CODEWITHSUNDEEP
reactjsfirebaseunit-testingreact-nativejestjs
mattmuirhead
mattmuirhead

Reputation: 73

Testing firebase.messaging().subscribeToTopic() in React-Native with Jest

I'm creating tests in Jest to ensure that a function is working correctly. In my test, I fire off my function and check that the function inside has been called. However, I get the error:

received value must be a mock or spy function.

As far as I'm aware I'm mocking firebase correctly and looking for the correct function. Any help would be hugely appreciated.

This is the function in question, in the notifications.js file:

export async function subscribeToTopic(topic) {
    await firebase.messaging().subscribeToTopic(topic)
}

I've mocked firebase in a setupTest.js file

import 'react-native-firebase'

jest.mock('react-native-firebase', () => ({
  messaging: jest.fn(() => ({
    hasPermission: jest.fn(() => Promise.resolve(true)),
    subscribeToTopic: jest.fn(),
    unsubscribeFromTopic: jest.fn(),
    requestPermission: jest.fn(() => Promise.resolve(true)),
    getToken: jest.fn(() => Promise.resolve('myMockToken')),
  })),
  notifications: jest.fn(() => ({
    onNotification: jest.fn(),
    getInitialNotification: jest.fn(),
  })),
}))

And here is my test within notifications.test.js

import { subscribeToTopic } from './notifications'
import firebase from 'react-native-firebase'

describe('notifications', () => {
  describe('topics', () => {
    const topic = 'topic'
    it('should subscribe to a topic', async () => {
      subscribeToTopic(topic)
      await expect(firebase.messaging().subscribeToTopic).toHaveBeenCalled()
    })
  })
})

Upvotes: 0

Views: 2207

Answers (1)

Lin Du
Lin Du

Reputation: 102267

Here is the solution:

notifications.ts:

import firebase from 'react-native-firebase';

export async function subscribeToTopic(topic) {
  await firebase.messaging().subscribeToTopic(topic);
}

notifications.test.ts:

import { subscribeToTopic } from './notifications';
import firebase from 'react-native-firebase';

jest.mock('react-native-firebase', () => {
  return {
    messaging: jest.fn().mockReturnThis(),
    subscribeToTopic: jest.fn()
  };
});

describe('notifications', () => {
  describe('topics', () => {
    const topic = 'topic';
    it('should subscribe to a topic', async () => {
      await subscribeToTopic(topic);
      expect(firebase.messaging().subscribeToTopic).toHaveBeenCalled();
    });
  });
});

Unit test result with 100% coverage:

 PASS  src/stackoverflow/58859904/notifications.spec.ts
  notifications
    topics
      ✓ should subscribe to a topic (5ms)

------------------|----------|----------|----------|----------|-------------------|
File              |  % Stmts | % Branch |  % Funcs |  % Lines | Uncovered Line #s |
------------------|----------|----------|----------|----------|-------------------|
All files         |      100 |      100 |      100 |      100 |                   |
 notifications.ts |      100 |      100 |      100 |      100 |                   |
------------------|----------|----------|----------|----------|-------------------|
Test Suites: 1 passed, 1 total
Tests:       1 passed, 1 total
Snapshots:   0 total
Time:        5.844s, estimated 10s

Source code: https://github.com/mrdulin/jest-codelab/tree/master/src/stackoverflow/58859904

Upvotes: 1

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