开玩笑的模拟无法解决每个注入的值

问题描述

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

// 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 = '[e-mail]';
    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]);
  });
});

测试在第一个断言上通过，但在第二个断言上失败。测试两次都返回相同的{ uid: 'foo-bar' }对象，但我希望第二次返回测试响应值null。我想念什么？

解决方法

每次getUserByEmail调用都会创建一个新的auth间谍，但不会被多次调用。

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));
...

,

对于每个测试用例，您都可以使用getUserByEmail方法来模拟一次解析的值。

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/stackoverflow/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