Question

为此我进行了很多搜索，我认为解决方案似乎有些拙劣，对于我认为应该是一件相当简单的任务并不简单。

我有以下课程

// client.ts
export interface myClient {
  getClient: (customerId: string) => Promise<string>;
}

const impClient = (): myClient => {   

  return {
    getClient: async (customerId: string) => {
     // Implementation
    }
  };
};

export default impClient;

我正在尝试使用默认实现来对此进行嘲笑。我尝试了很多方法，包括

 jest.mock('./client', () =>
    jest.fn().mockImplementation(() => {
      return () => {
        return {
          getClient: () => {
            return Promise.resolve('abcde');
          }
        };
      };
    })
  );

但是它们似乎都不起作用。有人可以帮忙澄清一下吗？

Answer 1

这是解决方案：

client.ts：

export interface myClient {
  getClient: (customerId: string) => Promise<string>;
}

const impClient = (): myClient => {
  return {
    getClient: async (customerId: string) => {
      return customerId;
    }
  };
};

export default impClient;

main.ts，main函数使用impClient

import impClient from './client';

export function main(customerId) {
  return impClient().getClient(customerId);
}

main.spec.ts：

import { main } from './main';
import impClient from './client';

jest.mock('./client.ts', () => {
  const mockedClient = {
    getClient: jest.fn()
  };
  return jest.fn(() => mockedClient);
});

const client = impClient();

describe('main', () => {
  afterEach(() => {
    jest.resetAllMocks();
  });
  it('should return client correctly', async () => {
    (client.getClient as jest.MockedFunction<typeof client.getClient>).mockResolvedValueOnce('abcde');
    const customerId = '1';
    const actualValue = await main(customerId);
    expect(actualValue).toBe('abcde');
  });
});

覆盖率100％的单元测试结果：

 PASS  src/stackoverflow/58107885/main.spec.ts (9.342s)
  main
    ✓ should return client correctly (4ms)

----------|----------|----------|----------|----------|-------------------|
File      |  % Stmts | % Branch |  % Funcs |  % Lines | Uncovered Line #s |
----------|----------|----------|----------|----------|-------------------|
All files |      100 |      100 |      100 |      100 |                   |
 main.ts  |      100 |      100 |      100 |      100 |                   |
----------|----------|----------|----------|----------|-------------------|
Test Suites: 1 passed, 1 total
Tests:       1 passed, 1 total
Snapshots:   0 total
Time:        12.052s

以下是完整的演示：https://github.com/mrdulin/jest-codelab/tree/master/src/stackoverflow/58107885

开玩笑嘲笑打字稿导入作为依赖项

1 个答案: