TDD vs BDD – What’s the Difference Between TDD and BDD?


As a software developer, you might have come across the terms in your organization or elsewhere. But what do they mean, and how are they different? In this article, we will delve into TDD vs BDD, exploring the key differences between these two popular software development methodologies.


What is TDD [Test Driven Development]?


Test-driven development (TDD) is a software development technique in which test cases are written before the code to make the test pass is written. This approach involves writing a small amount of code to make the test pass and then adding functionality to the code incrementally. Test Driven Development focuses on the development process and ensures that code meets the desired functionality at every stage of development. TDD can be done using any programming language, and there are several frameworks available to support TDD, including JUnit and NUnit.


What is Behavior Driven Development?


Behavior-driven development (BDD) is another software development methodology that emerged out of TDD. BDD focuses on the behavior of an application, rather than on writing the code to make the test pass. The BDD approach involves writing test cases that are written from the user’s perspective and are more accessible to customers, BA, and other members. BDD test cases are written in simple English, using tools like Gherkin and Cucumber . BDD also involves collaboration between developers, QA, and BA’S to ensure that all members are aligned with the product requirements and that the application behaves as expected.


What are the key differences between TDD vs BDD [Test-Driven Development & Behavior-Driven Development]  Approaches


Although they are different development techniques, they are related in that they both approach writing test cases in a similar way. TDD focuses on the functionality of the code, while behavioral driven development focuses on the application’s behavior. Both involve the entire development team, including developers, testers, and others, to ensure that the product requirements are met and that the application behaves as expected. Both methodologies are also commonly used in agile development environments because they provide rapid feedback and ensure that the application is of high quality.


What are the benefits of TDD and BDD in Software Development?


Both techniques have several benefits for SDLC. TDD benefits include: improving the quality of the code, reducing the number of defects in the code, and improving collaboration among team members. BDD benefits include improved communication between developers, QAS, and business analysts, facilitating collaboration and teamwork, and ensuring that development aligns with end user’s or the customer’s objectives. Both other techniques help to reduce the cost of software development by detecting defects early in the development process, which saves time and resources.


How are Behavioral Driven Development test cases written?


BDD Test Cases are designed using a framework called Gherkin. It is a language or specification that is designed to be easily understood by all stakeholders in a software project, including business analysts, developers, testers, product owners etc, documents application behavior, and helps to collaborate. Gherkin uses plain English to define acceptance criteria for each feature, which helps to ensure that the feature meets the requirements of the customer. The approach also involves collaboration between BA’s , and testers to define the acceptance criteria and write the test cases. The test cases are also written using tools like Cucumber, which is an automated testing tool that generates executable test scripts automatically based on the Gherkin language.


What is test automation in TDD and BDD?


In TDD, automation is used to run the test cases repeatedly, ensuring that the code meets the requirements at every stage of development. Automated Test Scripts in BDD is focused on automating the acceptance criteria defined in Gherkin. Automated Tests help to detect defects early, which saves time and resources in the development life cycle. Tools used include Selenium, which is a tool used to test web applications, and Cucumber, which is a BDD framework used to generate test scripts.


In summary, we have explored what is different between BDD vs TDD. While TDD aims on writing code that meets the desired functionality, whereas BDD aims at the behavior of the application. However, both are similar in that they both involve the development team and are commonly used in agile development environments. When choosing between the two, it is important to consider the project requirements and the development team’s strengths and weaknesses.


Both techniques have benefits and help to reduce the cost of development by detecting defects early in the development process. Adopting TDD or BDD or a combination of both can help your organization to improve collaboration among stakeholders and deliver high-quality software products.


Leave a Reply