test items having tzinfo only on dtstart or dtend set for whatever reason

radicale/tests/static/event_issue1847_1.ics

@@ -0,0 +1,14 @@
+BEGIN:VCALENDAR
+VERSION:2.0
+PRODID:-//algoo.fr//NONSGML Open Calendar v0.9//EN
+BEGIN:VEVENT
+CREATED:20250814T153429Z
+LAST-MODIFIED:20250814T153503Z
+DTSTAMP:20250814T153503Z
+UID:f91964cb-53ca-4942-8811-c38f076f4328
+SUMMARY:error
+DTSTART:20250814T180000
+DTEND;TZID=Europe/Brussels:20250814T190000
+TRANSP:OPAQUE
+END:VEVENT
+END:VCALENDAR

radicale/tests/static/event_issue1847_2.ics

@@ -0,0 +1,14 @@
+BEGIN:VCALENDAR
+VERSION:2.0
+PRODID:-//algoo.fr//NONSGML Open Calendar v0.9//EN
+BEGIN:VEVENT
+CREATED:20250814T153429Z
+LAST-MODIFIED:20250814T153503Z
+DTSTAMP:20250814T153503Z
+UID:f91964cb-53ca-4942-8811-c38f076f4328
+SUMMARY:error
+DTSTART;TZID=Europe/Brussels:20250814T180000
+DTEND:20250814T190000
+TRANSP:OPAQUE
+END:VEVENT
+END:VCALENDAR