dev javascript, tdd, unit_testing

There are so many names of tools and frameworks are flying around in JavaScript if you’re a beginner it’s easy to get lost.

First things first: Identify what’s what

Basically we need the following key components to write and run unit tests:

  • Assertions: We run a method in subject under test and compare the result with some known expected value
  • Mocking: We need to mock the external dependencies (network services, database, file system etc) so that we can reliably test subject under test and the tests can run everywhere and without requiring any credentials or permissions.
  • Test runner: Our test is some block of code. Something needs to make sense of the unit tests we wrote, execute them and show the results (fail/pass)

Choosing the weapons: Mocha and Chai

In this example I’m going to use Mocha as my test runner and Chai as my assertion library.

They can simply be installed via NPM:

npm install --save-dev chai

To be able use Mocha in the Integrated Terminal inside Visual Studio we have to install Mocha as a global package:

npm install -g mocha

To put these to test I created this simple Maths service that calculates the factorial of an integer.

module.exports = class MathsService {
    factorial(num) {
        if (num < 0) 
            return -1;
        else if (num == 0) 
            return 1;
        else {
            return (num * this.factorial(num - 1));
        }
    }
};

And my unit test to test this method looks like this:

const MathsService = require('../maths-service.js');
const chai = require('chai');
const expect = chai.expect; 

describe('Factorial', function() {
    it('factorial should return correct value', function() {
        const mathsService = new MathsService();
    
        expect(mathsService.factorial(-1)).to.equal(-1);
        expect(mathsService.factorial(0)).to.equal(1);
        expect(mathsService.factorial(1)).to.equal(1);
        expect(mathsService.factorial(3)).to.equal(6);
        expect(mathsService.factorial(5)).to.equal(120);
    });
});

Chai supports 3 styles:

  • Should
  • Expect
  • Assert

They all server the same purpose so it’s just a matter of taste at the end of the day. For this demo I used expect style.

By default Mocha searches test folder. So you can run mocha without parameters if you put your tests under test folder or you can specify the folder. For example, in the screenshot below I moved the test to the root folder and entered “mocha .” and that worked fine as well.

Conclusion

In this post I want to show the very basics of unit testing in JavaScript just enough to see a passing test. In future posts I’ll build on this and explore other frameworks and other aspects of TDD.

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linux macbook, ubuntu

This is my old MacBook Mid 2009. It was sitting in the closet for so long I thought I could invent some purpose and use it before it finally dies. Looks like latest macOS version don’t even support this device so I thought maybe I could use it as a learning tool for Ubuntu.

Since SSDs are so cheap these days I just decided to keep the old macOS drive as backup and install Ubuntu on one of these babies:

I think around £18 is a small price to pay for a brand new SSD so went with it.

Installing Ubuntu

  1. Download the ISO here

  2. Burn the ISO to a USB Drive. Instead of installing extra software I followed this guide: Making a Kali Bootable USB Drive. It’s for Kali Linux but this bit works for burning any Linux distro.
  3. For the rest follow the steps here starting with Step 9

And after the installation this is what my MacBook looks like:

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hobbymisc productivity, apple_watch, alexa, philips_hue, iot

My #1 rule for productivity is “No Snoozing!”. If you snooze, it means you are late for everything you planned to do and that is a terrible way to start your day. This post is about a few tools, tips and techniques I use to prevent snoozing.

Tip #1: Sleep well

This is generally easier said done but there’s no way around it. You MUST get enough sleep. Otherwise, sooner or later your will power will get weaker and weaker. Eventually you’ll succumb to the sweet temptation of more sleep.

Tip #2: Place the alarm away from your bed

This way when your alarm (most likely your phone) goes off you have to make a deliberate attempt to get up and turn it off. If you have to get out of the bed you’re more likely to not to get back to it straight away.

Tip #3: Use multiple alarms with different sounds

It gets easier to wake up if you can surprise yourself! Human beings are so good at adapting to every condition we very easily start getting used and ignore the same alarm sound going off at the exact same time every day. I find it useful to change the alarm times and sounds every now and then.

Tip #4: Use Apple Watch

After Apple Watch Series 4 was released I got myself one.

I’m not sure if it’s worth the cost but when it comes to waking up a little vibration on your wrist can do miracles apparently!

When you have it pair with your iPhone, by default you can stop the alarms from your watch. This may be a nice convenience feature in some cases, but when it comes to waking up we are trying to make it as hard as possible for ourselves to turn the alarms off.

My trick is:

First I disable “Push alerts from iPhone” in the Watch app.

Then I create a separate alarm on watch for the same time.

This way I get 2 alarms at the same time. It’s easy to stop the watch as it’s within my arm’s reach. While the haptic feedback of the watch wakes me up the alarm on the phone also goes off. Now I have to physically get out of the bed to stop that one as well.

Tip #5: Use Alexa

Another gizmo to set an alarm is Alexa but you can do much more than just that with Routines.

Tip #5.1: Play a playlist

This tip requires Spotify Premium subscription.

First, create yourself a nice, loud and heavy playlist of “waking up” music. I prefer energetic Heavy Metal songs from Lamb of God and Slayer. The trick here is to play a random song every morning. Similar to Tip #3, the same song every morning becomes very boring very quickly. But having a random one keeps you surprised every morning. I use this command to play my playlist in shuffle mode:

Shuffle Playlist '{Playlist name}'

Tip #5.2: Turn the lights on

A good sleep tip is to keep your bedroom as dark as possible. That’s why I have all black curtains in my room and it’s quite dark. The downside is it’s so good for sleep it makes waking up even harder!

That’s why I bought myself a Philips Hue smart bulb and as part of my waking up routine Alexa turns it on along with playing the Spotify playlist.

This is what my routine looks like:

Conclusion

For me snoozing is a cardinal sin so I’m always on the lookout for improving my arsenal to fight against snoozing. Hope you find something useful in this post too. If you have tips on your own feel free to leave a comment.

Resources