Repair BYDAY output for ical serialization.

I have no idea why the byday case was commented out while implementing
xcal output. Either way it's now fixed, and should hopefully stay fixed
with some tests.

2 files changed, 78 insertions, 2 deletions

diff --git a/module/vcomponent/recurrence/internal.scm b/module/vcomponent/recurrence/internal.scm
index 1b9dd405..a57dfd65 100644
--- a/module/vcomponent/recurrence/internal.scm
+++ b/module/vcomponent/recurrence/internal.scm
@@ -92,8 +92,8 @@
      (string-upcase
       (week-day-name value 2
                      locale: (make-locale (list LC_TIME) "C")))]
-    ;; [(byday)
-    ;;  (string-join (map byday->string value) ",")]
+    [(byday)
+     (string-join (map byday->string value) ",")]
     [(freq count interval)
      (format #f "~a" value)]
     [(until)
diff --git a/tests/rrule-serialization.scm b/tests/rrule-serialization.scm
new file mode 100644
index 00000000..53365661
--- /dev/null
+++ b/tests/rrule-serialization.scm
@@ -0,0 +1,76 @@
+(
+ ;; Yes, this is ugly. But how else would I test a private procedure?
+ ((guile) @@)
+
+ ((vcomponent recurrence internal)
+  recur-rule->rrule-string
+  recur-rule->rrule-sxml
+  byday
+  )
+
+ ((vcomponent recurrence parse) parse-recurrence-rule)
+
+ ((ice-9 peg)
+  keyword-flatten
+  )
+ )
+
+
+(test-equal
+    "Parse of week day"
+    '(#f . 3)
+  ((@@ (vcomponent recurrence parse) parse-day-spec) "WE"))
+
+(test-equal
+    "Parse of week day with positive offset"
+    '(1 . 3)
+  ((@@ (vcomponent recurrence parse) parse-day-spec) "1WE"))
+
+(test-equal
+    "Parse of week day with positive offset (and plus)"
+    '(2 . 3)
+  ((@@ (vcomponent recurrence parse) parse-day-spec) "+2WE"))
+
+(test-equal
+    "Parse of week day with negative offset"
+    '(-3 . 3)
+  ((@@ (vcomponent recurrence parse) parse-day-spec) "-3WE"))
+
+
+;; numeric prefixes in the BYDAY list is only valid when
+;; FREQ={MONTHLY,YEARLY}, but that should be handled in a
+;; later stage since we are just testing the parser here.
+;; (p. 41)
+
+
+(define field->string
+  (@@ (vcomponent recurrence internal) field->string))
+
+
+(let ((rule (parse-recurrence-rule "BYDAY=MO,TU,WE")))
+  (test-equal "Direct return of parsed value"
+    "MO,TU,WE"
+    (field->string 'byday (byday rule)))
+
+  (test-equal "Direct return, but as SXML"
+    '((byday "MO")
+      (byday "TU")
+      (byday "WE"))
+    (filter (lambda (pair)
+              (eq? 'byday (car pair)))
+            (keyword-flatten '(interval byday wkst)
+                             (recur-rule->rrule-sxml rule)))))
+
+(let ((rule (parse-recurrence-rule "BYDAY=+1MO,1TU,-2FR")))
+  (test-equal "Direct return of parsed value"
+    "1MO,1TU,-2FR"
+    (field->string 'byday (byday rule)))
+
+ (test-equal "Direct return, but as SXML"
+   '((byday "1MO")
+     (byday "1TU")
+     (byday "-2FR"))
+   (filter (lambda (pair)
+             (eq? 'byday (car pair)))
+           (keyword-flatten '(interval byday wkst)
+                            (recur-rule->rrule-sxml rule)))))