From 09cfcfd6826f9bc8b379dde88e1d9ca719c1bdb2 Mon Sep 17 00:00:00 2001
From: Craig Jennings <c@cjennings.net>
Date: Tue, 3 Feb 2026 08:09:30 -0600
Subject: feat(calendar-sync): add EXDATE support for excluded recurring event
 dates

When someone deletes a single instance of a recurring meeting in Google
Calendar, the calendar exports an EXDATE property marking that date as
excluded. Previously, calendar-sync expanded the RRULE without filtering
out these excluded dates, causing deleted instances to appear in org output.

New functions:
- calendar-sync--get-exdates: Extract all EXDATE values from event
- calendar-sync--get-exdate-line: Get full EXDATE line with parameters
- calendar-sync--parse-exdate: Parse EXDATE into datetime list
- calendar-sync--collect-exdates: Collect excluded dates with TZ conversion
- calendar-sync--exdate-matches-p: Check if occurrence matches an EXDATE
- calendar-sync--filter-exdates: Filter out excluded dates from occurrences

Modified calendar-sync--expand-recurring-event to collect and filter
EXDATEs after RRULE expansion.

Includes 47 new tests covering extraction, parsing, collection, filtering,
and integration with RECURRENCE-ID exceptions.
---
 tests/test-calendar-sync--parse-exdate.el | 80 +++++++++++++++++++++++++++++++
 1 file changed, 80 insertions(+)
 create mode 100644 tests/test-calendar-sync--parse-exdate.el

(limited to 'tests/test-calendar-sync--parse-exdate.el')

diff --git a/tests/test-calendar-sync--parse-exdate.el b/tests/test-calendar-sync--parse-exdate.el
new file mode 100644
index 00000000..2be3d3a1
--- /dev/null
+++ b/tests/test-calendar-sync--parse-exdate.el
@@ -0,0 +1,80 @@
+;;; test-calendar-sync--parse-exdate.el --- Tests for EXDATE parsing  -*- lexical-binding: t; -*-
+
+;;; Commentary:
+;; Unit tests for calendar-sync--parse-exdate function.
+;; Tests parsing EXDATE values into (year month day hour minute) lists.
+;; Following quality-engineer.org guidelines: one function per file.
+
+;;; Code:
+
+(require 'ert)
+(add-to-list 'load-path (expand-file-name "." (file-name-directory load-file-name)))
+(add-to-list 'load-path (expand-file-name "../modules" (file-name-directory load-file-name)))
+(require 'testutil-calendar-sync)
+(require 'calendar-sync)
+
+;;; Normal Cases
+
+(ert-deftest test-calendar-sync--parse-exdate-normal-datetime-returns-list ()
+  "Test parsing standard datetime format returns correct list."
+  (let ((result (calendar-sync--parse-exdate "20260203T130000")))
+    (should (equal '(2026 2 3 13 0) result))))
+
+(ert-deftest test-calendar-sync--parse-exdate-normal-with-z-returns-list ()
+  "Test parsing UTC datetime with Z suffix returns correct list."
+  (let ((result (calendar-sync--parse-exdate "20260203T180000Z")))
+    (should (equal '(2026 2 3 18 0) result))))
+
+(ert-deftest test-calendar-sync--parse-exdate-normal-date-only-returns-list ()
+  "Test parsing date-only format returns list with nil for time."
+  (let ((result (calendar-sync--parse-exdate "20260203")))
+    (should (equal '(2026 2 3 nil nil) result))))
+
+(ert-deftest test-calendar-sync--parse-exdate-normal-with-seconds-returns-list ()
+  "Test parsing datetime ignores seconds."
+  (let ((result (calendar-sync--parse-exdate "20260203T130045")))
+    (should (equal '(2026 2 3 13 0) result))))
+
+;;; Boundary Cases
+
+(ert-deftest test-calendar-sync--parse-exdate-boundary-midnight-returns-zero-hour ()
+  "Test parsing midnight time returns hour=0."
+  (let ((result (calendar-sync--parse-exdate "20260203T000000")))
+    (should (equal '(2026 2 3 0 0) result))))
+
+(ert-deftest test-calendar-sync--parse-exdate-boundary-end-of-day-returns-23 ()
+  "Test parsing end-of-day time returns hour=23."
+  (let ((result (calendar-sync--parse-exdate "20260203T235900")))
+    (should (equal '(2026 2 3 23 59) result))))
+
+(ert-deftest test-calendar-sync--parse-exdate-boundary-leap-year-feb29-returns-correct ()
+  "Test parsing Feb 29 on leap year."
+  (let ((result (calendar-sync--parse-exdate "20280229T120000")))
+    (should (equal '(2028 2 29 12 0) result))))
+
+(ert-deftest test-calendar-sync--parse-exdate-boundary-new-years-eve-returns-correct ()
+  "Test parsing Dec 31."
+  (let ((result (calendar-sync--parse-exdate "20261231T235900")))
+    (should (equal '(2026 12 31 23 59) result))))
+
+(ert-deftest test-calendar-sync--parse-exdate-boundary-jan-1-returns-correct ()
+  "Test parsing Jan 1."
+  (let ((result (calendar-sync--parse-exdate "20260101T000000")))
+    (should (equal '(2026 1 1 0 0) result))))
+
+;;; Error Cases
+
+(ert-deftest test-calendar-sync--parse-exdate-error-empty-returns-nil ()
+  "Test that empty string returns nil."
+  (should (null (calendar-sync--parse-exdate ""))))
+
+(ert-deftest test-calendar-sync--parse-exdate-error-nil-returns-nil ()
+  "Test that nil input returns nil."
+  (should (null (calendar-sync--parse-exdate nil))))
+
+(ert-deftest test-calendar-sync--parse-exdate-error-invalid-format-returns-nil ()
+  "Test that invalid format returns nil."
+  (should (null (calendar-sync--parse-exdate "not-a-date"))))
+
+(provide 'test-calendar-sync--parse-exdate)
+;;; test-calendar-sync--parse-exdate.el ends here
-- 
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