What is behavior-driven development?

1 The BDD cycle

BDD follows a cycle of discovery, formulation, and automation. In the discovery phase, the team collaborates with the stakeholders to elicit and explore the requirements and expectations of the system. They use techniques such as user stories, examples, and conversations to clarify the scope and value of each feature. In the formulation phase, the team translates the user stories and examples into executable specifications, using a structured language such as Gherkin. Gherkin is a domain-specific language that uses keywords such as Given, When, Then, and And to describe the preconditions, actions, and outcomes of each scenario. In the automation phase, the team implements the specifications as automated tests, using tools such as Cucumber, SpecFlow, or Behat. These tests serve as both documentation and verification of the system's behavior.

2 The benefits of BDD

BDD has several benefits for software development teams and projects. First, it promotes a shared understanding and alignment among the stakeholders, developers, and testers, by using a common and clear language to define and communicate the features and scenarios. Second, it encourages a user-centric and value-driven approach, by focusing on the outcomes and benefits of the system, rather than the technical details. Third, it supports a test-driven and agile process, by enabling the team to write and run tests before and during the development, and to deliver working software incrementally and iteratively. Fourth, it enhances the quality and maintainability of the code, by providing a living documentation and feedback mechanism that reflects the current state and behavior of the system.

3 The challenges of BDD

BDD is not a silver bullet and it also comes with some challenges and pitfalls, such as the risk of over-specification or duplication, difficulty of writing clear and concise specifications, and complexity of automation. To overcome these issues, the team should collaborate and communicate with stakeholders regularly and effectively, prioritize and refine user stories and examples based on value and feasibility, write specifications that are readable, understandable, and consistent, use abstraction and reusability to avoid duplication and complexity, choose and use the right tools and frameworks for automation, and review and update the specifications and tests as the system evolves.

4 The BDD tools and frameworks

There are numerous tools and frameworks available for BDD depending on the programming language, platform, and environment of the project. Popular choices include Cucumber, which is a cross-platform tool supporting Gherkin and integrating with various languages; SpecFlow, a .NET-specific tool that also supports Gherkin and works with Visual Studio, NUnit, and MSTest; Behat, a PHP-specific tool that integrates with Symfony, Laravel, and Drupal; Jasmine, a JavaScript-specific tool that works with Node.js, Angular, and React; and RSpec, a Ruby-specific tool that integrates with Rails, Sinatra, and Capybara. There are many more to explore and compare when selecting the right BDD tool or framework for your team and project.

5 The BDD resources and learning

If you want to learn more about BDD and how to apply it to your projects, there are plenty of resources and learning opportunities available. The Cucumber School offers courses and tutorials on BDD, Gherkin, and Cucumber, while the BDD Books series covers the theory and practice of BDD from experts and practitioners in the field. The BDD Podcast features interviews with BDD experts and enthusiasts from different backgrounds, while the BDD Community provides a platform for sharing experiences, questions, and tips.

BDD is a powerful and effective software development approach that can help you deliver better software faster and easier. By using a common language and format to define and verify the features and scenarios of your system, you can improve collaboration, communication, and quality. While it does require some skills, practices, and tools to implement it successfully, with some learning and experimentation you can reap the rewards of BDD. Enjoy the process of building software that matters!

6 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?