Flutter - Mockito - 在测试中使用 async 会产生错误，但使用 async* 可以正常工作吗？

Question

简而言之，我正在学习 ResoCoder TDD 课程。该课程有点过时，但我很确定遵循并一路进行调整是可以的。本课程的课程和 GitHub 中的代码不是空安全的。

而且我没有完全按照课程进行。我在这里和那里做了一些改变。

我刚刚进入该课程的第 2 集或第 3 集以了解背景。

auth_usecases_test.dart

import 'package:dartz/dartz.dart';
import 'package:mockito/mockito.dart';
import 'package:storayge/core/auth/domain/entities/local_user.dart';
import 'package:storayge/core/auth/domain/repository/auth_repository.dart';
import 'package:flutter_test/flutter_test.dart';
import 'package:storayge/core/auth/domain/usecases/auth_usecases.dart';

class MockAuthRepository extends Mock implements AuthRepository {}

void main() {
  late GetLocalUserDataFromRemote usecase;
  late MockAuthRepository mockAuthRepository;

  late String tUid;
  late LocalUser tLocalUser;

  setUp(() {
    mockAuthRepository = MockAuthRepository();
    usecase = GetLocalUserDataFromRemote(repository: mockAuthRepository);
    tLocalUser = const LocalUser(
      username: 'testUsername',
      email: 'testEmail@Email',
      uid: 'testUid',
    );
    tUid = 'testUid';
  });

  test(
    'should get LocalUser data from the repository',
    () async* {
      // arrange
      when(mockAuthRepository.getLocalUserDataFromRemote(uid: tUid))
          .thenAnswer((_) async => Right(tLocalUser));
      // act
      final result = await usecase(Params(uid: tUid));
      // assert
      expect(result, equals(Right(tLocalUser)));
      verify(mockAuthRepository.getLocalUserDataFromRemote(uid: tUid));
      verifyNoMoreInteractions(mockAuthRepository);
    },
  );
}

这是“工作”代码。如果我将async*关键字更改为 justasync它会产生此错误：

type 'Null' is not a subtype of type 'Future<Either<Failure, LocalUser>>'

auth_usecases.dart

class GetLocalUserDataFromRemote implements Usecase<LocalUser, Params> {
  final AuthRepository repository;

  GetLocalUserDataFromRemote({required this.repository});

  @override
  Future<Either<Failure, LocalUser>> call(Params params) async {
    return repository.getLocalUserDataFromRemote(uid: params.uid);
  }
}

class Params extends Equatable {
  final String uid;

  Params({required this.uid});

  @override
  List<Object?> get props => [uid];
}

auth_repository.dart

import 'package:dartz/dartz.dart';

import '../../../errors/failures.dart';
import '../entities/local_user.dart';

abstract class AuthRepository {
  Future<Either<Failure, LocalUser>> getLocalUserDataFromRemote({
    required String uid,
  });

  Future<Either<Failure, LocalUser>> signInWithEmailAndPassword({
    required String email,
    required String password,
  });
}

本地用户.dart

class LocalUser extends Equatable {
  final String username;
  final String email;
  final String uid;

  const LocalUser({
    required this.username,
    required this.email,
    required this.uid,
  });

  @override
  List<Object?> get props => [username, email, uid];
}

失败.dart

abstract class Failure extends Equatable {
  final List<Object> properties;

  const Failure({required this.properties});

  @override
  List<Object> get props => properties;
}

为什么以及如何更改异步标签使其发挥作用？我很困惑。

编辑：我的软件包目前都是最新的，具有良好的空安全性。除了我使用 0.1.0-nullsafety.1 的 dartz

编辑2：一些更新。首先，似乎使用 async* 标签使测试通过，但它似乎实际上不起作用。我的意思是测试即使在不应该通过的情况下也通过了。我想我已经找到了解决方案。这当然是我的错。mockito 文档说，mockito 确实支持 null 安全，但支持一些代码生成。使用自定义模拟类等等。我什么也没做，这很愚蠢，我讨厌自己。所以我会做一些，稍后更新。

Answer 1

好的。我终于找到了答案。是的，这是我自己的愚蠢错误。基本上，mockito 5.0.0 现在确实支持空安全，但有一些注意事项。您将需要使用一些代码生成来生成模拟类。我没有。基本上我所做的是

class MockAuthRepository extends Mock implements AuthRepository {} // remove

@GenerateMocks([AuthRepository]) //new
void main() {
  late GetLocalUserDataFromRemote usecase;
  late MockAuthRepository mockAuthRepository;

  late String tUid;
  late LocalUser tLocalUser;

  setUp(() {
    mockAuthRepository = MockAuthRepository();
    usecase = GetLocalUserDataFromRemote(repository: mockAuthRepository);
    tLocalUser = const LocalUser(
      username: 'testUsername',
      email: 'testEmail@Email',
      uid: 'testUid',
    );
    tUid = 'testUid';
  });

  test(
    'should get LocalUser data from the repository',
    () async {
      // arrange
      when(mockAuthRepository.getLocalUserDataFromRemote(anyNamed('uid')))
          .thenAnswer((_) async => Right(tLocalUser));
      // act
      final result = await usecase(Params(uid: tUid));
      // assert
      expect(result, equals(Right(tLocalUser)));
      verify(mockAuthRepository.getLocalUserDataFromRemote(uid: tUid));
      verifyNoMoreInteractions(mockAuthRepository);
    },
  );
}

并使用构建运行器生成它。这很容易。我就是太笨了，没有仔细阅读文档。