Jest mock 没有解决每个注入的值

Question

我正在尝试在我的 functions/send.js 模块中测试名为 myCloudFn 的 Firebase 云函数。我的测试在 functions/test/send.spec.js:

// send.js
const admin = require('firebase-admin');

async function myCloudFn (email) {
  const authUser = await admin.auth().getUserByEmail(email);
  return authUser;
}

module.exports = { myCloudFn };

// send.spec.js
const send = require('../send.js');

jest.mock('firebase-admin', () => ({
  auth: () => ({
    getUserByEmail: jest.fn()
      .mockResolvedValueOnce({ uid: 'foo-bar' })
      .mockResolvedValueOnce(null),
  }),
}));

describe('send.js', () => {
  it('returns authUser from myCloudFn()', async () => {
    const email = 'foo@bar.com';
    const responseOptions = [{ uid: 'foo-bar' }, null];
    const responsePromises = responseOptions.map(() => send.myCloudFn(email));
    const responses = await Promise.all(responsePromises);
    expect(responses[0]).toStrictEqual(responseOptions[0]);
    expect(responses[1]).toStrictEqual(responseOptions[1]);
  });
});

测试通过第一个断言，但在第二个断言上失败。两次测试 returns 相同的 { uid: 'foo-bar' } 对象，但我希望第二次的测试响应值为 null。我错过了什么？

Answer 1

每次 auth 调用都会创建一个新的 getUserByEmail 间谍程序，它不会被调用超过一次。

相反，它应该是：

const mockGetUserByEmail = jest.fn();
jest.mock('firebase-admin', () => ({
  auth: () => ({
    getUserByEmail: mockGetUserByEmail
  })
}));

...
mockGetUserByEmail
  .mockResolvedValueOnce({ uid: 'foo-bar' })
  .mockResolvedValueOnce(null);
const responsePromises = responseOptions.map(() => send.myCloudFn(email));
...

Answer 2

您可以为每个测试用例模拟一次 getUserByEmail 方法的解析值。

例如

send.js:

const admin = require('firebase-admin');

async function myCloudFn(email) {
  const authUser = await admin.auth().getUserByEmail(email);
  return authUser;
}

module.exports = { myCloudFn };

send.test.js:

const { myCloudFn } = require('./send');
const admin = require('firebase-admin');

jest.mock(
  'firebase-admin',
  () => {
    const mAdmin = {
      auth: jest.fn().mockReturnThis(),
      getUserByEmail: jest.fn(),
    };
    return mAdmin;
  },
  { virtual: true },
);

describe('send.js', () => {
  afterAll(() => {
    jest.resetAllMocks();
  });
  it('should returns authUser from myCloudFn()', async () => {
    admin.auth().getUserByEmail.mockResolvedValueOnce({ uid: 'foo-bar' });
    const actual = await myCloudFn();
    expect(actual).toEqual({ uid: 'foo-bar' });
  });
  it('should return null', async () => {
    admin.auth().getUserByEmail.mockResolvedValueOnce(null);
    const actual = await myCloudFn();
    expect(actual).toBeNull();
  });
});

单元测试结果：

 PASS  src/Whosebug/64575307/send.test.js (14.349s)
  send.js
    ✓ should returns authUser from myCloudFn() (11ms)
    ✓ should return null (3ms)

----------|----------|----------|----------|----------|-------------------|
File      |  % Stmts | % Branch |  % Funcs |  % Lines | Uncovered Line #s |
----------|----------|----------|----------|----------|-------------------|
All files |      100 |      100 |      100 |      100 |                   |
 send.js  |      100 |      100 |      100 |      100 |                   |
----------|----------|----------|----------|----------|-------------------|
Test Suites: 1 passed, 1 total
Tests:       2 passed, 2 total
Snapshots:   0 total
Time:        17.321s

Jest mock 没有解决每个注入的值

Jest mock not resolving to each injected value

javascript

unit-testing

jestjs

google-cloud-functions

firebase-admin