如何在 bloc 单元测试中模拟连接性？

Question

I'm using this package and I have a following connectivity in a bloc

Connectivity _connectivity = Connectivity();
StreamSubscription _connectivityStreamSubscription;

ConnectivityBloc() {
    _connectivityStreamSubscription = _connectivity.onConnectivityChanged.listen((connectivityResult) {
      if (connectivityResult == ConnectivityResult.wifi) {
        add(ConnectivityEventConnectEvent());
      } else {
        add(ConnectivityEventDisconnectEvent());
      }
    });
  }

I'm trying to test the bloc, however I'm struggling to mock the StreamSubscription in unit tests. So how can we mock StreamSubscription in bloc_test?

Answer 1

I've figured it out I didn't pass the instance of Connectivity to bloc.

ConnectivityBloc(this._connectivity) {

I have mocked the Connectivity with Mockito.

class MockConnectivity extends Mock implements Connectivity {}

and then I could just pass the Stream with ConnectivityResult I wanted

when(mockConnectivity.onConnectivityChanged).thenAnswer(
      (_) => Stream<ConnectivityResult>.fromIterable([ConnectivityResult.mobile, ConnectivityResult.wifi]));