javascript - 在 vuejs 中测试 firebase 函数

Question

我想对我的 vue 组件进行单元测试。由于我正在使用 firebase，所以这有点困难。

首先，我创建了一个 __mocks__ 文件夹来包含我所有的模拟函数。在该文件夹中，我创建了 firebase.js:

import * as firebase from 'firebase';

const onAuthStateChanged = jest.fn();

const getRedirectResult = jest.fn(() => Promise.resolve({
  user: {
    displayName: 'redirectResultTestDisplayName',
    email: 'redirectTest@test.com',
    emailVerified: true,
  },
}));

const sendEmailVerification = jest.fn(() => Promise.resolve('result of sendEmailVerification'));

const sendPasswordResetEmail = jest.fn(() => Promise.resolve());

const createUserWithEmailAndPassword = jest.fn(() => {
  console.log('heeeeelllo');
  Promise.resolve({
    user: {
      displayName: 'redirectResultTestDisplayName',
      email: 'redirectTest@test.com',
      emailVerified: true,
    },
  });
});

const signInWithEmailAndPassword = jest.fn(() => Promise.resolve('result of signInWithEmailAndPassword'));

const signInWithRedirect = jest.fn(() => Promise.resolve('result of signInWithRedirect'));

const initializeApp = jest // eslint-disable-line no-unused-vars
  .spyOn(firebase, 'initializeApp')
  .mockImplementation(() => ({
    auth: () => ({
      createUserWithEmailAndPassword,
      signInWithEmailAndPassword,
      currentUser: {
        sendEmailVerification,
      },
      signInWithRedirect,
    }),
  }));

jest.spyOn(firebase, 'auth').mockImplementation(() => ({
  onAuthStateChanged,
  currentUser: {
    displayName: 'testDisplayName',
    email: 'test@test.com',
    emailVerified: true,
  },
  getRedirectResult,
  sendPasswordResetEmail,
}));

firebase.auth.FacebookAuthProvider = jest.fn(() => {});
firebase.auth.GoogleAuthProvider = jest.fn(() => {});

这个文件，我取自:https://github.com/mrbenhowl/mocking-firebase-initializeApp-and-firebase-auth-using-jest

我要测试的组件称为 EmailSignupLogin。在这种特殊情况下，我想测试 registerViaEmail 方法:

methods: {
    registerViaEmail() {
      if (this.password.length > 0 && this.password === this.passwordReenter) {
        firebase.auth().createUserWithEmailAndPassword(this.emailAdress, this.password).then((result) => {
          const { user } = result;
          console.log(result);
          this.setUser(user);
          this.$router.push('/stocks');
        }).catch((error) => {
          const errorCode = error.code;
          const errorMessage = error.message;
          this.error = errorMessage;
          console.error(errorCode, errorMessage);
        });
      } else {
        this.error = 'passwords not matching';
      }
    },
  },

现在我的测试文件(email-signup-login.spec.js):

import { mount } from '@vue/test-utils';
import Vue from 'vue';
import EmailSignupLogin from '@/components/email-signup-login';

jest.mock('../../__mocks__/firebase');

describe('EmailSignupLogin', () => {
  let wrapper;
  const mockFunction = jest.fn();

  beforeEach(() => {
    wrapper = mount(EmailSignupLogin, {
      data() {
        return {
          password: '123456',
          passwordReenter: '123456',
          emailAdress: 'test@test.com',
        };
      },
      store: {
        actions: {
          setUser: mockFunction,
        },
      },
    });
  });

  describe('methods', () => {
    describe('#registerViaEmail', () => {
      it('calls mockFunction', async () => {
        await wrapper.vm.registerViaEmail();

        expect(mockFunction).toHaveBeenCalled();
      });
    });
  });
});

在 registerViaEmail 方法中，我调用了 setUser 操作，这是一个 vuex 操作。

问题是它似乎没有从 __mocks__/firebase.js 调用我模拟的函数。谁能告诉我为什么？

Answer 1

您的代码中出现了几个问题:

1. registerViaEmail() 不是 async(不返回 Promise)，因此 await 调用过早返回，此时您的测试会尝试断言尚未发生的事情。要解决这个问题，只需用 Promise 包裹函数体:

registerViaEmail() {
  return new Promise((resolve, reject) => {
    if (this.password.length > 0 && this.password === this.passwordReenter) {
      firebase.auth().createUserWithEmailAndPassword(this.emailAdress, this.password).then((result) => {
        //...
        resolve()
      }).catch((error) => {
        //...
        reject()
      });
    } else {
      //...
      reject()
    }
  })
},

1. script你提到的不打算与 Jest __mocks__ 一起使用。脚本本身直接修改 firebase 对象，用模拟替换它的方法/属性。要使用该脚本，您只需要在导入使用firebase的测试模块之前导入它:

import './firebase-mock' // <-- order important
import EmailSignupLogin from '@/components/EmailSignupLogin'

1. createUserWithEmailAndPassword 不返回任何内容。好像是originally returned the Promise ，但是你用console.log修改了它，忘记继续返回Promise，这阻止了这个方法被awaited(相同作为 #1 发行)。解决方案是返回 Promise:

const createUserWithEmailAndPassword = jest.fn(() => {
  console.log('heeeeelllo')
  return /*👈*/ Promise.resolve(/*...*/)
})

1. createUserWithEmailAndPassword 是要在 EmailSignupLogin 中测试的方法，但它目前未在您的 auth 模拟对象中模拟。它仅在 initializeApp.auth 的返回中被模拟，但这不是它在 EmailSignupLogin 中使用的内容。要解决此问题，请将 createUserWithEmailAndPassword 复制到您的 auth 模拟对象:

jest.spyOn(firebase, 'auth').mockImplementation(() => ({
  onAuthStateChanged,
  currentUser: {
    displayName: 'testDisplayName',
    email: 'test@test.com',
    emailVerified: true,
  },
  getRedirectResult,
  sendPasswordResetEmail,
  createUserWithEmailAndPassword, //👈
}));

1. 在你的测试设置中，你用一个普通对象模拟了商店，但它实际上需要是 Vuex.Store 的一个实例:

mount({
  //store: { /*...*/ },              //❌DON'T DO THIS
  store: new Vuex.Store({ /*...*/ }) //✅
})

Github demo