Creating Random Data on my Lunch Break…

A few days ago I read a great post by Alan Richardson called “How to write a simple random test data sentence generator” and i loved it, it’s exactly what I try and do all the time. In my current context, data is king, without data flowing through our service we effectively have no service. While testing stories, I create tools that do loads of little things but I have a selection of ones that create specific test data. Now, I’m not a developer, I don’t have any sort of development background but what I am, is an inquisitive learner.

I love writing code, not because I’ve been made too or I’ve been told too by my company so that I can automate all the things, I do it because it’s fun! I get a massive sense of achievement when I’ve had an idea for a tool, wrote some code and it’s worked!! It’s not the best looking and most efficient code but it’s my code and i’m proud of it!

So where was I, the random data generator – I read Alan’s post just before lunch and just before i tucked into my food i wrote a very basic app that spit’s out random data. All in all it took me less than 5 mins, it was done as a kind of exercise to prove that absolutely anyone can code something that creates test data. Don’t be afraid of just giving something a go, you might actually surprise yourself!

*This is wrote using Node.js but there’s probably tons of modules and libraries in your preferred language that will allow you to do the same thing*

We need to start somewhere…

In order to get your hands on this random data you’re going to have to download Node.js it won’t take very long and it’s so worth it, not only for this but for many other awesome things that you can create using Node.

Once you have it installed, type node -v into a command prompt or terminal. You should be presented with the current version that you have on your machine. If you’re not seeing the version, don’t panic, you might have to add the node directory to the path environment variable. You’ll find loads of step by step guides for this if you Google it.

node -v


Let’s do the code part!

So first things first, we need to create a new directory for your new and wonderful data generator to live. Open a command prompt or terminal (you may have one still open) and enter the following commands, as seen below. It’s entirely up to you what the root directory should be, after all, you’re doing this on your own machine.

mkdir random_data_generator
cd random_data_generator

*You don’t have to create this but I just like creating it so that i can give the app to other people*

Next, we need to create the package.json file this is the config file for your node app, it lists all the dependencies that you have in your project and also a bunch of other stuff you may need to add, as the app starts growing legs. You can read all about what this file is and what it does here but for now, we’ll crack on…

In the terminal enter the following and press Enter. Press enter through all the questions and type Y or Yes at the end.

npm init

Now we have that json file created we need to bring in the node module that’s going to do all the leg work for us and create the random data. Casual is a great helper module that rapidly speeds up the process of creating random data. There are a couple more great modules out there that do the same thing, like Chance.js and Faker.js but were going to use Casual this time because it’s the first one I thought of and I’m writing this post so that’s what you’ve got!

Install Casual by entering the following command into your terminal and pressing Enter. The –save in the command adds this module to the packages.json file, honestly, go and have a look if you don’t believe me.

npm install --save casual

When it has finished installing the module, leave the terminal open as you’re going to need it in a few mins.

Create a new file with your favorite text editor (Sublime Text, Notepad++ etc.) and save this in the new random_data_generator directory. For this example, I’ve named the file data.js but you can choose a name that’s more relevant to you.

In the file add the following code…

 // Dependencies
var casual = require('casual');

// Using the module to create random data
var number = casual.array_of_digits(n = 4);

var name = casual.first_name;

// Log the result

There are a couple of things going on here and I’ll explain (probably really poorly) what they are, so starting from the top, the first line after the comment brings in the Casual module so that we can use all of that goodness. Next, in the middle section, we’re using a couple of the in-built Casual functions that will create the random data and assigning these to the variables. Finally, we are just logging the output in the console. Very basic and extremely simple.

Using the terminal that you previously opened, type node data.js and press Enter to run the command. If everything has been setup correctly, you will be presented with some random data. It’s as easy as that.



If you create another file in the same directory and save this one as user.js I can show you a simple way of creating a set of basic user data. Add the following code below to the file and hit save again. To get an idea about what you can do with the Casual module, check out the documentation.

// Dependencies
var casual = require('casual');

// Custom Data Set

var password = '#A#B#C#D#E#F#';

casual.define('user', function() {
 return {
 Firstname: casual.first_name,
 Lastname: casual.last_name,
 Password: casual.numerify(password)

// Write the result to the console


What this file is doing is creating a data set, defined and configured to your needs. Using the define function of Casual you can package this all together in a lovely little ball and do what ever you like with the output. On this occasion, I’m just logging it out to the console again. There are a few other things happening in this data, i’m using a couple of other inbuilt functions to create a different (very rubbish) password.

In the terminal type node user.js and press Enter to run the command. There you go…some more data for you!


Where do you go from here…

As you can tell this is very basic and the only thing it really does is print data out to the console – Not that helpful. This was only ever a 5 min task to quickly knock something together, we can expand this out to push the data to a certain file format that your system uses or feed the data into an already established test tool that you have been manually creating random data sets for, etc etc….I like the idea of creating Json files that can be added to apps like Bug Magnet so that you have the data there for you, while you’re doing an exploratory session.

We are only ever limited by our own imagination so it’s entirely up to you where you go from here but i’d love to hear about it so drop me a message!

*If you really can’t be bothered to create a tool yourself – Just Google “Random Data Generator” there’s bloody tons of them knocking about!!

Cheers for reading!

I now have a follow on post where you can put some of this beautiful data to good use…



One thought on “Creating Random Data on my Lunch Break…

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