How do I stub "chrome-launcher" with sinon?

Hello, thanks for the hard work on this library, it is really great.

I’ve got a module that exports the following function (among many others)

import puppeteer from 'puppeteer-core';
import * as ChromeLauncher from 'chrome-launcher';
import fetch from 'node-fetch';

export const launchBrowser = async (options = {}) => 
  // Launches Chrome
  const chrome = await ChromeLauncher.launch(options);
  // Gets the port Chrome is running on
  options.port = chrome.port;
  // Connect puppeteer to the running Chrome instance
  const response = await fetch(`http://localhost:${options.port}/json/version`);
  const { webSocketDebuggerUrl } = await response.json();
  return puppeteer.connect({ browserWSEndpoint: webSocketDebuggerUrl });
};

I’m using mocha in conjunction with chai and sinon to test it. I’ve got the following test where I’m calling import * as ChromeLauncher from 'chrome-launcher' before the module to test so that I can apply the stub correctly.

import sinon from 'sinon';
import * as ChromeLauncher from 'chrome-launcher';
import { launchBrowser } from '...';

describe('something', () => {
  const sandbox = sinon.createSandbox();

  afterEach(() => sandbox.restore());

  it('should do something', async () => {
      const chrome = {
        port: '3434'
      };
      sandbox.stub(chromeLauncher, 'launch').resolves(chrome);

      ... ... ...

      await launchBrowser(options);

      sandbox.assert.calledOnceWithExactly(ChromeLauncher.launch, options);
    });
});

As you can see, I’m using sandbox.stub(chromeLauncher, 'launch').resolves(chrome) to decorate the launch function and resolve with a fake chrome object.

Unfortunately it doesn’t work, and it calls the real chrome-launcher.

My question is, how can I stub the launch function properly? Do you provide mocks ready to use?

Thanks, hope you’ve got all the details you need.

[westy92]

@simonespa I was able to use proxyquire to mock chrome-launcher: https://github.com/westy92/html-pdf-chrome/pull/297

[simonespa]

Hi @westy92 @paulirish is this issue fixed then? Can we say it is now possible to mock the chrome-launcher module with sinon?

Thanks both 😄