Flutter test , stubbing a method that uses dartz fails

0
votes

Here's the implicated methods of the cubit I'm testing:

  void authCheck() {
    if (_authUser != null) {
      emit(AuthState.authenticated(_authUser!));
      if (kDebugMode) {
        // ignore: avoid_print
        print(_authUser!);
      }
    } else {
      emit(const AuthState.unauthenticated());
      signInAnonymously();
    }
  }

  Future<void> signInAnonymously() async {
    final either = await _authRepository.signInAnonymously();
    either.fold(
      (failure) => _showFailureToast(failure),
      (auth) => emit(AuthState.authenticated(_authUser!)),
    );
  }

I'm testing the unauthenticated part of authCheck, here's the test:

 blocTest('should emit [Unauthenticated] when user is not authenticated',
    build: () {
      when(authCubit.signInAnonymously())
          .thenAnswer((_) => Future.value(null));
      when(mockIAuthRepository.getSignedInUser()).thenReturn(null);
      return authCubit;
    },
    act: (AuthCubit authcubit) {
      authcubit.authCheck();
    },
    expect: () => [const AuthState.unauthenticated()]);

But when stubbing authCubit.signInAnonymously to return a Future<void> I get this error:

UnimplementedError: fold
package:test_api                                          Fake.noSuchMethod
package:dartz/src/either.dart 8:5                         _FakeEither_0.fold
package:mage_duel/application/auth/auth_cubit.dart 38:12  AuthCubit.signInAnonymously
===== asynchronous gap ===========================
dart:async                                                _asyncThenWrapperHelper
test/application/auth/auth_cubit_test.dart 51:26          main.<fn>.<fn>
package:bloc_test/src/bloc_test.dart 196:29               testBloc.<fn>.<fn>
===== asynchronous gap ===========================
dart:async                                                _asyncThenWrapperHelper
package:bloc_test/src/bloc_test.dart                      testBloc.<fn>.<fn>
dart:async                                                runZonedGuarded
package:bloc_test/src/bloc_test.dart 192:13               testBloc.<fn>
package:bloc_test/src/bloc_test.dart 191:5                testBloc.<fn>
dart:async                                                runZoned
package:bloc/src/bloc_overrides.dart 46:26                BlocOverrides.runZoned
package:bloc_test/src/bloc_test.dart 190:23               testBloc
package:bloc_test/src/bloc_test.dart 156:13               blocTest.<fn>
package:bloc_test/src/bloc_test.dart 155:5                blocTest.<fn>
type 'Future<void>' is not a subtype of type 'Future<Either<AuthFailure, Unit>>' in type cast
test/application/auth/auth_cubit_test.mocks.dart 50:11    MockIAuthRepository.signInAnonymously
package:mage_duel/application/auth/auth_cubit.dart 37:42  AuthCubit.signInAnonymously
package:mage_duel/application/auth/auth_cubit.dart 32:7   AuthCubit.authCheck
test/application/auth/auth_cubit_test.dart 57:21          main.<fn>.<fn>
package:bloc_test/src/bloc_test.dart 201:24               testBloc.<fn>.<fn>
===== asynchronous gap ===========================
dart:async                                                _completeOnAsyncError
package:mage_duel/application/auth/auth_cubit.dart        AuthCubit.signInAnonymously
package:mage_duel/application/auth/auth_cubit.dart 32:7   AuthCubit.authCheck
test/application/auth/auth_cubit_test.dart 57:21          main.<fn>.<fn>
package:bloc_test/src/bloc_test.dart 201:24               testBloc.<fn>.<fn>
===== asynchronous gap ===========================
dart:async                                                _asyncThenWrapperHelper
package:bloc_test/src/bloc_test.dart                      testBloc.<fn>.<fn>
dart:async                                                runZonedGuarded
package:bloc_test/src/bloc_test.dart 192:13               testBloc.<fn>
package:bloc_test/src/bloc_test.dart 191:5                testBloc.<fn>
dart:async                                                runZoned
package:bloc/src/bloc_overrides.dart 46:26                BlocOverrides.runZoned
package:bloc_test/src/bloc_test.dart 190:23               testBloc
package:bloc_test/src/bloc_test.dart 156:13               blocTest.<fn>
package:bloc_test/src/bloc_test.dart 155:5                blocTest.<fn>
fluttermockitoflutter-testblocdartz