onion/test

TL;DR

Copy the file .env-template in .env and fill up the missing keys.

$ npm install
$ npm run tunnel
$ npm test && git commit

Welcome to our test suite, let me be your guide

Dear reader, first of all thanks for taking your time reading this document. The purpose of this document is to give you an overview on what we want to test and how we are doing it.

How it works (bird's-eye view)

You will notice that the setup is a bit convoluted. This section will explain you why. Testing single functions in JavaScript is not that hard (if you don't need to interact with the DOM), and can be easily achieved using frameworks like Mocha. Integration and cross browser testing is, on the other side, a huge PITA. Moreover, "browser testing" includes also "mobile browser testing". On the top of that the same browser (type and version) can behave in a different way on different operating systems.

To achieve that you can have your own cluster of machines with different operating systems and browsers or, if you don't want to spend the rest of your life configuring an average of 100 browsers for each different operating system, you can pay someone else to do that. Check out this article if you want to know why using Selenium Grid is better than a DIY approach.

We decided to use saucelabs cloud (they support over 700 combinations of operating systems and browsers) to run our tests.

Components and tools

Right now we are just running the test locally, so no Continuous Integration™.

The components involved are:

• Selenium WebDriver: it's a library that can control a browser. You can use the WebDriver to load new URLs, click around, fill out forms, submit forms etc. It's basically a way to control remotely a browser. The protocol (language agnostic) is called JsonWire, wd wraps it and gives you a nice API you can use in JavaScript. There are other implementations in Python, PHP, Java, etc. Also, a WebDriver can be initialized with a list of desired capabilities describing which features (like the platform, browser name and version) you want to use to run your tests.

• Selenium Grid: it's the controller for the cluster of machines/devices that can run browsers. Selenium Grid is able to scale by distributing tests on several machines, manage multiple environments from a central point, making it easy to run the tests against a vast combination of browsers / OS, minimize the maintenance time for the grid by allowing you to implement custom hooks to leverage virtual infrastructure for instance.

• Saucelabs: a private company providing a cluster to run your tests on over 700 combinations of browsers/operating systems. (They do other things, check out their websites).

• SauceConnect: is a Java software by Saucelabs to connect to your localhost to test the application. There is also a Node.js wrapper sauce-connect-launcher, so you can use it programmatically within your code for tests. Please note that this module is just a wrapper around the actual software. Running npm install should install the additional Java software as well.

On the JavaScript side, we use:

• Mocha: a test framework running on Node.js.

• chai: a BDD/TDD assertion library for node that can be paired with any javascript testing framework.

• chaiAsPromised: an extension for Chai with a fluent language for asserting facts about promises. The extension is actually quite cool, we can do assertions on promises without writing callbacks but just chaining operators. Check out their README on GitHub to see an example.

• dotenv: a super nice package to load environment variables from .env into process.env.

How to set up your .env config file

In the root of this repository there is a file called .env-template. Create a copy and call it .env. This file will store some values we need to connect to Saucelabs.

There are two values to be set:

• SAUCE_ACCESS_KEY
• SAUCE_USERNAME

The two keys are the default ones used by many products related to Saucelabs. This allow us to keep the configuration fairly straightforward and simple.

After logging in to https://saucelabs.com/, you can find your api key under the My Account. Copy paste the value in your .env file.

Anatomy of a test

First, you need to learn how Mocha works. Brew a coffee (or tea, if coffee is not your cup of tea), sit down and read the docs.

Done? Great, let's move on and analyze how a test is written.

From a very high level, the flow of a test is the following:

1. load a page with a specific URL
2. do something on the page (click a button, submit a form, etc.)
3. maybe wait some seconds, or wait if something has changed
4. check if the new page contains some text you expect to be there

This is not set in stone, so go crazy if you want. But keep in mind that we have a one page application, there might be some gotchas on how to wait for stuff to happen. I suggest you to read the section Wait for something to understand better which tools you have to solve this problem. Again, take a look to the wd implementation of the JsonWire protocol to know all the methods you can use to control the browser.

Import the libraries we need.

'use strict';

require('dotenv').load();

const wd = require('wd');
const chai = require('chai');
const chaiAsPromised = require('chai-as-promised');

Set up chai to use chaiAsPromised.

chai.use(chaiAsPromised);
chai.should();

browser is the main object to interact with Saucelab "real" browsers. We will use this object a lot. It allow us to load pages, click around, check if a specific text is present etc.

describe('Login logs users in', function() {
    let browser;

Create the driver to control the browser.

    before(function() {
        browser = wd.promiseChainRemote('ondemand.saucelabs.com', 80);
        return browser.init({ browserName: 'chrome' });
    });

This function will be executed before each it function. Here we point the browser to a specific URL.

    beforeEach(function() {
        return browser.get('http://www.ascribe.ninja/app/login');
    });

While this function will be executed after each it function. quit will destroy the browser session.

    after(function() {
        return browser.quit();
    });

The actual test. We query the browser object to get the title of the page. Note that .title() returns a promise but, since we are using chaiAsPromised, we have some syntactic sugar to handle the promise in line, without writing new functions.

    it('should contain "Log in" in the title', function() {
        return browser.title().should.become('Log in');
    });

});

How to run the test suite

To run the tests, type:

$ mocha

By default the test suite runs on http://www.localhost.com:3000/, if you want to change the URL, change the APP_URL env variable.

How to have fun

Try this!

$ mocha -R nyan