What is BDD? (Behavior-Driven Development)
By Hamid Akhtar, Community Contributor - July 17, 2023
As of 2023, Behavior-Driven Development (BDD) continues gaining traction in the software industry. This growth is fueled by the increasing recognition of BDD’s benefits in enhancing collaboration, improving requirement understanding, and facilitating early defect detection.
- As per Market Insights, the adoption of BDD is on an upward trajectory, with an unexpected Compound Annual Growth Rate (CAGR) projected from 2022 to 2029.
- The market size for BDD tools is also expected to reach multi-million USD by 2029, reflecting the growing demand for these tools in the industry.
- As Agile methodologies become more prevalent, BDD is a practical and effective approach for businesses to ensure software quality and meet customer needs.
What is BDD?
BDD is an approach in software development that emphasizes the behavior of an application for business needs. It was conceived to address issues arising from ill-defined requirement specifications and to align business and QA professionals.
BDD brings together key stakeholders in the Software Development Process, often called the “Three Amigos” – the Business, Development, and QA teams. Using tests written in plain English allows all stakeholders to understand and agree on the software’s expected behavior, ensuring that the “right product” is being developed.
The three principles of BDD are:
- Focus on the desired behavior or outcomes
- Collaboration between developers, testers, and business stakeholders
- Use of a common language for communication and understanding.
BDD is an evolution of the Test-Driven Development Methodology (TDD), but it shifts the focus from high test coverage to defining the application’s behavior.
- In BDD, behaviors are well-articulated, human-understandable statements that define a specific process in a predetermined format.
- These are stored in “feature files” integrated into the software development process.
- Tools like Cucumber and SpecFlow parse through the behaviors in the feature file and execute the “glue code” that maps behaviors to executable steps, known as “step definitions”.
For example, consider an online shopping platform. A behavior could be “When a user adds an item to the cart and proceeds to checkout, the item should be available for purchase.” This behavior is written in a feature file and then validated during development.
What is the BDD Process?
Think of BDD as a play. In a play, you have characters (the business team, the development team, and the QA team) and a script (the behaviors or requirements).
- The business team is like the playwright, writing the script based on what they want the audience (the users) to experience.
- The development team is like the actors, bringing the script to life on the stage (the software).
- The QA team is like the director, ensuring the actors perform their parts correctly and the play goes as planned.
In BDD, the “script” is written in a language called Gherkin, which uses simple words like “Given”, “When”, and “Then” to describe the behavior of the software. For example, “Given a user is logged in, When they click on the ‘logout’ button, they should be logged out and redirected to the login page.” This script is then turned into automated tests that check if the software behaves as expected.
The beauty of BDD is that everyone involved in the play, from the playwright to the director, understands the script and agrees on the final performance. This way, everyone is on the same page, and the chances of the play being a hit are much higher!
Advantages of BDD
Imagine you’re planning a surprise birthday party for your friend. You have a team: you, who knows your friend best (like the business team), your friend who loves to cook (like the development team), and your other friend who’s great at organizing events (like the QA team). Now, how can BDD help you throw the best party?
- Better collaboration/communication: BDD is like a party planning meeting where everyone sits together and discusses the plan. You talk about what your friend likes, the cook suggests the menu, and the organizer plans the decorations. Everyone understands the plan and works together to make the party a success.
- Enhanced requirement understanding: It’s like knowing exactly what your friend would love at the party. You know she loves chocolate cake, so the cook knows to bake a chocolate cake. You know she loves balloons, so the organizer knows to get lots of balloons. There’s clarity and understanding about what needs to be done.
- Early defect detection: This is like doing a trial run of the party. You taste the cake beforehand to make sure it’s delicious. You check the decorations to make sure they look good. If anything’s not right, you can fix it before the party.
- Increased test coverage: This is like ensuring every part of the party is perfect. You don’t just taste the cake, you also taste the other dishes. You don’t just check the decorations, you also check the music, the lighting, and the seating arrangement. You make sure every aspect of the party is just right.
So, just like planning a perfect party, BDD helps develop a perfect software product. It ensures everyone works together, understands what needs to be done, catches mistakes early, and checks every part of the product to ensure it’s right.
Read More: How to achieve Advanced BDD Test Automation?
Limitations of BDD
Let’s go back to the birthday party example. While planning a party using the BDD approach has advantages, it can also face some challenges.
- Cultural and organizational barriers: Imagine if your team members need to be used to planning parties together. The cook may be used to deciding the menu alone, and the organizer is used to planning the decorations alone. They might find it difficult to start working together and discussing their plans suddenly. This is similar to how some teams might find it challenging to adopt BDD if they are not used to collaborating closely and discussing requirements.
- Overemphasis on tooling and syntax: This is like focusing too much on the party planning app you’re using to organize the party, rather than the party itself. You spend so much time learning how to use the app and getting the syntax right that you must remember to plan the party. Similarly, in BDD, teams can sometimes focus too much on the tools and the Gherkin syntax and need to remember the actual purpose of BDD, which is to improve collaboration and requirement understanding.
- Maintaining up-to-date and relevant specifications is like updating the party plan. Maybe the cook decides to change the menu, or the organizer decides to change the decorations. Everyone needs to be informed about these changes, and the party plan needs to be updated. Similarly, keeping the specifications (or “scripts”) up-to-date in BDD can be challenging. If the requirements change, the scripts must be updated, and everyone needs to be informed about the changes.
So, while BDD can help in planning a great party (or developing a great software product), it’s important to be aware of these challenges and find ways to overcome them.
BDD Tools and Frameworks
Just like you need the right tools to throw a great party (like a good oven for the cook and a good planning app for the organizer), you need the right tools to implement BDD effectively..
- Cucumber is a tool that supports BDD. It allows you to write your tests in a language called Gherkin, which is easy to understand for both technical and non-technical team members. It’s like having a simple recipe that everyone can follow to bake the perfect cake for the party.
- SpecFlow is another tool for BDD. It’s similar to Cucumber but specifically designed for .NET projects. It’s like having a specialized oven perfect for baking a specific type of cake.
When choosing a BDD tool, you need to consider factors like the programming language of your project, the complexity of your tests, and the tool’s features. Remember, the right tool can make implementing BDD much smoother and more efficient, just like the right oven can make baking a cake easier and more successful.
BDD Best Practices
When working with Behavior-Driven Development (BDD), following some best practices is important to ensure you’re getting the most out of this approach.
Here are some key points to keep in mind:
- Write Scenarios Early: You should start writing your test scenarios as early as possible. This helps you define the software behavior and understand potential problems better. It’s like planning your trip before you start your journey. It saves time and reduces uncertainty later during development.
- Focus on One Behavior per Scenario: Each scenario should cover exactly one behavior. This makes it easier to understand, automate, and maintain. It’s like cooking a dish, you focus on one recipe at a time to ensure it turns perfect.
- Use Background Wisely: If there are steps that are repeated in every scenario, put them in the Background.
- Reuse Step Definitions: Try reusing the step definitions you frequently use in various scenarios.
- Use Data Tables and Scenario Outlines: When you have a large data set, use Data Tables and Scenario Outlines.
- Use Tags: Tags can help you organize and run specific groups of scenarios. It’s like labeling your food containers in the fridge so you can easily find what you’re looking for.
- Write in a Declarative Way: Scenarios should be written how the user would describe them. Avoid scenarios that only describe clicking links and entering data in form fields.
- Good Grammar: Write like your high school English teacher will be grading your Gherkin. Poor grammar, misspellings, and inconsistent phrasing can ruin the benefits of behavior specification.
Remember, BDD aims to improve collaboration and understanding among team members. So, keep your scenarios simple, clear, and focused on behavior.
Importance of BDD in Software Development
BDD is a powerful tool in software development, acting as a bridge between technical and non-technical stakeholders. It’s like a universal translator in a sci-fi movie, enabling everyone to understand each other clearly. BDD ensures that the development projects remain focused on the business’s needs while meeting the user’s requirements.
By encouraging collaboration across different roles, BDD helps to build a shared understanding of the problem that needs to be solved. It’s like a team huddle in a football game where everyone gets on the same page about the next play. This approach allows for rapid iterations, increasing feedback, and enhancing the flow of value.
Most importantly, BDD improves code quality, which helps reduce variable expenses like maintenance costs and minimizes project risk. It’s like building a house with high-quality materials and a solid foundation, ensuring it stands strong for years.
In essence, BDD practices are a powerful tool to help teams develop better software by demanding prudent specificity of product behaviors using examples in plain language.
What is BDD Testing?
BDD Testing is a unique approach that defines the application’s behavior to make it optimal for business needs. It’s like a chef carefully crafting a recipe to ensure the dish is perfect for the customers.
- In BDD Testing, behaviors are well-articulated, human-understandable statements that define a specific process in a predetermined format.
- These are stored in a “feature files” set that is then integrated into the software development process.
- It creates Feature files in a domain-specific language, and then the Development, Business Analysis, and Quality Assurance teams concur on the Feature and Scenarios.
The importance of BDD Testing lies in its ability to ensure that the software aligns with what the customers have in mind. It’s like ensuring the dish tastes good and meets customer expectations.
How do BDD and Test Management Interrelate?
Behavior-Driven Development (BDD) and Test Management are like two sides of the same coin, each complementing the other to ensure the successful delivery of a software product. In essence, BDD and Test Management interrelate by ensuring that the software meets the business requirements and passes all the necessary tests to ensure its quality and reliability.
- BDD is like a blueprint, clearly showing what the software should do. It’s like a detailed recipe that guides the chef (the development team) in preparing the dish (the software). The recipe is written in a language (Gherkin) that everyone in the kitchen (the project team) can understand.
- On the other hand, Test Management is like the kitchen manager, ensuring that the recipe is followed correctly and the dish is prepared as expected. It involves planning, executing, and tracking tests, and managing and mitigating risks.
When BDD and Test Management work together, they create a powerful combination that can significantly improve the software development process. BDD ensures that everyone understands what needs to be done, while Test Management ensures it’s done correctly.
With BrowserStack Test Management, you can create, manage, and track your manual and automated test cases end-to-end using simple, integrated workflows and powerful dashboards.
In conclusion, Behavior-Driven Development (BDD) is not just a methodology; it’s a mindset that can revolutionize how we approach software development. It’s about breaking down the walls between business and technology, fostering collaboration, and ensuring we’re building the right product for the right reasons.
From understanding the adoption statistics of BDD to diving deep into its process, benefits, challenges, tools, and best practices, we’ve explored the many facets of this approach.
By incorporating Agile processes and advanced BDD Test Automation, meet the demands of your discerning user base and expedite product delivery. However, the crux lies in delivering a product that precisely aligns with customer expectations.