面试题：Flutter中如何使用Mockito进行网络请求的Mock测试

添加依赖：在pubspec.yaml文件中添加mockito和test依赖：
```
dev_dependencies:
  mockito: ^5.4.2
  test: ^1.22.0
```
然后运行flutter pub get下载依赖。

生成Mock代码：假设网络请求使用的Dio实例如下定义：

import 'package:dio/dio.dart';

class UserApi {
  final Dio dio;
  UserApi(this.dio);

  Future<Response> getUserInfo() async {
    return await dio.get('/user/info');
  }
}

使用build_runner生成Dio的Mock代码。首先确保build_runner在dev_dependencies中：

dev_dependencies:
  build_runner: ^2.3.1

运行flutter pub run build_runner build，会在项目根目录下的test/mocks目录（需自行创建）生成MockDio.dart文件：

// Mocks generated by Mockito 5.4.2 from annotations
// in my_project/test/user_api_test.dart.
// Do not manually edit this file.

import 'package:dio/dio.dart' as _i2;
import 'package:mockito/mockito.dart' as _i1;

// ignore: comment_references
/// A class which mocks [Dio].
// ignore: must_be_immutable
class MockDio extends _i1.Mock implements _i2.Dio {
}

定义Mock对象、设置返回值以及进行断言验证：

import 'package:flutter_test/flutter_test.dart';
import 'package:mockito/mockito.dart';
import 'package:dio/dio.dart';
import '../lib/user_api.dart';

// 引入生成的MockDio
import 'mocks/MockDio.dart';

void main() {
  group('UserApi', () {
    late MockDio mockDio;
    late UserApi userApi;

    setUp(() {
      mockDio = MockDio();
      userApi = UserApi(mockDio);
    });

    test('getUserInfo should return a successful response', () async {
      // 设置MockDio的get方法返回值
      when(mockDio.get('/user/info')).thenAnswer((_) async => Response(
            requestOptions: RequestOptions(path: '/user/info'),
            statusCode: 200,
            data: {'name': 'John Doe'},
          ));

      // 调用被测试方法
      final response = await userApi.getUserInfo();

      // 断言验证
      expect(response.statusCode, 200);
      expect(response.data, {'name': 'John Doe'});
      verify(mockDio.get('/user/info')).called(1);
    });
  });
}

上述代码中：

添加依赖：确保mockito、test以及build_runner依赖被正确添加并下载。
生成Mock代码：利用build_runner根据Dio生成Mock类MockDio。
测试代码：在测试用例中，定义MockDio对象，通过when方法设置MockDio的get方法返回模拟的Response，调用userApi.getUserInfo()进行网络请求模拟，最后使用expect进行返回值断言，使用verify验证get方法是否被调用。

面试题：Flutter中如何使用Mockito进行网络请求的Mock测试

知识考点

面试题答案