How to Write Unit Tests

And how to organize them properly

How many times did you write code and later found out, that it does not work like expected? Or even worse, it worked just fine until you changed something you thought was unrelated and bam… your code became a buggy mess? Well, maybe not a mess, but it did not work correctly anymore. When you changed something, you introduced a bug. If you want to catch bugs early and ensure stable code, you have to start testing it. And the very first step are unit tests.

TL;DR
Unit testing is an essential practice in software development that ensures the quality and reliability of code. By isolating specific units and subjecting them to different test scenarios, developers can detect bugs, verify expected behavior, and maintain code stability. In this article, I’ll explain the fundamentals of unit testing using Ava.js and Sinon.js. I’ll also try to explain best practices for structuring your unit tests effectively.

The Theory with a little bit of practice

What is Unit Testing? Unit testing means examining isolated units of code to validate that it works correctly. These units are typically functions that perform tasks within an application. Unit tests are written to verify the behavior of these units and ensure that they work as expected.