allenporter · ChrisCarini · Oct 19, 2025
diff --git a/tests/compat/__snapshots__/test_make_compat.ambr b/tests/compat/__snapshots__/test_make_compat.ambr
@@ -150,6 +150,157 @@
   END:VCALENDAR
   '''
 # ---
+# name: test_make_compat[office_365_compat_roundtrip_pst_fails]
+  '''
+  BEGIN:VCALENDAR
+  METHOD:PUBLISH
+  PRODID:Microsoft Exchange Server 2010
+  VERSION:2.0
+  BEGIN:VEVENT
+  DTSTAMP:20251019T013024Z
+  UID:040000008200E00074C5B7101A82E00800000000687C546B5596DA01000000000000000
+   010000000309AE93C8C3A94489F90ADBEA30C2F2B
+  DTSTART;TZID=PST:20241018T000000
+  DTEND;TZID=PST:20241018T070000
+  SUMMARY:Private Appointment
+  CLASS:PRIVATE
+  PRIORITY:5
+  RECURRENCE-ID:20241018T000000
+  STATUS:CONFIRMED
+  TRANSP:OPAQUE
+  END:VEVENT
+  BEGIN:VTIMEZONE
+  TZID:Pacific Standard Time
+  BEGIN:STANDARD
+  DTSTART:16010101T020000
+  TZOFFSETTO:-0800
+  TZOFFSETFROM:-0700
+  RRULE:FREQ=YEARLY;BYDAY=1SU;BYMONTH=11
+  END:STANDARD
+  BEGIN:DAYLIGHT
+  DTSTART:16010101T020000
+  TZOFFSETTO:-0700
+  TZOFFSETFROM:-0800
+  RRULE:FREQ=YEARLY;BYDAY=2SU;BYMONTH=3
+  END:DAYLIGHT
+  END:VTIMEZONE
+  BEGIN:VTIMEZONE
+  TZID:Eastern Standard Time
+  BEGIN:STANDARD
+  DTSTART:16010101T020000
+  TZOFFSETTO:-0500
+  TZOFFSETFROM:-0400
+  RRULE:FREQ=YEARLY;BYDAY=1SU;BYMONTH=11
+  END:STANDARD
+  BEGIN:DAYLIGHT
+  DTSTART:16010101T020000
+  TZOFFSETTO:-0400
+  TZOFFSETFROM:-0500
+  RRULE:FREQ=YEARLY;BYDAY=2SU;BYMONTH=3
+  END:DAYLIGHT
+  END:VTIMEZONE
+  BEGIN:VTIMEZONE
+  TZID:Mountain Standard Time
+  BEGIN:STANDARD
+  DTSTART:16010101T020000
+  TZOFFSETTO:-0700
+  TZOFFSETFROM:-0600
+  RRULE:FREQ=YEARLY;BYDAY=1SU;BYMONTH=11
+  END:STANDARD
+  BEGIN:DAYLIGHT
+  DTSTART:16010101T020000
+  TZOFFSETTO:-0600
+  TZOFFSETFROM:-0700
+  RRULE:FREQ=YEARLY;BYDAY=2SU;BYMONTH=3
+  END:DAYLIGHT
+  END:VTIMEZONE
+  BEGIN:VTIMEZONE
+  TZID:Romance Standard Time
+  BEGIN:STANDARD
+  DTSTART:16010101T030000
+  TZOFFSETTO:+0100
+  TZOFFSETFROM:+0200
+  RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=10
+  END:STANDARD
+  BEGIN:DAYLIGHT
+  DTSTART:16010101T020000
+  TZOFFSETTO:+0200
+  TZOFFSETFROM:+0100
+  RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=3
+  END:DAYLIGHT
+  END:VTIMEZONE
+  BEGIN:VTIMEZONE
+  TZID:UTC
+  BEGIN:STANDARD
+  DTSTART:16010101T000000
+  TZOFFSETTO:+0000
+  TZOFFSETFROM:+0000
+  END:STANDARD
+  BEGIN:DAYLIGHT
+  DTSTART:16010101T000000
+  TZOFFSETTO:+0000
+  TZOFFSETFROM:+0000
+  END:DAYLIGHT
+  END:VTIMEZONE
+  BEGIN:VTIMEZONE
+  TZID:Central Standard Time
+  BEGIN:STANDARD
+  DTSTART:16010101T020000
+  TZOFFSETTO:-0600
+  TZOFFSETFROM:-0500
+  RRULE:FREQ=YEARLY;BYDAY=1SU;BYMONTH=11
+  END:STANDARD
+  BEGIN:DAYLIGHT
+  DTSTART:16010101T020000
+  TZOFFSETTO:-0500
+  TZOFFSETFROM:-0600
+  RRULE:FREQ=YEARLY;BYDAY=2SU;BYMONTH=3
+  END:DAYLIGHT
+  END:VTIMEZONE
+  BEGIN:VTIMEZONE
+  TZID:GMT Standard Time
+  BEGIN:STANDARD
+  DTSTART:16010101T020000
+  TZOFFSETTO:+0000
+  TZOFFSETFROM:+0100
+  RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=10
+  END:STANDARD
+  BEGIN:DAYLIGHT
+  DTSTART:16010101T010000
+  TZOFFSETTO:+0100
+  TZOFFSETFROM:+0000
+  RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=3
+  END:DAYLIGHT
+  END:VTIMEZONE
+  BEGIN:VTIMEZONE
+  TZID:India Standard Time
+  BEGIN:STANDARD
+  DTSTART:16010101T000000
+  TZOFFSETTO:+0530
+  TZOFFSETFROM:+0530
+  END:STANDARD
+  BEGIN:DAYLIGHT
+  DTSTART:16010101T000000
+  TZOFFSETTO:+0530
+  TZOFFSETFROM:+0530
+  END:DAYLIGHT
+  END:VTIMEZONE
+  BEGIN:VTIMEZONE
+  TZID:US Mountain Standard Time
+  BEGIN:STANDARD
+  DTSTART:16010101T000000
+  TZOFFSETTO:-0700
+  TZOFFSETFROM:-0700
+  END:STANDARD
+  BEGIN:DAYLIGHT
+  DTSTART:16010101T000000
+  TZOFFSETTO:-0700
+  TZOFFSETFROM:-0700
+  END:DAYLIGHT
+  END:VTIMEZONE
+  END:VCALENDAR
+  '''
+# ---
 # name: test_make_compat[office_365_extended_timezone]
   '''
   BEGIN:VCALENDAR

diff --git a/tests/compat/testdata/office_365_compat_roundtrip_pst_fails.ics b/tests/compat/testdata/office_365_compat_roundtrip_pst_fails.ics
@@ -0,0 +1,157 @@
+BEGIN:VCALENDAR
+METHOD:PUBLISH
+PRODID:Microsoft Exchange Server 2010
+VERSION:2.0
+X-WR-CALNAME:Calendar
+BEGIN:VTIMEZONE
+TZID:Pacific Standard Time
+BEGIN:STANDARD
+DTSTART:16010101T020000
+TZOFFSETFROM:-0700
+TZOFFSETTO:-0800
+RRULE:FREQ=YEARLY;INTERVAL=1;BYDAY=1SU;BYMONTH=11
+END:STANDARD
+BEGIN:DAYLIGHT
+DTSTART:16010101T020000
+TZOFFSETFROM:-0800
+TZOFFSETTO:-0700
+RRULE:FREQ=YEARLY;INTERVAL=1;BYDAY=2SU;BYMONTH=3
+END:DAYLIGHT
+END:VTIMEZONE
+BEGIN:VTIMEZONE
+TZID:Eastern Standard Time
+BEGIN:STANDARD
+DTSTART:16010101T020000
+TZOFFSETFROM:-0400
+TZOFFSETTO:-0500
+RRULE:FREQ=YEARLY;INTERVAL=1;BYDAY=1SU;BYMONTH=11
+END:STANDARD
+BEGIN:DAYLIGHT
+DTSTART:16010101T020000
+TZOFFSETFROM:-0500
+TZOFFSETTO:-0400
+RRULE:FREQ=YEARLY;INTERVAL=1;BYDAY=2SU;BYMONTH=3
+END:DAYLIGHT
+END:VTIMEZONE
+BEGIN:VTIMEZONE
+TZID:Mountain Standard Time
+BEGIN:STANDARD
+DTSTART:16010101T020000
+TZOFFSETFROM:-0600
+TZOFFSETTO:-0700
+RRULE:FREQ=YEARLY;INTERVAL=1;BYDAY=1SU;BYMONTH=11
+END:STANDARD
+BEGIN:DAYLIGHT
+DTSTART:16010101T020000
+TZOFFSETFROM:-0700
+TZOFFSETTO:-0600
+RRULE:FREQ=YEARLY;INTERVAL=1;BYDAY=2SU;BYMONTH=3
+END:DAYLIGHT
+END:VTIMEZONE
+BEGIN:VTIMEZONE
+TZID:Romance Standard Time
+BEGIN:STANDARD
+DTSTART:16010101T030000
+TZOFFSETFROM:+0200
+TZOFFSETTO:+0100
+RRULE:FREQ=YEARLY;INTERVAL=1;BYDAY=-1SU;BYMONTH=10
+END:STANDARD
+BEGIN:DAYLIGHT
+DTSTART:16010101T020000
+TZOFFSETFROM:+0100
+TZOFFSETTO:+0200
+RRULE:FREQ=YEARLY;INTERVAL=1;BYDAY=-1SU;BYMONTH=3
+END:DAYLIGHT
+END:VTIMEZONE
+BEGIN:VTIMEZONE
+TZID:UTC
+BEGIN:STANDARD
+DTSTART:16010101T000000
+TZOFFSETFROM:+0000
+TZOFFSETTO:+0000
+END:STANDARD
+BEGIN:DAYLIGHT
+DTSTART:16010101T000000
+TZOFFSETFROM:+0000
+TZOFFSETTO:+0000
+END:DAYLIGHT
+END:VTIMEZONE
+BEGIN:VTIMEZONE
+TZID:Central Standard Time
+BEGIN:STANDARD
+DTSTART:16010101T020000
+TZOFFSETFROM:-0500
+TZOFFSETTO:-0600
+RRULE:FREQ=YEARLY;INTERVAL=1;BYDAY=1SU;BYMONTH=11
+END:STANDARD
+BEGIN:DAYLIGHT
+DTSTART:16010101T020000
+TZOFFSETFROM:-0600
+TZOFFSETTO:-0500
+RRULE:FREQ=YEARLY;INTERVAL=1;BYDAY=2SU;BYMONTH=3
+END:DAYLIGHT
+END:VTIMEZONE
+BEGIN:VTIMEZONE
+TZID:GMT Standard Time
+BEGIN:STANDARD
+DTSTART:16010101T020000
+TZOFFSETFROM:+0100
+TZOFFSETTO:+0000
+RRULE:FREQ=YEARLY;INTERVAL=1;BYDAY=-1SU;BYMONTH=10
+END:STANDARD
+BEGIN:DAYLIGHT
+DTSTART:16010101T010000
+TZOFFSETFROM:+0000
+TZOFFSETTO:+0100
+RRULE:FREQ=YEARLY;INTERVAL=1;BYDAY=-1SU;BYMONTH=3
+END:DAYLIGHT
+END:VTIMEZONE
+BEGIN:VTIMEZONE
+TZID:India Standard Time
+BEGIN:STANDARD
+DTSTART:16010101T000000
+TZOFFSETFROM:+0530
+TZOFFSETTO:+0530
+END:STANDARD
+BEGIN:DAYLIGHT
+DTSTART:16010101T000000
+TZOFFSETFROM:+0530
+TZOFFSETTO:+0530
+END:DAYLIGHT
+END:VTIMEZONE
+BEGIN:VTIMEZONE
+TZID:US Mountain Standard Time
+BEGIN:STANDARD
+DTSTART:16010101T000000
+TZOFFSETFROM:-0700
+TZOFFSETTO:-0700
+END:STANDARD
+BEGIN:DAYLIGHT
+DTSTART:16010101T000000
+TZOFFSETFROM:-0700
+TZOFFSETTO:-0700
+END:DAYLIGHT
+END:VTIMEZONE
+BEGIN:VEVENT
+UID:040000008200E00074C5B7101A82E00800000000687C546B5596DA01000000000000000
+ 010000000309AE93C8C3A94489F90ADBEA30C2F2B
+RECURRENCE-ID;TZID=Pacific Standard Time:20241018T000000
+SUMMARY:Private Appointment
+DTSTART;TZID=Pacific Standard Time:20241018T000000
+DTEND;TZID=Pacific Standard Time:20241018T070000
+CLASS:PRIVATE
+PRIORITY:5
+DTSTAMP:20251019T013024Z
+TRANSP:OPAQUE
+STATUS:CONFIRMED
+X-MICROSOFT-CDO-BUSYSTATUS:OOF
+X-MICROSOFT-CDO-INTENDEDSTATUS:BUSY
+X-MICROSOFT-CDO-ALLDAYEVENT:FALSE
+X-MICROSOFT-CDO-IMPORTANCE:1
+X-MICROSOFT-CDO-INSTTYPE:0
+X-MICROSOFT-DONOTFORWARDMEETING:FALSE
+X-MICROSOFT-DISALLOW-COUNTER:FALSE
+X-MICROSOFT-REQUESTEDATTENDANCEMODE:DEFAULT
+X-MICROSOFT-ISRESPONSEREQUESTED:FALSE
+END:VEVENT
+END:VCALENDAR