What is TDD, and How Does it Work?

Posted on by Fernando Putallaz

Test-Driven Development (TDD) is a software development methodology that revolves around the creation of automated tests before writing the actual code.

At first may not make any sense since we don’t have any so called “production code”, or the code that is needed to make your system work. But very soon you’ll realize that this methodology provides a lot of benefits to the quality of your code and the confidence you’ll have before shipping.

The process is iterative, consisting of the following stages:

  1. 🔴 – Write a Failing Test (Red): In this step, you create a test that defines the behavior you want to implement. This test will inevitably fail since you haven’t written any code yet.
  2. 🟢 – Write the Minimum Code that make the test pass (Green): Your goal here is to write the least amount of code required to make the failing test pass, and nothing more.
  3. R – Refactor: After making the test pass, you can refine your code. This is the “Refactor” phase. It’s an opportunity to enhance the design, improve performance, and ensure your code is maintainable. You may find some duplication taking place during the green phase, here is your opportunity to get rid of the duplication and make your code better, don’t ever skip this step.

After this, you start anew, following the 🔴-Red – 🟢-Green – R-Refactor cycle. It’s imperative to keep in mind that TDD is an iterative process, in stark contrast to the conventional coding approach. In the usual coding process, we frequently rush through, typing code, manually testing it on the screen, and then moving forward without much consideration, only to later discover that our code may be incomplete, riddled with bugs, or, even worse, causing disruptions in other parts of the system.

Benefits of TDD

  • Improved Code Quality: TDD encourages a more thoughtful approach to coding. By writing tests first, you ensure that your code is well-structured and functional.
  • Reduced Debugging Time: With a suite of tests, you can catch and fix issues early in the development process, reducing the time spent on debugging.
  • Faster Development: Surprisingly, TDD often leads to faster development because it forces you to focus on one piece of functionality at a time.
  • Confidence in Changes: When you make changes or add new features, you can run your tests to ensure that existing functionality remains intact. This confidence is invaluable as your project grows.

In conclusion, Test-Driven Development (TDD) isn’t just a development methodology; it’s a mindset, a way to ensure your code is robust, maintainable, and reliable.

With TDD, you’ll craft code with confidence, spot and squash bugs early, and create software that stands the test of time.

So, whether you’re a seasoned programmer or just starting out, embrace TDD in your Swift development projects. Start small, write tests that matter, and let them guide your code. Your future self, your team, and your users will thank you.

Now, it’s your turn. Give TDD a try, and let it transform the way you approach development. As always, keep coding, keep testing, and keep striving for excellence in your craft.

-> 🔴 -> 🟢 -> R -> 💪

Thanks for reading!