What is the Difference Between TDD and BDD

The main difference between TDD and BDD is that TDD focuses on single units or features of an application, but BDD focuses on the entire application as a whole.

Generally, enterprise-level software development is a complex task. Teams follow various processes throughout the software life cycle – from requirement gathering to delivering the product to the customer and handling maintenance activities.  TDD and BDD are software processes. In brief, BDD is based on TDD.

Key Areas Covered

1. What is TDD
     – Definition, Functionality
2. What is BDD
     – Definition, Functionality
3. Difference Between TDD and BDD
     – Comparison of Key Differences

Key Terms

Behavior Driven Development, Test Driven Development, TDD Life Cycle, Software Development

Difference Between TDD and BDD - Comparison Summary

What is TDD

TDD stands for Test Driven Development. It is a software development process that consists of small development cycles. In this process, after collecting the requirements, those requirements are turned into specific test cases. Then the programmer can implement the software and improve it to pass only the tests.

Moreover, TDD is the reverse of traditional development. In traditional development, implementing the code comes first, and then the testing of it. In contrast, in TDD, testing comes first and then implementing.

Difference Between TDD and BDD

TDD Life Cycle

Add a test – It involves writing a test for each new feature. To write a test, the developer should have a good understanding of the requirements. He can study user cases and stories to identify the requirements. Thus, it makes the developer focus more on the requirements.

Run all tests and see if the new test fails – It validates that the test harness is working correctly.

Write the code – It involves writing code to pass the test. The written code may not be excellent at this stage. However, it will be improved later. The main objective of writing the code is to pass the test. It only covers the functionality necessary for testing.

Run tests – If the test cases are passed, then the new code satisfies the test requirements. It ensures that the new code does not degrade the existing features. If the test cases are not passed, the programmer has to adjust them until they pass.

Refactor code –This step involves multiple tasks. Moving the code to a place where it logically belongs to, eliminating the duplication, clearly representing objects, classes, modules, variables and methods, improving the readability and maintainability are some activities. The main objective is to get a clean code. Running the test cases again and again during the refactoring phase ensures existing functionalities work properly.

The above steps are repeatd again for another new test case. If the tests fail continuously, the programmer has to debug the code.

What is BDD

BDD stands for Behavior Driven Development. It allows a team of members to collaborate and to understand how the application should behave. It uses the techniques and principles of TDD with domain-driven design and object-oriented analysis and design. All these allow the development and management teams to share tools and processes during software development. BDD involves using specialized software tools to develop the project. Furthermore, the tools developed for BDD projects also support TDD.

BDD highly depends on the simple domain specific language (DSL), using natural languages constructs similar to the English language to describe the behaviours and outcomes. Test scripts are a popular application of DSL. Overall, BDD is a useful practice to solve complex business problems.

Difference Between TDD and BDD

Definition

TDD is a software development process in which the first step is to turn the requirements into specific test cases, and then improving the software to pass the new tests. In contrast, BDD is an agile software development process. It promotes developers, QA, and non-technical or business participants to work collaboratively in a software project. Hence, this explains the fundamental difference between TDD and BDD.

Stands for

TDD stands for Test Driven Development whereas BDD stands for Behavior Driven Development.

Functionality

In TDD, the tests are written to cover each functionality or unit while BDD focuses on the application as a whole. Thus, this is the main difference between TDD and BDD.

 Scenarios

Moreover, another difference between TDD and BDD is that the TDD involves designing high-level scenarios, whereas BDD involves designing low-level scenarios. 

Conclusion

In brief, TDD and BDD are two software development approaches. Furthermore, a programmer can select one of them depending on the scenario. The main difference between TDD and BDD is that the TDD focuses on single units or features of an application, while BDD focuses on the entire application as a whole.

References:

1.“Test-Driven Development.” Wikipedia, Wikimedia Foundation, 21 May 2019, Available here.
2.“Behavior-Driven Development.” Wikipedia, Wikimedia Foundation, 15 May 2019, Available here.

Image Courtesy:

1.”3335977″ via (CC0) Pixabay

About the Author: Lithmee

Lithmee holds a Bachelor of Science degree in Computer Systems Engineering and is reading for her Master’s degree in Computer Science. She is passionate about sharing her knowldge in the areas of programming, data science, and computer systems.

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