错误迁移到更新的Flutter_Bloc＆amp;使用Mockito进行测试

Question

我试图在一个过时的flutter通讯应用程序的教程之后与Mockito一起进行测试。我正在尝试使用所有内容的最新版本。该教程刚刚实现了Flutter Bloc，现在我遇到了一个我不知道如何修复的错误。

这是测试：

import 'package:chat/chat.dart';
import 'package:flutter_test/flutter_test.dart';
import 'package:mockito/annotations.dart';
import 'package:mockito/mockito.dart';
import 'package:rethink_chat/states_management/message/message_bloc.dart';

import 'message_bloc_test.mocks.dart';

@GenerateMocks([IMessageService])
void main() {
  late MessageBloc sut;
  late MockIMessageService messageService; //changed to Mock
  late User user;

  setUp(() {
    messageService = MockIMessageService(); // FakeMessageService();
    user = User(
      username: 'test',
      photoUrl: '',
      active: true,
      lastseen: DateTime.now(),
    );
    sut = MessageBloc(messageService);
  });

  tearDown(() => sut.close());

  test('should emit message sent state when message is sent', () {
    final message = Message(
      from: '123',
      to: '456',
      contents: 'test message',
      timestamp: DateTime.now(),
    );

    when(messageService.send(message)).thenAnswer((_) async => true);
    when(messageService.dispose()).thenAnswer((_) async => <Object?>[]);
    sut.add(MessageEvent.onMessageSent(message));
    expectLater(sut.stream, emits(MessageState.sent(message)));
  });
}

这是错误：

Bad state: add(MessageSent) was called without a registered event handler.
Make sure to register a handler via on<MessageSent>((event, emit) {...})

这是message_event.dart：

part of 'message_bloc.dart';

abstract class MessageEvent extends Equatable {
  const MessageEvent();
  factory MessageEvent.onSubscribed(User user) => Subscribed(user);
  factory MessageEvent.onMessageSent(Message message) => MessageSent(message);

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

class Subscribed extends MessageEvent {
  final User user;
  const Subscribed(this.user);

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

class MessageSent extends MessageEvent {
  final Message message;
  const MessageSent(this.message);

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

class _MessageReceived extends MessageEvent {
  const _MessageReceived(this.message);

  final Message message;

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

and Message_bloc.dart：

import 'dart:async';

import 'package:bloc/bloc.dart';
import 'package:chat/chat.dart';
import 'package:equatable/equatable.dart';
//import 'package:rethink_chat/states_management/message/message_event.dart';
// import 'package:rethink_chat/states_management/message/message_state.dart';
//import 'package:chat/chat.dart';

part 'message_event.dart';
part 'message_state.dart';

class MessageBloc extends Bloc<MessageEvent, MessageState> {
  final IMessageService _messageService;
  StreamSubscription?
      _subscription; // added a ? but not sure if it's neutral, helpful or harmful

  MessageBloc(this._messageService) : super(MessageState.initial());

  @override
  Stream<MessageState> mapEventToState(MessageEvent event) async* {
    if (event is Subscribed) {
      await _subscription?.cancel();
      _subscription = _messageService
          .messages(activeUser: event.user)
          .listen((message) => add(_MessageReceived(message)));
    }

    if (event is _MessageReceived) {
      yield MessageState.received(event.message);
    }
    if (event is MessageSent) {
      await _messageService.send(event.message);
      yield MessageState.sent(event.message);
    }
  }

  @override
  Future<void> close() {
    _subscription?.cancel();
    _messageService.dispose();
    return super.close();
  }
}

我在另一个帖子中看到了在某个时刻删除mapeventTostate的一篇文章中，但我不知道如何如何解决这个问题？我对此非常陌生，以至于根据查看其他代码的示例，知道该特定代码要解决的问题很难。

请让我知道是否有其他信息会有所帮助，我将更新此帖子以包含它。我是一个总体初学者，因此希望这是我忽略的非常简单的修复程序。我非常感谢任何帮助。

编辑：对于类似的测试，我也会遇到类似的错误：

  test('should emit messages received from service', () {
    final message = Message(
      from: '123',
      to: '456',
      contents: 'test message',
      timestamp: DateTime.now(),
    );

    when(messageService.messages(activeUser: anyNamed('activeUser')))
        .thenAnswer((_) => Stream.fromIterable([message]));
    when(messageService.dispose()).thenAnswer((_) async => <Object?>[]);

    sut.add(MessageEvent.onSubscribed(user));
    expectLater(sut.stream, emitsInOrder([MessageReceivedSuccess(message)]));
  });

错误是

Bad state: add(Subscribed) was called without a registered event handler.
Make sure to register a handler via on<Subscribed>((event, emit) {...})

我认为这两个修复程序都应该相同，对吗？

EDIT2：因此，我认为我需要将放在＆lt; messagesent＆gt;（（（event，emit）{...}）{...}） and on＆lt; lt; code> on＆lt;（（event，emit）{。 ..}）代码中的某个地方，但是在哪里？

Answer 1

查看迁移指南 https://bloclibrary.dev/#/migration

仍然版本7.1或更低。您首先需要跟随7.1到7.2的迁移。这将向您展示如何将mapeventTostate迁移到新的on Event＆gt;格式。