1

我试图弄清楚如何正确模拟这段代码。我已经想出了如何模拟成功，但我不知道如何模拟 catch/reject 块。

应用代码：

function getData(url = '') {
  return new Promise((resolve, reject) => {
    axios
      .get(`${baseURL}${url}`)
      .then((res) => {
        resolve(res.data);
      })
      .catch((err) => {
        reject(err);
      });
  });
}

在测试中我有：

import axios from 'axios';
const MockAdapter = require('axios-moc-adapter');

describe('getData', () => {
  it('test success', async () => {
    const mock = new MockAdapter(axios);

    mock.onGet(`${service.baseURL}/sites`).reply(200, 'success');
    const axiosSpy = jest.spyOn(axios, 'get');

    const rtn = await service.getData('/sites');

    expect(axiosSpy).toHaveBeenCalled();
    expect(rtn).toBe('success');
  });
  it('test failure', async () => {
    const mock = new MockAdapter(axios);

    mock.onGet(`${service.baseURL}/sites`).networkError();
    const rtn = await service.getData('/sites').catch((err) => {
      expect(err.message).toBe('message');
    });
    expect(rtn).toBe(undefined);
  });
});

测试成功测试有效，但是当我测试失败时，我得到：

    Expected: "message"
    Received: "Cannot read properties of undefined (reading 'then')"

      29 |     mock.onGet(`${service.baseURL}/sites`).networkError();
      30 |     const rtn = await service.getData('/sites').catch((err) => {
    > 31 |       expect(err.message).toBe('message');
         |                           ^
      32 |     });
      33 |     expect(rtn).toBe(undefined);
      34 |   });

如何编写成功通过失败案例的测试？具体来说，我可以通过不检查 catch 块内部来使这个测试通过，但是当我运行覆盖时，它不会覆盖 App 代码中的 catch 块。我怎样才能正确覆盖这条线？

4

1 回答 1

0

无法重现您的问题，但会使用message 而不是.networkError()引发错误，请参阅源代码index.js#L141'Network Error''message'

service.ts：

import axios from 'axios';

export const baseURL = 'http://localhost:3000/api';
export function getData(url = '') {
  return new Promise((resolve, reject) => {
    axios
      .get(`${baseURL}${url}`)
      .then((res) => {
        resolve(res.data);
      })
      .catch((err) => {
        reject(err);
      });
  });
}

service.test.ts：

import * as service from './service';
import axios from 'axios';
import MockAdapter from 'axios-mock-adapter';

describe('getData', () => {
  it('test success', async () => {
    const mock = new MockAdapter(axios);

    mock.onGet(`${service.baseURL}/sites`).reply(200, 'success');
    const axiosSpy = jest.spyOn(axios, 'get');

    const rtn = await service.getData('/sites');

    expect(axiosSpy).toHaveBeenCalled();
    expect(rtn).toBe('success');
  });
  it('test failure', async () => {
    const mock = new MockAdapter(axios);
    mock.onGet(`${service.baseURL}/sites`).networkError();
    const rtn = await service.getData('/sites').catch((err) => {
      expect(err.message).toBe('Network Error');
    });
    expect(rtn).toBe(undefined);
  });
  it('test failure 2', async () => {
    const mock = new MockAdapter(axios);

    mock.onGet(`${service.baseURL}/sites`).networkError();
    await expect(service.getData('/sites')).rejects.toThrowError('Network Error');
  });
});

测试结果：

 PASS  examples/69947398/service.test.ts (8.89 s)
  getData
    ✓ test success (5 ms)
    ✓ test failure (1 ms)
    ✓ test failure 2 (2 ms)

------------|---------|----------|---------|---------|-------------------
File        | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s 
------------|---------|----------|---------|---------|-------------------
All files   |     100 |        0 |     100 |     100 |                   
 service.ts |     100 |        0 |     100 |     100 | 4                 
------------|---------|----------|---------|---------|-------------------
Test Suites: 1 passed, 1 total
Tests:       3 passed, 3 total
Snapshots:   0 total
Time:        9.52 s
于 2021-11-15T08:17:31.040 回答