What is BDD / Behaviour Driven Development?

Introduction

In the world of software development, methodologies like Agile and Scrum have revolutionized the way projects are managed. One such methodology that has gained popularity in recent years is Behavior Driven Development (BDD). BDD focuses on collaboration, communication, and delivering value through a shared understanding of desired behaviors. In this blog post, we will explore what BDD is, its advantages, and provide an example to help you grasp this concept better.

What is BDD?

Behavior Driven Development (BDD) is a software development approach that aims to bridge the gap between business stakeholders, developers, and testers by promoting effective communication and collaboration. It encourages teams to focus on the behavior of software rather than the technical implementation details.

BDD takes its inspiration from Test Driven Development (TDD) and Domain Driven Design (DDD) and provides a common language for all stakeholders involved. It uses a structured format called Gherkin, which allows stakeholders to define and express the expected behavior of the system in a natural language format.

What are the advantages of BDD?

Enhanced Collaboration

BDD fosters collaboration among different roles involved in software development, including business analysts, developers, and testers. By using a common language and understanding of behaviors, BDD enables effective communication and alignment of goals. This collaborative approach reduces misunderstandings and ensures that all team members have a shared vision of the desired system behavior. As a result, stakeholders can work together seamlessly, leveraging their collective expertise to deliver high-quality software.

Clear and Understandable Documentation

BDD provides clear and understandable documentation that serves as a valuable reference throughout the software development lifecycle. Gherkin scenarios, written in a natural language format, offer a concise representation of the system's behavior. These scenarios serve as living documentation that can be reviewed and updated as the system evolves. The structured format not only captures the expected outcomes but also includes contextual information, such as user roles and business goals. This level of detail ensures that the documentation is comprehensive, making it easier to onboard new team members and maintain a shared understanding of the system's behavior.

Improved Test Coverage

BDD encourages the creation of automated tests that validate the expected behavior of the system. These tests, often written using frameworks like Cucumber or SpecFlow, ensure that the software functions correctly from the end user's perspective. By focusing on behavior, BDD helps identify gaps in test coverage and ensures that critical functionalities are thoroughly tested. The collaborative nature of BDD also enables stakeholders to contribute to test scenarios, providing a broader perspective and reducing the risk of overlooking important scenarios. The result is improved test coverage and increased confidence in the reliability of the software.

Early Detection of Issues and Improved Quality

BDD promotes a proactive approach to software development by encouraging early collaboration and continuous feedback. By involving stakeholders in the behavior specification process, potential issues and misunderstandings can be identified and addressed early on, reducing the likelihood of costly rework. The use of executable scenarios in BDD allows for quick validation of system behavior, enabling early detection of defects and ensuring that the software meets the desired functionality. With BDD, teams can focus on building high-quality software that aligns with user expectations, leading to increased customer satisfaction and a reduced risk of post-release issues.

BDD Example

Let's take a simple example to understand how BDD works. Imagine you're developing an e-commerce website, and one of the requirements is to allow users to add items to their shopping cart.

Here's how a BDD scenario might look in Gherkin syntax:

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"gherkin

Copy code

Feature: Shopping Cart

  As a customer

  I want to add items to my shopping cart

  So that I can review and purchase them later"

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Scenario: Add items to the shopping cart

  Given I am on the product page

  When I click on "Add to Cart" for a product

  Then the product should be added to my shopping cart

  And the shopping cart should display the correct number of items

In this example, the scenario describes the behavior of adding items to the shopping cart from a customer's perspective. It captures the expected outcome and provides a clear understanding of the desired functionality. This scenario can be used as a reference by developers to implement the feature and by testers to validate its behavior.

Conclusion

Behavior Driven Development (BDD) is a valuable approach for software development that emphasizes collaboration, communication, and delivering value. By focusing on the behavior of the system and using a common language, BDD bridges the gap between business stakeholders, developers, and testers. It improves collaboration, provides clear and understandable documentation, and enhances test coverage. By adopting BDD, teams can build software that meets the desired behaviors and delivers value to the end users.

Remember, as Albert Einstein once said, "If you can't explain it simply, you don't understand it well enough."