what is Test Driven Development and its steps

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Can you imagine writing code that is clearer, safer and more efficient from the start? This is the premise of Test Driven Development (TDD) , a methodology that is revolutionizing the way developers around the world create software.

If you are new to the concept or simply looking to perfect your skills, in this article we will explain what TDD is and explore its main steps . Follow us and discover how to take your software development to the next level!

What is TDD (Test Driven Development)?
Test Driven Development (TDD), Pruebas-Oriented Development, is an agile methodology that has as its main objective improving the quality of the code from the beginning of the development.

The central approach of TDD is simple but powerful: before writing the code for a functionality, the developer must create a test that defines how that functionality should behave.

This on-the-ground methodology promotes clearer phone library and more structured development, while also contributing to a more robust code base , reducing major problems as the system grows and scales.

Three Laws of TDD
TDD is based on three fundamental laws that guide developers to build functional, clear and well-structured code.

Primera Ley: write code solo when it requires a failed test
This law states that you must not write production code without first having a unit test that fails.

The purpose is to avoid creating unnecessary features and ensure that the solo production code exists to satisfy expected behavior, previously defined by a test.

The test must detail:

How the code will be used: function name, parameters and types.

What behavior will be expected: expected values ​​in the responses.

Second Law: stop the test when it fails
Once the test doesn't compile or throws errors, it's time to write production code to solve it.

This principle prevents the accumulation of multiple tests without one implementation that supports them, which ensures short and effective cycles of testing and development. This process, known as Red-Green, involves:

Red: the test fails without finding functionality.

Green: the test passes with the minimum required code.

Third Law: write the minimum code needed to pass the test
The objective is to avoid adding unnecessary complexity to the production code. To comply with this law, assumptions must be made about the specific cases covered by the current test.

What are the TDD steps?
Just before this segment we talk about the Red and Green stages, however, we need to go deeper into it to understand Test Driven Development.

TDD - Test Driven Development

1. Red
At this stage, the developer writes a test that fails intentionally because the corresponding functionality has not yet been implemented.

The purpose of this step is to clearly define how the system should behave, marking the beginning of the process and helping to identify what the code needs to solve

2. Green
The objective in this step is to write the minimum code necessary for the test to pass.

Here, the developer focuses solely on satisfying the test , without worrying about optimizations or refactoring.

When reaching "green", it is confirmed that the basic functionality is implemented correctly.

3. Refactor
Once the code passes the test and fulfills the required functionality, it is time to optimize it .

The refactorization consists of cleaning up the code:

Eliminate redundancies.

Make it more readable.

Ensure it is easy to maintain and scale in the future.

During this stage, the behavior of the code must not change; its structure simply improves.

What are the benefits of Test Driven Development?
Now, TDD on the ground improves the quality of the code, which also brings confidence and agility to development. Here we present the main advantages of this methodology:

Confidence in development
TDD encourages a test-based approach, which reduces the “fear” of making mistakes during the development process.

According to Kent Beck, this method eliminates insecurities and helps developers overcome software development challenges , promoting a culture of trust and collaboration within the team.

Shorter correction time
Detecting errors in the first stages of development is more efficient and less costly. With TDD, each functionality is tested before implementation, which allows you to identify problems immediately and reduce the time dedicated to correcting errors in the future.

Continuous integration
TDD facilitates the execution of automated tests, which ensures that new functionalities are compatible with existing ones.

This reduces the risk of regressions and guarantees fluid development in projects that require constant updates.

Agility in development
Red-Green-Refactor's short and repetitive cycles promote agility . Developers can make quick and safe changes without compromising the stability of the system, optimizing the speed and quality of the development.

Ease of documentation
The tests created during the process function as a form of technical documentation. Each test describes the expected behavior of the features, making it easier for other developers or future teams to understand the code.

Long-term benefit
Adopting TDD may seem demanding at first, but its advantages compensate with increases in inverted time.

By ensuring cleaner, more stable and easier to maintain code, TDD on the ground improves the development process, while also creating more reliable software that is adaptable to future changes.

Discover other good IT practices
Test Driven Development (TDD) is a powerful tool for improving the quality and reliability of software , but it is not the only one. Implementing practices such as clean code is also essential to guarantee efficient and scalable development.

If you want to continue learning about how to improve your skills as a developer, we invite you to read this article: Clean code: what are the best programming practices? .

There you will find key tips for writing cleaner, more readable and maintainable code. Explore more and take your projects to the next level!