fix(caldav): expand RRULE for recurring events

internal/caldav/ics_shared_test.go

@@ -49,6 +49,23 @@ func mustCalEvent(t *testing.T, raw string) ical.Event {
 	return evs[0]
 }
 
+// icssubSeriesID returns the stable ID the CalDAV backend advertises for the
+// (single) series in raw. All tests here use single-series feeds, so this is
+// just GroupSeries(raw)[0].ID().
+func icssubSeriesID(t *testing.T, raw string) string {
+	t.Helper()
+	_ = t
+	cal, err := ical.NewDecoder(strings.NewReader(raw)).Decode()
+	if err != nil {
+		panic("icssubSeriesID: " + err.Error())
+	}
+	series := icssub.GroupSeries(cal)
+	if len(series) == 0 {
+		panic("icssubSeriesID: no series")
+	}
+	return series[0].ID()
+}
+
 // TestICSSubscriptionListAndGetObject verifies the full CalDAV read path
 // for an ICS subscription: ListCalendarObjects returns one synthetic
 // stand-alone object whose Path is derived from icssub.EventID (not from
@@ -92,16 +109,12 @@ func TestICSSubscriptionListAndGetObject(t *testing.T) {
 		t.Fatalf("expected 1 object, got %d", len(objs))
 	}
 
-	// The Path must be derived from the event's DTSTART/DTEND/SUMMARY —
-	// i.e. icssub.EventID(ev), not from the event's position in the feed.
-	ev := mustCalEvent(t, icsSample)
-	wantID := icssub.EventID(ev)
-	if wantID == "" {
-		t.Fatal("EventID must be non-empty for a valid event")
-	}
+	// The Path must be derived from the event's stable identity (its UID) —
+	// i.e. the series ID — not from the event's position in the feed.
+	wantID := icssubSeriesID(t, icsSample)
 	wantPath := calObjectPath("holidays", wantID)
 	if objs[0].Path != wantPath {
-		t.Fatalf("Path = %q, want %q (icssub.EventID-based, not position-based)", objs[0].Path, wantPath)
+		t.Fatalf("Path = %q, want %q (series-ID-based, not position-based)", objs[0].Path, wantPath)
 	}
 
 	// GetCalendarObject by the same Path should return an object that has
@@ -260,7 +273,7 @@ func TestICSSubscriptionEventIDMatchesEventInCalDav(t *testing.T) {
 		t.Fatalf("list: objs=%d err=%v", len(objs), err)
 	}
 	gotPath := objs[0].Path
-	wantID := icssub.EventID(mustCalEvent(t, icsSample))
+	wantID := icssubSeriesID(t, icsSample)
 	wantPath := calObjectPath("holidays", wantID)
 	if gotPath != wantPath {
 		t.Fatalf("CalDAV object path %q does not match web-side EventID-derived %q", gotPath, wantPath)