How to test that chrome.runtime.sendMessage is being called?

[clarkbw]

How to test that chrome.runtime.sendMessage is being called?

[clarkbw]

Can you link me to your repo?

[clarkbw]

I would assume it’s not setup correctly, can you check those steps in the readme?

[davesag]

Can you link me to your repo?

Sorry it's a closed-source project but I will see if I can get that changed. I'll recheck the readme.

[davesag]

I would assume it’s not setup correctly, can you check those steps in the readme?

I have rechecked the readme and there is nothing in it that I can see with specific set up steps for testing chrome.runtime.sendMessage. However I have now got this to work.

Here's the full source of my src/messaging/utils/send.js

/**
 *  A promisified version of the chrome sendMessage function.
 *
 *  @param the message to send.
 *  @returns a promise that resolves with the message response.
 */
const send = async msg =>
  new Promise(resolve =>
    chrome.runtime.sendMessage(msg, response => {
      if (chrome.runtime.lastError) {
        console.error(chrome.runtime.lastError.message);
      }
      resolve(response);
    })
  );

export default send;

and here's the now working test

import send from 'messaging/utils/send';

const message = 'some message';

const cleanup = () => {
  chrome.runtime.sendMessage.clearMocks();
  chrome.runtime.lastError = undefined;
};

describe('with no error', () => {
  beforeAll(async () => {
    chrome.runtime.sendMessage = jest.fn((msg, callback) => callback(msg));
    await send(message);
  })

  afterAll(cleanup);

  it('called chrome.runtime.sendMessage with the message', () => {
    expect(chrome.runtime.sendMessage).toHaveBeenCalledWith(
      message,
      expect.any(Function)
    );
  });
})

describe('with an error', () => {
  const error = new Error('oops');

  beforeAll(async () => {
    chrome.runtime.sendMessage = jest.fn((msg, callback) => callback(msg));
    chrome.runtime.lastError = error;
    await send(message);
  })

  afterAll(cleanup);

  it('called chrome.runtime.sendMessage with the message', () => {
    expect(chrome.runtime.sendMessage).toHaveBeenCalledWith(
      message,
      expect.any(Function)
    );
  });

  it('called logger.error', () => {
    expect(console.error).toHaveBeenCalledWith(error.message);
  })
})

[clarkbw]

I was wondering how you were using the setup, seen here: https://github.com/clarkbw/jest-webextension-mock#use-setup-file

[davesag]

I have a jest.init.js file

import 'core-js/stable';
import 'regenerator-runtime/runtime';
import 'jest-webextension-mock';

global.fetch = require('jest-fetch-mock');

global.console = {
  log: console.log,
  error: jest.fn(),
  warn: jest.fn(),
  info: jest.fn(),
  debug: jest.fn()
};