Behavior-driven development

Behavior-driven Development

Behavior-driven development (BDD) is a software development methodology that emphasizes collaboration between developers, quality assurance, and non-technical or business participants in a software project. It encourages teams to use conversation and concrete examples to formalize a shared understanding of how the application should behave.

Overview

BDD extends test-driven development (TDD) by writing test cases in a natural language that non-programmers can read. This approach helps ensure that all stakeholders have a clear understanding of the system's behavior.

Key Concepts

Ubiquitous Language

BDD promotes the use of a ubiquitous language, a common language shared by all team members, to describe the behavior of the system. This language is used in writing user stories and acceptance criteria.

User Stories

User stories in BDD are often written in the format:

• As a [role]
• I want [feature]
• So that [benefit]

This format helps clarify who the feature is for, what the feature is, and why it is needed.

Scenarios

Scenarios are written to describe specific examples of how the system should behave. They are often written in the "Given-When-Then" format:

• Given some initial context
• When an event occurs
• Then ensure some outcomes

This format helps in structuring the behavior in a clear and understandable way.

Tools

Several tools support BDD by allowing tests to be written in natural language. Some popular BDD tools include:

• Cucumber
• JBehave
• SpecFlow

These tools parse the natural language statements and map them to code that executes the tests.

Benefits

• Improved Communication: BDD fosters better communication among team members by using a common language and involving all stakeholders in the process.
• Shared Understanding: By focusing on the behavior of the system, BDD helps ensure that everyone has a shared understanding of what the system should do.
• Living Documentation: The scenarios written in BDD serve as living documentation that evolves with the system.

Challenges

• Initial Learning Curve: Teams new to BDD may face a learning curve as they adapt to writing scenarios and using BDD tools.
• Maintaining Scenarios: As the system evolves, keeping scenarios up-to-date can be challenging.

See Also

• Agile software development
• Test-driven development
• Acceptance test-driven development

References

• North, Dan. "Introducing BDD." Dan North & Associates, 2006.
• Wynne, Matt, and Aslak Hellesøy. "The Cucumber Book: Behaviour-Driven Development for Testers and Developers." Pragmatic Bookshelf, 2012.