diff --git a/app/test_goldens/calendrical_events/page/past_calendrical_events_page_test.dart b/app/test_goldens/calendrical_events/page/past_calendrical_events_page_test.dart
index bdfe013f8..ba2048341 100644
--- a/app/test_goldens/calendrical_events/page/past_calendrical_events_page_test.dart
+++ b/app/test_goldens/calendrical_events/page/past_calendrical_events_page_test.dart
@@ -104,11 +104,15 @@ void main() {
 
     group('without Sharezone Plus', () {
       setUp(() {
-        when(controller.state).thenReturn(
-          const PastCalendricalEventsPageNotUnlockedState(
-            sortingOrder: EventsSortingOrder.descending,
-          ),
+        const state = PastCalendricalEventsPageNotUnlockedState(
+          sortingOrder: EventsSortingOrder.descending,
         );
+        // Mockito does not support mocking sealed classes yet, so we have to
+        // provide a dummy implementation of the state.
+        //
+        // Ticket: https://github.com/dart-lang/mockito/issues/675
+        provideDummy<PastCalendricalEventsPageState>(state);
+        when(controller.state).thenReturn(state);
       });
 
       testGoldens('renders correctly (light theme)', (tester) async {