Skip to main content
Version: 2.0.0

What is Behavior Driven Development (BDD)?

Behavior-driven development (BDD) is an Agile software development methodology that encourages collaboration between developers, testers, and business stakeholders. BDD is based on the idea that the best way to ensure that software meets the needs of its users is to write tests that describe the desired behavior of the software in plain language.

Benefits of BDD

  1. Improved communication: BDD encourages communication between developers, testers, and business stakeholders. This helps to ensure that everyone is on the same page and that the software meets the needs of its users.
  2. Increased collaboration: BDD encourages collaboration between developers, testers, and business stakeholders. This helps to ensure that the software is developed in a way that is efficient and effective.
  3. Improved testability: BDD tests are written in plain language, which makes them easier to understand and maintain. This helps to improve the testability of the software.
  4. Increased confidence: BDD tests provide a high degree of confidence that the software meets the needs of its users. This helps to reduce the risk of defects and to improve the quality of the software.

Overall, BDD is a software development process that can help to improve communication, collaboration, and testing. This can lead to the development of higher-quality software that meets the needs of the business.

Key Principles of BDD:

BDD is guided by several key principles that shape its approach to software development:

Collaboration: BDD encourages collaboration between different stakeholders, including developers, testers, and business representatives. By fostering open communication, BDD helps align everyone's understanding of the desired software behavior.

User Stories and Scenarios: BDD uses user stories and scenarios to define the expected behavior of the software from the end user's perspective. These scenarios, written in plain language, serve as the basis for developing and testing the application.

Gherkin Language: BDD employs the Gherkin language, a simple, human-readable syntax that allows stakeholders to describe the behavior of a system. Gherkin uses keywords like Given, When, and Then to articulate the preconditions, actions, and expected outcomes, making it accessible to non-technical team members.

Automated Testing: One of the core practices in BDD is the creation of automated tests based on the defined scenarios. These tests validate that the software behaves as specified in the Gherkin scenarios, providing rapid feedback to developers and ensuring continuous integration and delivery.

BDD Testing Tools

Here are some of the popular BDD automation tools:

  1. Cucumber: Cucumber is a free and open-source BDD tool that uses the Gherkin syntax for writing test cases in plain English. It can be programmed in several languages, including Java, Ruby, and JavaScript.

  2. Behave: Behave is a behavior-driven testing tool written in Python that supports the Gherkin syntax and can be used in tandem with other testing frameworks like Pytest and Unittest.

  3. JBehave: JBehave is a Gherkin-based, Java-based BDD tool that supports many testing frameworks, including JUnit and TestNG.

  4. SpecFlow: SpecFlow is a BDD tool that interfaces with Microsoft Studio and other .NET tools and employs the Gherkin syntax for writing specifications. It can be programmed in C# and Visual Basic, among other languages.

  5. Gauge: Gauge is an open-source BDD tool that employs a markdown-based syntax to describe tests. It can be programmed in Java, Ruby, and Python, among others.

  6. Reqnroll: Reqnroll is an open-source Cucumber-style BDD test automation framework for .NET.

These tools can help to streamline the testing process and improve communication between developers, testers, and stakeholders. This can help to ensure that the software meets the needs of the business and is of high quality.

Points to remember while using BDD

  1. BDD is not a silver bullet: BDD is not a magic solution that will solve all of your software development problems. However, it can be a valuable tool for improving communication, collaboration, and testability.
  2. BDD requires buy-in from everyone involved: BDD is most effective when everyone involved in the software development process is on board. This includes developers, testers, and business stakeholders.
  3. BDD takes time to learn and implement: BDD is a new approach to software development, and it takes time to learn and implement. However, the benefits of BDD can be significant, so it is worth the investment.
  4. BDD is not a replacement for other testing methods: BDD is not a replacement for other testing methods, such as unit testing and integration testing. Instead, it should be used in conjunction with these methods to improve the overall quality of the software.
  5. BDD is not a replacement for other testing methods: BDD is not a replacement for other testing methods, such as unit testing and integration testing. Instead, it should be used in conjunction with these methods to improve the overall quality of the software.

TDD vs BDD

While TDD primarily centers around unit testing and code design, BDD emphasizes collaboration and end-user behavior.

Test Driven Developement revolves around the practice of writing unit tests before implementing code, primarily emphasizing the correctness of individual code units. Developers write tests using the same programming language as the application code, focusing on small, isolated portions of code through a cycle of writing tests, implementing code, and refactoring. TDD primarily targets developers and is centered on automated unit testing using frameworks like JUnit or pytest.

In contrast, Behavior Driven Development prioritizes collaboration and the overall behavior of the system from the end user's perspective. BDD scenarios are written in natural language using tools like Cucumber or SpecFlow, making them accessible to both technical and non-technical stakeholders. BDD encourages collaboration among developers, testers, and business stakeholders to define and validate system behavior. It spans different testing levels, including acceptance, integration, and system testing, and aims to ensure that the software meets user expectations.

While TDD focuses on code-level testing and is developer-centric, BDD broadens its scope to involve multiple stakeholders, emphasizing the system's behavior in natural language. The choice between TDD and BDD often depends on project requirements, team dynamics, and the desired level of collaboration and communication among team members. Both methodologies contribute to improving software quality, but they approach testing and development from different perspectives, addressing different aspects of the software development lifecycle.