7 Awesome Test Driven Development Advantages

Tired of testing?

You’re not alone.

Lots of developers get stuck in a rut and stop testing, but this is a huge mistake. Testing can help you write cleaner code and make it more maintainable for future changes. Testing also helps you find bugs sooner, so you don’t waste time trying to fix something that doesn’t even need fixing. Finally, test-driven development takes the guesswork out of whether or not your code is working correctly, making it an excellent methodology for software developers.

The biggest advantages of test-driven development are:

  • Better code quality
  • Testing and debugging are built into the process
  • Better project documentation
  • Better productivity
  • High test coverage
  • It’s easier to refactor
  • Quality assurance is less expensive

Let’s explore how test-driven development can help you become a better developer.

What is TDD?

Unit testing is an integral part of programming. The fewer bugs in your code, the better. Test-driven development is a type of development where you write tests first, then the actual code. You write the production code after you see a failing test. Your objective is to make the test pass by implementing the necessary changes in the code.

The process is typically designed around small testable scenarios called test cases. The TDD cycle proceeds in the following way:

  1. The developer writes a new test case, a new automated test.
  2. Then he produces the desired functionality by implementing that test case.
  3. Re-runs the test to confirm that it passes.
  4. The last step is to refactor and improve the code or tests.

Test-driven development is an excellent way to develop software because it incorporates a testing cycle into the normal process of writing production code.

And it has many advantages.

1. Better code quality

Test driven development is a way of writing your code where you write tests before writing the actual code. Instead of writing a big monstrous class, you are forced to write a small and concise software class. In other words, you are only developing the class to meet the needs of that specific unit test. The classes are also easier to maintain because you only need to focus on one class and not many.

Another reason why the code quality is better is that you first figure out the interface and the implementation comes after that.

What does that mean? Let’s say you want to create a new method to implement a feature. You start with a unit test, and in it, you design how you want the call to that method to look. Even if the method does not exist, you can figure out the entry point first, then deal with the implementation details. The traditional development does this sometimes in reverse: you create a bunch of code, then figure out how to call it from the rest of the system.

2. Testing and debugging are built into the process

By writing tests before you write the code, you know what your code is supposed to do and the possible errors it might have. If a new issue is discovered, it’s caught at an early stage.

In the same way, testing your software ensures that it behaves as intended, which prevents unforeseen issues.

When you develop your code using TDD, you won’t have to spend a lot of time debugging issues when something goes wrong. Instead, if you have everything covered with the tests, then a failing test will tell you where exactly the problem lies.

3. Better project documentation

If you work on a bigger project, it’s difficult to understand all the written code. It’s also challenging to make changes to that code. If you use the TDD methodology, you have living documentation of your code because you can always run the automated unit tests to understand the existing code and use tests as a guide to modify it.

Using tests as documentation is beneficial for teams who work on the same code base because they can all see how the code is intended to work.

So, the next time when you need documentation to better understand the code, just look at the tests for more information about usage and meaning. You will also find that the tests contain the requirements that have been already implemented. This can provide help in defining future development.

4. Better productivity

TDD can also make you more productive. What is the reason for that? When you’re only testing the current function that you’re working on, you won’t get distracted by thinking of the other parts of the system.

You focus on one thing at a time. Write a failing test. Ok, after that, think about how to write the code that will make the test pass. Finally, think about how you can improve and refactor the code.

This way of working avoids implementing more code in the system that is unnecessary for the current moment. Besides, the code you write in this manner is more modular and better structured.

5. High test coverage

The most significant side-effect of a TDD is high test coverage. Test coverage is the percentage of the code that was actually executed by tests. This makes sense since you only write the code that makes the test turn green.

Higher test coverage means that there is less chance that any new code will break. If it doesn’t break, then you can confidentially deploy the code to production.

It is also advisable to run the tests you have as often as possible. And run them automatically using a continuous integration/continuous delivery tool.

6. It’s easier to refactor

Refactoring is the process of modifying the code to make it cleaner. In addition, refactoring keeps the code modular and reusable.

What’s more, the refactoring process is actually necessary when you practice the TDD approach. The code you write to satisfy the test can often be a duplication or contain other code smells. That’s why the final step in the TDD process is refactoring. With refactoring, you examine whether your functional code and test code meet the necessary code standards. If it doesn’t, improve it until you have a clean code. The test suite is your safety net.

A word of caution here: make sure you don’t make your tests too brittle. Often while writing unit tests, developers tend to use mocks. Sometimes they take it too far, so it becomes harder to change the code. With too many mocks, even a tiny refactoring causes a test to fail. The failure, in those cases, doesn’t necessarily mean that you introduced a bug. Instead, it can mean that the test was checking the actual implementation details and not the observed behavior.

7. Quality assurance is less expensive

Test driven development is becoming a popular way of ensuring quality in software. It can be a time-consuming process, but in the end, it provides excellent results.

It also decreases the cost of quality assurance. Quality assurance can be less expensive because there is less wasted time due to manual software testing. With TDD, you perform testing throughout the development process. The testing phase doesn’t come after you finish with the development. Instead, the testing and development happen at the same time.

But it would be best if you still have QA engineers. The QA team can spend less time on repetitive manual traditional testing and more on writing automated UI tests.


In this blog post, I have outlined the benefits of test-driven development. It not only provides living code documentation but also improves code quality and code coverage.

I hope this blog post was a helpful tool in deciding whether to use TDD. If you need more information on how to do the TDD, check out the full article about test-driven development.

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