Mockito BlocTest“‘Null’类型不是‘Future<UserModel>’类型的子类型”

Question

我正在嘲笑我使用 firebase 的注册功能。我的问题是，当我在 BlocTest 中调用构建器时，不知何故它的值变为 null。我不明白，因为 kMockTeacher 在我的 user_model.dart 中被定义为 UserModel：

final kMockTeacher = UserModel(
    firstName: 'Logan',
    lastName: 'V',
    email: '[email protected]',
    role: UserRole.teacher,
    token: '',
    id: '1');

构建：auth_test.dart中的()

 when(
          authService.signUpWithEmailAndPassword(registrationModel),
        ).thenReturn(
          Future<UserModel>.value(kMockTeacher),
        );

services.dart

Future<UserModel> signUpWithEmailAndPassword(
    final UserRegistrationModel user,
  );

auth_test.dart：

import 'package:bloc_test/bloc_test.dart';
import 'package:edtech/backend/services/services.dart';
import 'package:edtech/blocs/auth_cubit/auth_bloc.dart';
import 'package:edtech/models/models.dart';
import 'package:flutter_test/flutter_test.dart';
import 'package:mockito/mockito.dart';

class MockedDatabaseService extends Mock implements DatabaseService {}

class MockedAuthService extends Mock implements AuthService {}

void main() {
  group("Test Sign Up functions", () {
    late AuthService authService;
    late DatabaseService databaseService;
    late AuthBloc bloc;
    late UserRegistrationModel registrationModel;

    setUpAll(() {
      authService = MockedAuthService();
      databaseService = MockedDatabaseService();
      registrationModel = UserRegistrationModel(
          password: 'password',
          firstName: kMockTeacher.firstName,
          lastName: kMockTeacher.lastName,
          email: kMockTeacher.email,
          role: kMockTeacher.role);
      bloc = AuthBloc(UnAuthenticatedState(), authService);
    });

    blocTest<AuthBloc, AuthState>(
      'emits AuthLoading followed by AuthenticatedState',

      build: () {
        when(
          authService.signUpWithEmailAndPassword(registrationModel),
        ).thenReturn(
          Future<UserModel>.value(kMockTeacher),
        );

        return bloc;
      },
      act: (bloc) => bloc.signUp(user: registrationModel),
      expect: () => [
        AuthLoadingState(),
        AuthenticatedState(user: kMockTeacher),
      ],
    );

    tearDown(() {
      bloc.close();
    });
  });
}

我在调试模式下运行了测试，试图获取

          Future<UserModel>.value(kMockTeacher),

的值，但在获取它之前编译失败了。

Answer 1

使用 thenReturn 返回 Future 或 Stream 将抛出

ArgumentError

。

由于您的

authService.signUpWithEmailAndPassword(registrationModel)

返回 Future，因此您必须使用 thenAnswer。

when(
  authService.signUpWithEmailAndPassword(registrationModel),
).thenAnswer((_) => Future<UserModel>.value(kMockTeacher));

请参阅有关异步存根的快速说明以获取更多信息。