Test-driven development – What is it, and how could it help you?

Delivering quality code in a small timeframe has become more critical than ever before. To increase their pace, organizations are moving towards integrating agile methodologies in their software development framework. However, this has resulted in organizations ignoring the importance of performing rigorous testing that leads to generating more bugs. This ends up taking a significant amount of the team’s time, which could have been utilized for working on the production or deployment of the product. Hence, to successfully tackle the issue of creating quality code at a rapid pace, test-driven development (TTD) has emerged.

Let’s understand test-driven development and explore its benefits and drawbacks, and how it can contribute to the organization’s overall success.

What is Test-Driven Development?

TDD is a software development practice that aims to create unit test cases before developing the actual code. It utilizes an iterative approach that combines refactoring, creating unit tests and programming. Deriving its roots from extreme programming and agile manifesto principles, TDD is a structuring practice that allows development and testing teams to procure optimized, resilient code in the long term.

Starting with designing and developing tests for small features of the product, the TDD framework instructs to create new code only if the automated test has failed. This helps the team to avoid duplication of scripts.

Steps for Implementing Test-Driven Development

TDD centres work around six simple steps that are repeated throughout the software development lifecycle. These steps ensure that the code is simple and efficient and fulfils the functional business requirements.

  • Writing the test

As the development in TDD is driven by a test, the first step involves creating a unit test. It should be effortless and only focus on testing a specific feature or component of a larger feature.

  • Running the test

After creating the test, the next step is to run it and confirm that it failed. This step enables to think about the requirements of the feature or section of a code.

  • Fixing the code

After the confirmation that the test has failed, the team should work on writing the code that will enable them to fix it. This step focuses on writing a test code that will satisfy the test conditions instead of writing the perfect solution.

  • Re-running the test

After creating the new testing script, the test should be re-run to check whether it passes the new test.

  • Refactoring

In this step, the team should refactor the code written in step 3 to integrate it with the existing codebase. The code should improve the readability of the test, distinguish it from logical parts, and rename or move variables and methods.

  • Repeat

TDD should be continued gradually to add features and functionality of the product. If all the test cases are small, the entire process, from writing a failing test to confirming a passing test and refactoring, can only take a few minutes. This helps to slowly progress towards a fully-realized feature, thereby, showing progress in the entire codebase.

Advantages of Test-Driven Development

  • Decreases the dependency on debugging

As TDD primarily focuses on creating the test case and only then creating code required to pass it, it further allows to dramatically decrease the requirement for debugging. Also, TDD helps to quickly identify and recognize a failing test as it advocates for a deeper understanding of logic and functional requirements during test case writing and coding.

  • Takes User Experience into account

Due to the nature of first thinking and then writing about the test, it should be fundamentally worked from backwards. It first considers the function that will be used, how it can be implemented, and how it needs to be written. Thus, TDD forces one to consider the functionality’s user experience elements and, therefore, the entire project.

  • Reduces overall development time

As per industry experts, when compared to the traditional, non-test-driven model, implementing TDD practices has helped organizations facilitate their total development time for a project. Even though the lines of code can stretch (because of the extra lines involved in tests), frequent testing prevents bugs and helps to catch existing ones much earlier in the process before they become problematic.

Conclusion

TDD shows the willingness of organizations to leave behind traditional approaches to software testing where tests are only run after the programming work is completed. It highlights the importance of testing when combined with development. This new approach gives a thorough understanding of how each part of the codebase works and assist them in catching errors before it’s too late in the development process. While it isn’t without its flaws, TDD’s benefits far outweigh its drawbacks if implemented correctly.