Behavior-Driven Development (BDD) Methodology

A Behavior-Driven Development (BDD) Methodology is an agile software development methodology that emphasizes collaboration between developers, testers, and business stakeholders to ensure customer-centric outcomes through behavior specification in natural language.

• AKA: Specification by Example.
• Context:
  • It can typically foster Collaborative Development through three amigos collaboration (business, development, and QA teams).
  • It can typically describe Software Behavior using natural language specifications with Given-When-Then format.
  • It can typically create Executable Specifications that serve as both automated tests and living documentation.
  • It can typically bridge Communication Gaps between technical team members and non-technical stakeholders.
  • It can typically support Test-First Development by defining behavior tests before implementation code.
  • ...
  • It can often use Domain-Specific Languages like Gherkin language for behavior description.
  • It can often implement Outside-In Development focusing on user-facing behavior before internal implementation.
  • It can often integrate with Continuous Integration Pipelines for automated behavior verification.
  • It can often reduce Requirements Misunderstandings through concrete examples and shared understanding.
  • ...
  • It can range from being a Simple BDD Implementation to being a Complex BDD Implementation, depending on its BDD automation level.
  • It can range from being a Technical BDD Practice to being a Business-Focused BDD Practice, depending on its BDD stakeholder emphasis.
  • ...
  • It can utilize BDD Frameworks such as Cucumber, SpecFlow, JBehave, or Behave.
  • It can employ Step Definitions to link scenario steps to executable code.
  • It can maintain Feature Files containing business-readable scenarios.
  • It can support Living Documentation that evolves with system behavior.
  • It can enable Rapid Iterations through quick feedback loops.
  • ...
• Examples:
  • BDD Framework Implementations, such as:
    • Cucumber BDD Frameworks, such as:
      • Cucumber for Java supporting Java-based BDD testing.
      • Cucumber.js enabling JavaScript BDD implementation.
      • Cucumber-Ruby for Ruby BDD development.
    • .NET BDD Frameworks, such as:
      • SpecFlow providing .NET BDD testing capability.
      • NBehave for .NET behavior specification.
    • Python BDD Frameworks, such as:
      • Behave enabling Python BDD testing.
      • Pytest-BDD combining pytest framework with BDD approach.
  • BDD Practice Levels, such as:
    • Unit-Level BDD focusing on component behavior specification.
    • Integration-Level BDD describing system interaction behavior.
    • Acceptance-Level BDD defining end-to-end user behavior.
  • Industry-Specific BDD Implementations, such as:
    • Financial Services BDD for regulatory compliance testing.
    • E-commerce BDD for customer journey specification.
    • Healthcare BDD for clinical workflow validation.
  • ...
• Counter-Examples:
  • Test-Driven Development (TDD), which focuses on technical tests rather than business behavior specification.
  • Acceptance Test-Driven Development (ATDD), which emphasizes acceptance criteria but may lack natural language specification.
  • Traditional Waterfall Testing, which performs testing phases after development completion.
  • Code-First Development, which implements functionality before defining expected behavior.
• See: Agile Software Development, Test-Driven Development, Domain-Driven Design, Gherkin Language, Cucumber Framework, User Story, Acceptance Criteria, Living Documentation, Three Amigos, Specification by Example.

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References

2023

• chat
  • Behavior-Driven Development (BDD) is a software development methodology that emphasizes collaboration, communication, and shared understanding between developers, testers, and business stakeholders. BDD aims to ensure that software is developed according to well-defined requirements and user expectations. It extends from Test-Driven Development (TDD) and borrows concepts from Domain-Driven Design (DDD).

     BDD focuses on specifying the desired behavior of a software system in a clear, understandable language. This is achieved by writing scenarios or test cases in plain language, which can be understood by both technical and non-technical stakeholders. The plain language format enables everyone on the team to participate in the development process and to have a shared understanding of the system's behavior.

  • Key principles of BDD include:
    • Collaboration: BDD promotes active involvement from all team members, including developers, testers, and business stakeholders, ensuring that everyone contributes to the development process and shares a common understanding of the system's goals.
    • Ubiquitous language: BDD encourages the use of a consistent, shared language to describe the system's behavior. This language is used in writing test scenarios and discussing requirements, making it easier for everyone to understand and contribute to the development process.
    • Specification by example: BDD focuses on defining concrete examples to illustrate the desired behavior of the system, rather than abstract requirements. These examples serve as the basis for test scenarios and help to clarify the expectations of the system for all team members.
    • Living documentation: In BDD, the test scenarios serve as up-to-date documentation of the system's behavior. As the scenarios are written in plain language, they are easy to understand and maintain, ensuring that the documentation remains relevant and useful throughout the development process.
  • BDD is often implemented using tools like Cucumber, which allows the execution of automated tests written in a domain-specific language like Gherkin. These tools facilitate the writing and execution of plain-language tests, bridging the gap between technical and non-technical stakeholders and fostering effective collaboration.

2023

• (Wikipedia, 2023) ⇒ https://en.wikipedia.org/wiki/Behavior-driven_development Retrieved:2023-4-4.
  • In software engineering, behavior-driven development (BDD) is an agile software development process that encourages collaboration among developers, quality assurance experts, and customer representatives in a software project. It encourages teams to use conversation and concrete examples to formalize a shared understanding of how the application should behave. It emerged from test-driven development (TDD). Behavior-driven development combines the general techniques and principles of TDD with ideas from domain-driven design and object-oriented analysis and design to provide software development and management teams with shared tools and a shared process to collaborate on software development. Although BDD is principally an idea about how software development should be managed by both business interests and technical insight, the practice of BDD does assume the use of specialized software tools to support the development process.

    Although these tools are often developed specifically for use in BDD projects, they can be seen as specialized forms of the tooling that supports test-driven development. The tools serve to add automation to the ubiquitous language that is a central theme of BDD.

     BDD is largely facilitated through the use of a simple domain-specific language (DSL) using natural-language constructs (e.g., English-like sentences) that can express the behaviour and the expected outcomes. Test scripts have long been a popular application of DSLs with varying degrees of sophistication. BDD is considered an effective technical practice especially when the "problem space" of the business problem to solve is complex.

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