Harden CalDAV write-back with retries (#1193)

Co-authored-by: Alexandre Teixeira <111787685+alteixeira20@users.noreply.github.com>

tests/test_caldav_writeback.py

@@ -22,7 +22,9 @@ CAL_ID = _stable_cal_id(REMOTE_URL)
 
 
 class FakeEvent:
-    def __init__(self):
+    def __init__(self, url="https://p69-caldav.icloud.com/123/calendars/home/evt-1.ics"):
+        self.url = url
+        self.etag = '"abc123"'
         self.data = "OLD"
         self.saved = False
         self.deleted = False
@@ -39,6 +41,7 @@ class FakeCalendar:
         self.url = url
         self._existing = existing
         self.saved_ical = None
+        self.created = FakeEvent(str(url).rstrip("/") + "/created.ics")
 
     def event_by_uid(self, uid):
         if self._existing is None:
@@ -47,6 +50,7 @@ class FakeCalendar:
 
     def save_event(self, ical):
         self.saved_ical = ical
+        return self.created
 
 
 def _ev(**over):
@@ -91,6 +95,8 @@ def test_push_create_calls_save_event():
     res = push_event([cal], CAL_ID, _ev(), delete=False)
     assert res["ok"] and res.get("created")
     assert cal.saved_ical and "UID:evt-1" in cal.saved_ical
+    assert res["calendar_url"] == REMOTE_URL
+    assert res["remote_href"].endswith("/created.ics")
 
 
 def test_push_update_overwrites_existing():
@@ -100,6 +106,8 @@ def test_push_update_overwrites_existing():
     assert res["ok"] and res.get("updated")
     assert existing.saved and "SUMMARY:Moved" in existing.data
     assert cal.saved_ical is None  # used update path, not create
+    assert res["remote_href"].endswith("evt-1.ics")
+    assert res["remote_etag"] == '"abc123"'
 
 
 def test_push_delete_removes_existing():