Benefits of Test-Driven Development



October 20, 2023

Test-driven development (TDD) is a popular software development technique in which software developers write automated tests that first verify the functionality of their software, and then they write the code to pass the test.

The main idea behind this method is to write tests to specify and validate what the code should do. Simply put, it is the practice of writing a test for a piece of functionality before writing the code.

The TDD methodology is a more balanced approach to software development that is mostly concerned with three main activities: coding, testing, and designing. Instead of chasing the best solution, the code and testing for that code are created one use case at a time. This process includes the following stages: Writing a test that fails due to the absence of a code (red). Write the code after which the test passes (green). Refactoring – examining the code structure and improving it without changing its external behavior. The expected result of refactoring is to achieve fully written code. In TDD, unit tests are written before software code is written. The code is then refactored to pass the tests again. This iterative process is repeated until all tests are green and there are no more failed tests. Once all tests are done and passed, the development team moves on to the next step in the process, such as adding features requested by the business team. The development process is divided into two phases—writing tests and writing code—TDD ensures that each piece of code is written only when it is needed, which avoids duplicate code and improves software quality.

Quality assurance is a crucial part of any project development process as it ensures the quality of the project and protects it against potential problems that may arise in the future. Quality assurance involves the following basic steps: Identifying the system requirements Creating the system design Implementing the project Testing the project Correcting any defects found in the system to ensure that all these steps are done during the development process. The system is of high quality and meets its requirements.

Let’s take a deeper look at the basic benefits of TDD: You just write the required code

Following principles, you should stop writing production code when all your tests have passed. If your project requires another feature, you may want to test the implementation of the feature to run. The code you write is the simplest code possible. Therefore, all code that ends up in production is needed to implement the features.

A More modular design

In TDD, you consider one microfeature at a time. And as you write the test first, the code automatically becomes easier to check. Code that is easy to inspect shows a clear interface. This leads to a modular design for your application.

Easier to maintain

Because the different parts of your application are separated from each other and have clear interfaces, the code becomes easier to maintain, and you can exchange microfeature implementations with better implementations without affecting other modules. You will also keep tests and rewrite entire applications. When all the tests are passed, you’re done.

Easier to refactor

Every feature is fully tested. You should not be afraid to make serious changes because if all the tests still pass, then everything is fine. Now, that’s extremely important because you, as a developer, improve your skills every day. If you open a project six months after performing on something else, chances are, you’ll have lots of ideas on ways to improve the code. But your memory of all the different parts and how they fit together is no longer fresh. Therefore, changes are often risky. With a complete test suite, you can easily modify the code without fear of breaking your application.

The tests document the code

Test code shows you how to use your code. As such, it documents your code. Test code is a sample code that shows what the code does and how the interface is used.

Code refactoring goes more smoothly

One of the biggest benefits of test-driven development is making code more manageable. Additionally, TDD helps to significantly reduce the total hours spent on testing and maintenance activities. Some studies show that application maintenance without TDD requires twice as much time compared to the software development lifecycle where TDD is used.

Refactoring is the next mandatory part of the TDD process, which is used for the optimization of existing code and follows one goal – to make it easier to introduce. If the code for a minor feature or improvement passes initial tests, it can be refactored to acceptable standards. This test-based approach also works with legacy code because it follows the same sequence: add one more test, run it, see if the new one fails, write the code, test, refactor, and repeat.


To conclude this, we can assume that implementing Test Driven Development significantly improves project results. Furthermore, we can say that developers who work with a TDD approach, have more structured thinking and generally give better estimates. This, of course, contributes to the benefits of implementing this approach in project development. There are a variety of best practices for strengthening the final code with TDD, such as CI, code reviews, refactoring, and others that are used by our developers at Hashtechy, If you’re someone looking for the best and structured practices of getting a project developed Hashtechy is your place!



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