dtstart: "19970902T090000"
+   rrule: "FREQ=MONTHLY;COUNT=10;BYMONTHDAY=2,15")
+  ;; => "den andre & femtonde varje månad, 10 gånger."
+
+  (vevent
+   summary: "Monthly on the first and last day of the month for 10 occurrences"
+   dtstart: "19970930T090000"
+   rrule: "FREQ=MONTHLY;COUNT=10;BYMONTHDAY=1,-1")
+  ;; => "den förste & sista varje månad, 10 gånger."
+
+  (vevent
+   summary: "Every 18 months on the 10th thru 15th of the month for 10 occurrences"
+   dtstart: "19970910T090000"
+   rrule: "FREQ=MONTHLY;INTERVAL=18;COUNT=10;BYMONTHDAY=10,11,12,13,14,15")
+  ;; => "den tionde, elfte, tolfte, trettonde, fjortonde & femtonde var artonde månad, 10 gånger."
+
+  (vevent
+   summary: "Every Tuesday, every other month"
+   dtstart: "19970902T090000"
+   rrule: "FREQ=MONTHLY;INTERVAL=2;BYDAY=TU")
+  ;; => "varje tisdag varannan månad"
+
+  (vevent
+   summary: "Yearly in June and July for 10 occurrences:
 Note: Since none of the BYDAY, BYMONTHDAY, or BYYEARDAY
-components are specified, the day is gotten from \"DTSTART\".")
- (source "FREQ=YEARLY;COUNT=10;BYMONTH=6,7"))
-;; => "juni & juli årligen, 10 gånger."
-
-(test
- (description "Every other year on January, February, and March for 10 occurrences")
- (source "FREQ=YEARLY;INTERVAL=2;COUNT=10;BYMONTH=1,2,3"))
-;; => "januari, februari & mars vartannat år, 10 gånger."
-
-(test
- (description "Every third year on the 1st, 100th, and 200th day for 10 occurrences")
- (source "FREQ=YEARLY;INTERVAL=3;COUNT=10;BYYEARDAY=1,100,200"))
-;; => "dag 1, 100 & 200 vart tredje år, 10 gånger."
-
-(test
- (description "Every 20th Monday of the year, forever")
- (source "FREQ=YEARLY;BYDAY=20MO"))
-;; => "tjugonde måndagen årligen"
-
-(test
- (description "Monday of week number 20 (where the default start of the week is Monday), forever")
- (source "FREQ=YEARLY;BYWEEKNO=20;BYDAY=MO"))
-;; => "varje måndag v.20 årligen"
-
-(test
- (description "Every Thursday in March, forever")
- (source "FREQ=YEARLY;BYMONTH=3;BYDAY=TH"))
-;; => "varje torsdag i mars, årligen"
-
-(test
- (description "Every Thursday, but only during June, July, and August, forever")
- (source "FREQ=YEARLY;BYDAY=TH;BYMONTH=6,7,8"))
-;; => "varje torsdag i juni, juli & augusti, årligen"
-
-;; NOTE This has some weird grammar in swedish
-(test
- (description "Every Friday the 13th, forever")
- (source "FREQ=MONTHLY;BYDAY=FR;BYMONTHDAY=13"))
-;; => "varje fredag den trettonde varje månad"
-
-(test
- (description "The first Saturday that follows the first Sunday of the month,forever")
- (source "FREQ=MONTHLY;BYDAY=SA;BYMONTHDAY=7,8,9,10,11,12,13"))
-;; => "varje lördag den sjunde, åttonde, nionde, tionde, elfte, tolfte & trettonde varje månad"
-
-;; TODO
-(test
- (description
-  "Every 4 years, the first Tuesday after a Monday in November,
-forever (U.S. Presidential Election day)")
- (source "FREQ=YEARLY;INTERVAL=4;BYMONTH=11;BYDAY=TU;BYMONTHDAY=2,3,4,5,6,7,8"))
-;; => "varje tisdag  i novembervart fjärde år"
-;; => "varje tisdag den andre, tredje, fjärde, femte, sjätte, sjunde & åttonde i november vart fjärde år"
-
-;; TODO bysetpos
-
-(test
- (description "The third instance into the month of one of Tuesday, Wednesday, or
-Thursday, for the next 3 months")
- (source "FREQ=MONTHLY;COUNT=3;BYDAY=TU,WE,TH;BYSETPOS=3"))
-
-(test
- (description "The second-to-last weekday of the month")
- (source "FREQ=MONTHLY;BYDAY=MO,TU,WE,TH,FR;BYSETPOS=-2"))
-
-(test
- (description "Every 3 hours from 9:00 AM to 5:00 PM on a specific day")
- (source "FREQ=HOURLY;INTERVAL=3;UNTIL=19970902T170000Z"))
-;; => "var tredje timme, till och med den 02 september, 1997 kl. 17:00"
-
-(test
- (description "Every 15 minutes for 6 occurrences")
- (source "FREQ=MINUTELY;INTERVAL=15;COUNT=6"))
-;; => "var femtonde minut, 6 gånger."
-
-(test
- (description "Every hour and a half for 4 occurrences")
- (source "FREQ=MINUTELY;INTERVAL=90;COUNT=4"))
-;; => "var nitionde minut, 4 gånger."
-
-(test
- (description "Every 20 minutes from 9:00 AM to 4:40 PM every day")
- (source "FREQ=DAILY;BYHOUR=9,10,11,12,13,14,15,16;BYMINUTE=0,20,40"
-         "FREQ=MINUTELY;INTERVAL=20;BYHOUR=9,10,11,12,13,14,15,16"))
-;; => "dagligen kl. 09:00, 09:20, 09:40, 10:00, 10:20, 10:40, 11:00, 11:20, 11:40, 12:00, 12:20, 12:40, 13:00, 13:20, 13:40, 14:00, 14:20, 14:40, 15:00, 15:20, 15:40, 16:00, 16:20 & 16:40"
-;; or
-;; => "var 20e minut kl. 9, 10, 11, 12, 13, 14, 15 & 16"
-
-(test
- (description "An example where the days generated makes a difference because of WKST")
- (source "FREQ=WEEKLY;INTERVAL=2;COUNT=4;BYDAY=TU,SU;WKST=MO"))
-;; => "varannan tisdag & söndag, 4 gånger."
-
-(test
- (description "changing only WKST from MO to SU, yields different results...")
- (source "FREQ=WEEKLY;INTERVAL=2;COUNT=4;BYDAY=TU,SU;WKST=SU"))
-;; => "varannan tisdag & söndag, 4 gånger."
-
-(test
- (description "An example where an invalid date (i.e., February 30) is ignored.")
- (source "FREQ=MONTHLY;BYMONTHDAY=15,30;COUNT=5"))
-;; => "den 15 & 30 varje månad, 5 gånger."
+components are specified, the day is gotten from \"DTSTART\"."
+   dtstart: "19970610T090000"
+   rrule: "FREQ=YEARLY;COUNT=10;BYMONTH=6,7")
+  ;; => "juni & juli årligen, 10 gånger."
+
+  (vevent
+   summary: "Every other year on January, February, and March for 10 occurrences"
+   dtstart: "19970310T090000"
+   rrule: "FREQ=YEARLY;INTERVAL=2;COUNT=10;BYMONTH=1,2,3")
+  ;; => "januari, februari & mars vartannat år, 10 gånger."
+
+  (vevent
+   summary: "Every third year on the 1st, 100th, and 200th day for 10 occurrences"
+   dtstart: "19970101T090000"
+   rrule: "FREQ=YEARLY;INTERVAL=3;COUNT=10;BYYEARDAY=1,100,200")
+  ;; => "dag 1, 100 & 200 vart tredje år, 10 gånger."
+
+  (vevent
+   summary: "Every 20th Monday of the year, forever"
+   dtstart: "19970519T090000"
+   rrule: "FREQ=YEARLY;BYDAY=20MO")
+  ;; => "tjugonde måndagen årligen"
+
+  (vevent
+   summary: "Monday of week number 20 (where the default start of the week is Monday), forever"
+   dtstart: "19970512T090000"
+   rrule: "FREQ=YEARLY;BYWEEKNO=20;BYDAY=MO")
+  ;; => "varje måndag v.20 årligen"
+
+  (vevent
+   summary: "Every Thursday in March, forever"
+   dtstart: "19970313T090000"
+   rrule: "FREQ=YEARLY;BYMONTH=3;BYDAY=TH")
+  ;; => "varje torsdag i mars, årligen"
+
+  (vevent
+   summary: "Every Thursday, but only during June, July, and August, forever"
+   dtstart: "19970605T090000"
+   rrule: "FREQ=YEARLY;BYDAY=TH;BYMONTH=6,7,8")
+  ;; => "varje torsdag i juni, juli & augusti, årligen"
+
+  ;; NOTE This has some weird grammar in swedish
+  (vevent
+   summary: "Every Friday the 13th, forever"
+   dtstart: "19970902T090000"
+   exdate: "19970902T090000"
+   rrule: "FREQ=MONTHLY;BYDAY=FR;BYMONTHDAY=13")
+  ;; => "varje fredag den trettonde varje månad"
+
+  (vevent
+   summary: "The first Saturday that follows the first Sunday of the month,forever"
+   dtstart: "19970913T090000"
+   rrule: "FREQ=MONTHLY;BYDAY=SA;BYMONTHDAY=7,8,9,10,11,12,13")
+  ;; => "varje lördag den sjunde, åttonde, nionde, tionde, elfte, tolfte & trettonde varje månad"
+
+  ;; TODO
+  (vevent
+   summary:
+   "Every 4 years, the first Tuesday after a Monday in November,
+forever (U.S. Presidential Election day)"
+   dtstart: "19961105T090000"
+   rrule: "FREQ=YEARLY;INTERVAL=4;BYMONTH=11;BYDAY=TU;BYMONTHDAY=2,3,4,5,6,7,8")
+  ;; => "varje tisdag  i novembervart fjärde år"
+  ;; => "varje tisdag den andre, tredje, fjärde, femte, sjätte, sjunde & åttonde i november vart fjärde år"
+
+  ;; TODO bysetpos
+
+  (vevent
+   summary: "The third instance into the month of one of Tuesday, Wednesday, or
+Thursday, for the next 3 months"
+   dtstart: "19970904T090000"
+   rrule: "FREQ=MONTHLY;COUNT=3;BYDAY=TU,WE,TH;BYSETPOS=3")
+
+  (vevent
+   summary: "The second-to-last weekday of the month"
+   dtstart: "19970929T090000"
+   rrule: "FREQ=MONTHLY;BYDAY=MO,TU,WE,TH,FR;BYSETPOS=-2")
+
+  (vevent
+   summary: "Every 3 hours from 9:00 AM to 5:00 PM on a specific day"
+   dtstart: "19970902T090000"
+   rrule: "FREQ=HOURLY;INTERVAL=3;UNTIL=19970902T170000Z")
+  ;; => "var tredje timme, till och med den 02 september, 1997 kl. 17:00"
+
+  (vevent
+   summary: "Every 15 minutes for 6 occurrences"
+   dtstart: "19970902T090000"
+   rrule: "FREQ=MINUTELY;INTERVAL=15;COUNT=6")
+  ;; => "var femtonde minut, 6 gånger."
+
+  (vevent
+   summary: "Every hour and a half for 4 occurrences"
+   dtstart: "19970902T090000"
+   rrule: "FREQ=MINUTELY;INTERVAL=90;COUNT=4")
+  ;; => "var nitionde minut, 4 gånger."
+
+  ;; (vevent
+  ;;  summary: "Every 20 minutes from 9:00 AM to 4:40 PM every day"
+  ;;  dtstart: "19970902T090000"
+  ;;  rrule: "FREQ=DAILY;BYHOUR=9,10,11,12,13,14,15,16;BYMINUTE=0,20,40"
+  ;;  "FREQ=MINUTELY;INTERVAL=20;BYHOUR=9,10,11,12,13,14,15,16")
+  ;; ;; => "dagligen kl. 09:00, 09:20, 09:40, 10:00, 10:20, 10:40, 11:00, 11:20, 11:40, 12:00, 12:20, 12:40, 13:00, 13:20, 13:40, 14:00, 14:20, 14:40, 15:00, 15:20, 15:40, 16:00, 16:20 & 16:40"
+  ;; ;; or
+  ;; ;; => "var 20e minut kl. 9, 10, 11, 12, 13, 14, 15 & 16"
+
+  (vevent
+   summary: "An example where the days generated makes a difference because of WKST"
+   dtstart: "19970805T090000"
+   rrule: "FREQ=WEEKLY;INTERVAL=2;COUNT=4;BYDAY=TU,SU;WKST=MO")
+  ;; => "varannan tisdag & söndag, 4 gånger."
+
+  (vevent
+   summary: "changing only WKST from MO to SU, yields different results..."
+   dtstart: "19970805T090000"
+   rrule: "FREQ=WEEKLY;INTERVAL=2;COUNT=4;BYDAY=TU,SU;WKST=SU")
+  ;; => "varannan tisdag & söndag, 4 gånger."
+
+  (vevent
+   summary: "An example where an invalid date (i.e., February 30) is ignored."
+   dtstart: "20070115T090000"
+   rrule: "FREQ=MONTHLY;BYMONTHDAY=15,30;COUNT=5")
+  ;; => "den 15 & 30 varje månad, 5 gånger."
+  ))