Express+TypeScript项目Jest配置及测试代码报错求助

编译错误：watchTimeFactory.build() 提示类型不可调用 #

错误信息：

This expression is not callable.
Type 'WatchTime' has no call signatures.ts(2349)

相关代码 #

测试文件 /test/unit/services/episodeService.spec.ts 片段：

it('When has no watchTime then create it', async ()=> {
    const watchTime: WatchTime =  watchTimeFactory.build() 
    // ... 其他代码
})

工厂文件 /test/factories/watchTime.ts：

/*some imports*/
export const watchTimeFactory = Factory.makeFactory<WatchTime>(() => ({
    userId: Number(faker.random.numeric()),
    episodeId: Number(faker.random.numeric()),
    seconds: Number(faker.random.numeric()),
    createdAt: new Date(),
    updatedAt: new Date()
}))

运行时错误：Mock方法无mockReturnValue #

将工厂调用移到测试用例外部后，编译错误消失，但出现新错误：

TypeError: episodesQueryServiceMock.findByUserIdAndEpisodeId.mockReturnValue is not a function

相关测试代码片段 #

beforeEach(() =>{
    jest.mock('../../../src/services/queries/episodesQueryService')
    jest.mock('../../../src/models/')
    jest.mock('../../../src/models/WatchTime')
    episodesQueryServiceMock =  episodesQueryService as jest.Mocked<typeof episodesQueryService>
})

Jest配置文件 ./jest.config.ts #

import type {Config} from '@jest/types';
const config: Config.InitialOptions = {
    verbose: true,
    transform: {
        '^.+\\.tsx?$': 'ts-jest',
    },
    setupFiles: ['<rootDir>/test/setup.ts'],
    testEnvironment: 'node',
    maxWorkers: 1,
    preset: 'ts-jest'
};
export default config;

解决方案 #

1. 修复工厂函数编译错误 #

• 检查测试文件中WatchTime的导入：确保导入的是类型定义（接口/类型别名）而非类。如果WatchTime是ORM模型类，应使用InstanceType<typeof WatchTime>作为工厂的泛型参数，而非类本身。
• 调整工厂泛型类型：

  // 假设WatchTime是模型类
  import { WatchTime } from '../../src/models/WatchTime';
  export const watchTimeFactory = Factory.makeFactory<InstanceType<typeof WatchTime>>(() => ({
      // ... 字段定义
  }))
  

• 测试文件中对应调整类型注解：

  const watchTime: InstanceType<typeof WatchTime> = watchTimeFactory.build();
  

2. 修复Mock方法运行时错误 #

• 将jest.mock移到文件顶部：Jest会自动将jest.mock提升到模块作用域最顶部，放在beforeEach中不会正确生效，导致原模块未被Mock替换。
• 调整测试文件结构：

  /*some imports*/
  // 移到文件顶部
  jest.mock('../../../src/services/queries/episodesQueryService')
  jest.mock('../../../src/models/')
  jest.mock('../../../src/models/WatchTime')
  
  describe('Episodes Service', () => {
      let episodesQueryServiceMock: jest.Mocked<typeof episodesQueryService>
      let watchTimeInstance: jest.Mocked<WatchTimeInstance>
  
      beforeEach(() =>{
          // 重置Mock状态
          jest.clearAllMocks();
          episodesQueryServiceMock = episodesQueryService as jest.Mocked<typeof episodesQueryService>
      })
  
      // ... 测试用例
  })
  

• 确认导出方式：如果episodesQueryService是默认导出，需调整Mock获取方式：

  episodesQueryServiceMock = require('../../../src/services/queries/episodesQueryService').default as jest.Mocked<typeof episodesQueryService>
  

3. 额外检查点 #

• 确认ts-jest与TypeScript版本兼容，避免版本冲突导致类型解析异常。
• 检查WatchTimeInstance定义：确保它是模型实例的正确类型，而非类本身，避免watchTimeInstance未被正确Mock。

内容的提问来源于stack exchange，提问作者Jose Luiz Junior