Is TDD worth it?
But wait! Before you close this tab because you got your answer, let me explain with a short story how TDD helped me to survive the project I got.
The first time I saw the code base for one of the systems I was working on, I was overwhelmed. The project had been started by a team of engineers who left before it could be completed, and now only one person remained to finish the task.
That person was me.
I knew that there were bugs in this application. I also knew that I needed to fix them as soon as possible. But when I looked at the lines of code, my eyes went crossed from trying to find where everything went wrong.
In steps TDD. Over the next few weeks, I used the TDD approach to fix all the high-priority bugs. The TDD cycle was as follows:
- First, write a failing test that confirms there is a bug in the code.
- Fix the bug. This makes the tests pass.
- Finally, refactor the code to make it better and more testable in the future.
So, yes. TDD is definitely worth your time. Here are seven reasons why:
- It helps you write better code
- You can see the design of your code before it is written
- Reduces the number of bugs in your code and improves quality assurance
- The tests are easy to read and debug when something goes wrong
- You can save time by writing fewer, more reliable lines of code
- You can safely experiment with different solutions
- It enables refactoring
In this post, I will explain all these reasons in more detail.
What is TDD?
Test-driven development, also known as TDD, is a programming technique that helps programmers break large problems into smaller ones to solve the problem systematically.
TDD is great for programmers because it helps them write cleaner code with fewer errors, which ultimately saves time in the long run.
The main drawback of TTD is that it requires some upfront work on new programs to write tests before writing any new code. However, the benefits of this process are usually worth the initial investment of time and energy!
The basic process of testing your code with TDD works in 3 steps:
- Red – The first step is to create a related test that defines the expected behavior. All this comes out to how you would expect the system to behave. The red means that the test should initially fail. The fail indicates that you have a missing functionality in your source code.
- Green – Write the smallest amount of functional code to make the tests pass. At this stage, the code doesn’t have to be production-ready. However, you want to do this step as fast as possible. The goal is to implement a code that will make the test pass. And all other tests should pass.
- Refactor – Improve the written code. In the last step, you created the code that made all the tests pass, but it may not be a clean code. That’s why the last step, refactoring, is also critical in the whole TDD process. Refactoring is when you improve your code without changing its external behavior. It is often done by applying small individual changes to your code, which are small, safe, and reversible.
Many developers see TDD practice as tedious, but there are plenty of reasons why TDD is worth your time.
#1 TDD helps you write better code
The TDD methodology is a design approach that helps programmers write software code that they can easily change. All code changes should be tested before being added to the codebase. TDD forces you to do that.
TDD makes it easier to maintain code and also find bugs earlier in the process, saving time and money in the long run.
One of the main benefits of using TDD is creating quality code with fewer errors while also designing better code for future use.
Some skeptics of TDD argue that it takes more time than not following such practices because developers must add extra code to write tests. However, TDD code tends to be easier to code and more organized than code written without the help of TDD.
#2 You can see the design of your code before it is written
Not only does TDD ensure you’re writing code that works, but it also helps you to think about how you will code the application long before you write a single line of code. TDD helps you to design better-looking code.
Many experienced developers say that unit tests force them to think about how they will structure and what components they will need for new projects. This helps limit the number of bad decisions they make and often gets them to the final product faster than not using unit tests.
#3 TDD reduces the number of bugs in your code and improves quality assurance
TDD methodology has been proven to reduce the number of errors in a program by finding defects early in the development cycle.
Unit testing helps programmers find mistakes before they have been released to users. It allows them to fix the error before it is seen by consumers. It also improves quality assurance for programmers and unit testers. Unit tests improve the codebase’s overall quality by catching bugs early on and increasing code coverage with efficient unit tests.
Test driven development decreases the need for manual testing. Every test case developers write means a single scenario less that the QA team needs to check.
#4 The tests are easy to read and debug when something goes wrong
If you use continuous integration to merge code changes, a failing automated test will immediately warn you about the issue. You can then quickly find the problem and avoid wasting time.
#5 You can save time by writing fewer more reliable lines of code
The TDD philosophy is this: code quality over code quantity.
It can take longer to write test cases than it would be writing the actual lines of code. However, writing test cases makes writing the actual lines of code much faster because you know what exactly needs to be written and how it should work. Once all tests passes, you are done with your work.
You might end up with a lot more code in total, but around half of the amount is the tests. This means that your development time stays roughly the same. The only difference now is that you spend a lot more time testing. Which is always a big plus.
#6 You can safely experiment with different solutions
TDD helps you to quickly and safely experiment with alternative solutions. If you’re writing tests early on in the development stages, such as writing a single test case that fails, then writing code that passes it, you can try out different solution paths without fear of breaking something.
The tests you have will tell you if you make a mistake.
Compare this with a traditional development process. In those circumstances, you don’t have as many tests as with TDD. This means you need to carefully make every change and pray that you haven’t broken anything. Of course, those changes often introduce additional technical debt to your code base.
#7 It enables refactoring
TDD enables refactoring because by writing tests first, you can check that your changes didn’t break anything. I’ve found this to be especially helpful when working with legacy code. You can refactor without worrying about breaking something. Just write the tests first and fix the errors as you go along.
When you make changes or refactoring code, you want to make sure that the expected behavior stays the same. Therefore, when you perform a refactor but an automated test fails, the failing test will pinpoint the issue with your refactoring.
So yes, TDD is worth it.
It helps you to quickly and safely experiment with different solutions. In addition, unit tests contribute to improving the overall quality of the codebase by catching bugs early on and increasing code coverage with efficient unit tests.
Test driven development decreases the need for manual testing. Every test case developers write means a single scenario less that the QA team needs to check. And that’s the ultimate benefit: automation over tedious manual traditional testing.