问PlatformException (PlatformException(通道错误，无法在通道上建立连接，null，null))，同时模拟使用防火墙的方法

EN

Future<MediasState> loadMedias(AbstractEvent event) async {
    late AbstractBlocState streamState;
    try {
      DataHelper _dataHelperMediasEvent = DataHelperFactory.instance
          .createInstanceFromAnotherDataHelperAndEntityInstance(
              _dataHelperEvents, event, 'medias');
      List<AbstractMedia> medias =
          (await _dataHelperMediasEvent.getAll()).cast<AbstractMedia>();
      for (AbstractMedia media in medias) {
        media.user = await (_dataHelperUsers.getEntity(media.user.get()));
      }
      medias = sortEntitiesByCreatedDateDesc(medias) as List<AbstractMedia>;
      streamState = MediasShowed(medias);
    } catch (error) {
      streamState = MediasShowedError();
    } finally {
      return streamState as MediasState;
    }
  }

 test('Test load medias', () async {
  WidgetsFlutterBinding.ensureInitialized();
  await Firebase.initializeApp();
    AbstractEvent event =
        EntityFactory.createInstance('Event') as AbstractEvent;

    AbstractMedia media1 =
        EntityFactory.createInstance('Media') as AbstractMedia;

    AbstractMedia media2 =
        EntityFactory.createInstance('Media') as AbstractMedia;

    AbstractMedia media3 =
        EntityFactory.createInstance('Media') as AbstractMedia;

    List<AbstractMedia> listOfMedias = <AbstractMedia>[];

    listOfMedias.add(media1);
    listOfMedias.add(media2);
    listOfMedias.add(media3);

    when(mockMediasEvent.loadMedias(event))
        .thenAnswer((_) async => MediasShowed(listOfMedias));

    blocMedias.add(LoadMediaOfOneEvent(event));

    await expectLater(blocMedias.state, isA<MediasShowedError>());
  });

class DataHelper {
  DataHelper.initialize(String collectionPath) {
    this.setCollection(collectionPath);
  }

  late String collectionPath;
  late String className;
  late CollectionReference<Map<String, dynamic>> collection;

  final FirebaseFirestore firebaseFirestore = FirebaseFirestore.instance;