Exploring the capabilities of Firebase functions within a Vue.js environment

Question

Exploring the capabilities of Firebase functions within a Vue.js environment

I've been working on unit testing my Vue components, but it's posing challenges due to the integration with Firebase. To address this issue, I decided to set up a dedicated folder named __mocks__ for storing all my mocked functions. Within this folder, I created a file called firebase.js:

The content within the firebase.js file contains mock implementations for various Firebase functions such as createUserWithEmailAndPassword, signInWithEmailAndPassword, sendEmailVerification, and more. These mocks are necessary for accurately testing components that rely on Firebase interactions.

This firebase.js file was adapted from a repository found at: https://github.com/mrbenhowl/mocking-firebase-initializeApp-and-firebase-auth-using-jest

The specific component that requires testing is named EmailSignupLogin. In this case, the focus is on testing the registerViaEmail method:

Within the registerViaEmail method, there is logic to create a new user account via email authentication. Upon successful registration, the setUser method is invoked to update the user state and redirect them to a designated page.

To facilitate the testing process, a test file named email-signup-login.spec.js has been created:

The test file imports EmailSignupLogin component and utilizes mock data along with Jest functions to simulate user actions and verify expected outcomes during testing.

An anomaly has been detected while running tests - the mocked functions defined in the __mocks__/firebase.js file do not seem to be properly accessed. Any insights on what may be causing this discrepancy would be greatly appreciated!

javascript firebase unit-testing vue.js jestjs

Answer 1

Answer №1

A few issues have surfaced in your code:

registerViaEmail() is not async, therefore the await call exits prematurely, causing the test to assert something before it happens. To fix this, wrap the function body with a Promise:

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()
    }
  })
},

The referenced script is not meant for Jest __mocks__. It directly modifies the firebase object by replacing its mocks. To use it, import the script before importing the test module:

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

createUserWithEmailAndPassword currently does not return anything due to a missing continuation of returning the Promise. Ensure to return the Promise as intended:

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

createUserWithEmailAndPassword needs to be mocked in your auth object in EmailSignupLogin. Update your mock object accordingly:

jest.spyOn(firebase, 'auth').mockImplementation(() => ({
  onAuthStateChanged,
  currentUser: {
    displayName: 'testDisplayName',
    email: '<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="087c6d7b7c487c6d7b7c266b6765">[email protected]</a>',
    emailVerified: true,
  },
  getRedirectResult,
  sendPasswordResetEmail,
  createUserWithEmailAndPassword, //👈
}));

Your test setup mistakenly used a plain object instead of an instance of Vuex.Store for the store mocking:

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

Github demo

Answer 2

A few issues have surfaced in your code:

registerViaEmail() is not async, therefore the await call exits prematurely, causing the test to assert something before it happens. To fix this, wrap the function body with a Promise:

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()
    }
  })
},

The referenced script is not meant for Jest __mocks__. It directly modifies the firebase object by replacing its mocks. To use it, import the script before importing the test module:

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

createUserWithEmailAndPassword currently does not return anything due to a missing continuation of returning the Promise. Ensure to return the Promise as intended:

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

createUserWithEmailAndPassword needs to be mocked in your auth object in EmailSignupLogin. Update your mock object accordingly:

jest.spyOn(firebase, 'auth').mockImplementation(() => ({
  onAuthStateChanged,
  currentUser: {
    displayName: 'testDisplayName',
    email: '<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="087c6d7b7c487c6d7b7c266b6765">[email protected]</a>',
    emailVerified: true,
  },
  getRedirectResult,
  sendPasswordResetEmail,
  createUserWithEmailAndPassword, //👈
}));

Your test setup mistakenly used a plain object instead of an instance of Vuex.Store for the store mocking:

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

Github demo

Exploring the capabilities of Firebase functions within a Vue.js environment

Answer №1

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