What is TDD, and How Does it Work? - FeRHeDio

What is TDD?

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

See me solving the well known FizzBuzz Kata applying TDD here -> How to TDD: FizzBuzz Kata with Swift

At first it may seems to not make any sense, since we don’t have any of the 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 it.

How is the TDD Process

The process is iterative, consisting of just this 3 steps:

Red State 🔴 – Write a Failing Test: The first step here is when 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. This puts you in the Red State.
Green State 🟢 – Make the test pass: Your goal here is to make the test pass writing the least amount of code required to make the failing test pass, and nothing more.
Here is the hard stuff because discipline is needed to avoid keep going and just write only the minimum to make the test pass.
Refactor – R: After making the test pass, you can and need to refine your code. This is the “Refactor” phase. It’s an opportunity to enhance the design, improve the performance, make it cleaner, remove the duplication and ensure your code is maintainable. You may find some hardcoding values that made the test pass, and it’s ok, but at some point you need to remove it, here is is your opportunity to get rid of that and make your code better.
As any of the other stages, you won’t skip any of those.

After this, you start anew, following the 🔴-Red – 🟢-Green – R-Refactor cycle once again.

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.

Check out Uncle Bob’s famous TDD cycle post -> https://blog.cleancoder.com/uncle-bob/2014/12/17/TheCyclesOfTDD.html

Benefits of TDD

Improved Code Quality: Applying Test Driven Development, 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.

Conclusion

In conclusion, Test-Driven Development (TDD) isn’t just a development methodology; it’s a mindset, a way to develop ensuring your code is robust, maintainable, and reliable at every step of the way.

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.

Remember to start small, write little tests here and there, 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!