Behavior-Driven Development (BDD) is a process that gives examples of how software should behave in various scenarios. This behavior is written in a format that is easily understood, tested, and integrated.
Aspect
Explanation
Definition
Behavior-Driven Development (BDD) is a software development approach that focuses on the behavior of a software application from the end user’s perspective. It emphasizes collaboration among developers, testers, and non-technical stakeholders to define and prioritize user-centric behaviors or features. BDD uses natural language specifications and automated tests to ensure that the software meets these behavioral requirements. BDD is an evolution of Test-Driven Development (TDD) with a stronger emphasis on the business value delivered by software.
Key Concepts
– Behavior Specifications: Defining the expected behavior of the software in plain language using scenarios and examples. – Collaboration: Encouraging collaboration between developers, testers, and business stakeholders. – Automated Testing: Writing automated tests that validate whether the software behaves as specified. – User-Centric Focus: Prioritizing behaviors that provide value to end users. – Continuous Feedback: Providing constant feedback to improve the software’s behavior.
Characteristics
– Scenario-Driven: BDD scenarios describe how the software should behave under specific conditions. – User Stories: User stories or features serve as the basis for behavior specifications. – Automation: BDD encourages the automation of tests to ensure continuous validation of behavior. – Cross-Functional Teams: Collaboration involves multiple roles, including developers, testers, and product owners. – Language-Driven: BDD scenarios are often written in plain language for easy understanding.
Implications
– Improved Collaboration: Enhances communication between development and business teams. – Clear Requirements: Ensures that software behavior is well-defined and understood by all stakeholders. – Early Detection of Issues: Automated tests catch behavior-related issues early in development. – User Satisfaction: Focus on user-centric behaviors results in more valuable software. – Reduced Rework: Clear specifications reduce the need for rework due to misunderstood requirements.
Advantages
– Enhanced Communication: Improved communication between technical and non-technical team members. – Higher Quality: Automated tests provide continuous feedback, reducing defects. – User-Centric Development: Prioritizes features that matter most to end users. – Clarity: Clear behavior specifications reduce ambiguity in requirements. – Efficiency: Avoids building unnecessary features, saving time and resources.
Drawbacks
– Learning Curve: BDD may require a learning curve for teams new to the methodology. – Time-Intensive: Writing detailed behavior specifications and automated tests can be time-consuming. – Tool Dependencies: Reliance on specific BDD tools or frameworks. – Misalignment: Misalignment between business goals and behavior specifications can occur. – Maintenance Overhead: Maintaining behavior specifications and tests as software evolves.
Applications
– Software Development: BDD is widely used in software development, particularly in Agile and DevOps environments. – Web Development: Testing and ensuring the behavior of web applications. – Mobile App Development: Ensuring mobile apps meet user expectations. – API Development: Validating API behavior and functionality. – Embedded Systems: Verifying the behavior of embedded software in devices.
Use Cases
– E-commerce Platform: Ensuring smooth checkout and payment behavior. – Social Media App: Validating user interaction and content posting behavior. – Financial Software: Verifying transaction processing and security behavior. – Healthcare Application: Testing patient record management and data privacy behavior. – Gaming Software: Ensuring gameplay and user interface behavior aligns with expectations.
Future Trends
– AI-Driven Testing: Integration of AI and machine learning for more advanced test automation. – Behavior Visualization Tools: Tools that provide interactive visualization of behavior scenarios. – Cross-Platform Support: Expanding BDD practices to cover cross-platform and multi-device behavior. – Integrated DevOps: Tighter integration of BDD into DevOps pipelines for continuous behavior validation. – Behavior-Driven Business Analysis: Expanding BDD principles to business analysis and requirements gathering.
During the software development process, there are often one or more disconnects present:
The business is unable to define the desired outcome(s).
The developer has little understanding of what needs to be built. In other words, the needs of the business.
The business, in turn, has little understanding of the technical challenges associated with building the product.
Fundamentally, the disconnect is caused by a lack of communication. BDD seeks to bridge the communication gap between the business and the developer, resulting in products that deliver value, meet goals, and fulfill expectations.
In the next section, we will take a closer look at how this is achieved.
Indeed, developers who use BDD write acceptance criteria in a standard format that promotes clarity, easy integration, and automated testing.
These criteria consist of vocabulary that stakeholders, experts, and engineers can all understand and agree upon.
Acceptance tests should be written using common templates such as the “Given-When-Then” formula or the “Role-Feature-Reason” matrix.
Each test in turn should be based on a user story using ubiquitous language.
For example, software that processes loan applications should ideally have classes such as LoanApplication and Customer.
To further simplify the process, BDD incorporates domain-specific language (DSL) which uses English-like sentences to express both behaviors and desired outcomes.
Advantages of Behavior-Driven Development
A business that is planning to implement BDD should be aware of the list of potential advantages and disadvantages to its software team.
Better communication
This is perhaps the most obvious benefit of BDD, but extremely important in delivering value and increasing process efficiency.
Shorter learning curve
Since BDD uses simple language, the learning time is naturally reduced.
Increased reach
Another benefit of simple language is that it can reach a wider audience.
This promotes stakeholder engagement and fosters a sense of collaborative work toward a shared vision.
Discovery workshops
At the beginning of a project, BDD discovery workshops unearth additional capabilities and complexities.
Specifications are detailed and described in terms of application behavior, so edge cases and many of the finer details are identified early.
Ultimately, being aware of more scenarios initially leads to less rework during the later stages of the project.
Disadvantages of Behavior-Driven Development
Prior experience
Although the focus of BDD is on simplicity, it does assume that practitioners have some experience in Test Driven Development.
Incompatibility
The BDD methodology is incompatible with linear project management approaches such as the waterfall model.
Reliance on the Three Amigos
A critical component of BDD is the regular and collaborative nature of communication between the developer, tester, and business.
When one or more of the amigos is unwilling to devote the time or effort to communicate, the validity of user stories is compromised.
Behavior-driven development example
To appreciate how behavior-driven development may function in the real world, let’s look at an example of an automotive company that is developing a self-driving vehicle.
Specifically, the company is developing software that allows the vehicle to respond to speed limit restrictions.
The description of the behavior starts with a feature, capability, or story within the bounds of certain acceptance criteria.
Remember that all of these are defined with terms from the customer’s domain.
With that in mind, below is the user story and associated acceptance criteria as defined by the automotive company:
As a driver,
I wantthe vehicle to identify the posted speed limit and maintain its speed at that limit
So that I can avoid paying attention to the speed limit myself.
Acceptance criteria: the car maintains its speed near or at the speed limit, but never above it.
We can also write the acceptance criteria using the Given-Then-When (GWT) formula mentioned in a previous section:
Given a posted speed limit
When the vehicle is moving
Then it is near the speed limit but not above.
The company then finds that the GWT formula is a little too ambiguous to code the story.
To provide some clarity, one or more scenario examples are formulated to specify the details of the behavior and define an acceptance test.
For example:
Given the posted speed limit is 75 kph
When the vehicle is moving
Then its speed is between 73 and 75 kph.
Developer, tester, and business collaboration
The Three Amigos then collaborate and additional acceptance criteria and scenarios start to become apparent.
Suppose that one of these reads as follows: When the posted speed limit decreases, the vehicle’s speed decreases without excessive force.
The team can use the GTW formula once more to define an acceptance test that defines an approved rate of deceleration.
In other words:
Giventhe posted speed limit is 60 kph
When the posted speed limit decreases to 50 kph
Then the rate of deceleration should be less than 10 meters per second squared.
Note that a similar formula could be applied when the vehicle enters a motorway and is required to accelerate to the speed limit.
Once the vehicle is traveling at speed on the motorway, the automotive company decides that a more substantial rate of deceleration may be required as the vehicle approaches a tunnel.
The reasons for this are twofold.
For one, all tunnels have a posted speed limit of 90 kph. They also have a speed camera at their entrance which necessitates that the car traveling at a motorway speed of 120 kph must decelerate more quickly to avoid the driver receiving a fine.
Based on this, more acceptance criteria that detail the story’s requirements must be developed.
For example: When the vehicle approaches a motorway tunnel, it decelerates at an appropriate rate to avoid the driver receiving a speeding fine.
Of course, additional tests must be created to define the appropriate rate of deceleration.
Criteria and tests should also be developed to clarify the distance at which the vehicle starts to decelerate upon approaching the tunnel.
Key takeaways
Behavior-Driven Development is a means of increasing the collaboration between business people and technical people during agile software development.
Behavior-Driven Development encourages teams to use simple language and concepts to formalize a shared understanding of how an application should behave.
If implemented successfully, Behavior-Driven Development increases collaboration, communication, and increased reach. However, it does rely heavily on total commitment from each of the Three Amigos.
Key Highlights
Definition and Purpose:
Behavior-Driven Development (BDD) is a process that defines how software should behave in different scenarios.
It bridges communication gaps between business stakeholders and developers, ensuring that software meets goals and expectations.
Challenges Addressed:
BDD addresses disconnects in software development where the business can’t define outcomes, developers lack understanding of business needs, and technical challenges are misunderstood.
It overcomes these challenges by promoting effective communication and collaboration.
Implementing BDD Practices:
BDD combines elements of Test Driven Development (TDD) and Acceptance Test-Driven Development (ATDD).
Acceptance criteria are written in a standardized format for clarity, integration, and automated testing.
Common templates like “Given-When-Then” or “Role-Feature-Reason” are used for writing acceptance tests.
Ubiquitous Language and DSL:
BDD uses a domain-specific language (DSL) with English-like sentences to express behaviors and outcomes.
This DSL promotes shared understanding between stakeholders, experts, and engineers.
Advantages of BDD:
Better Communication: BDD improves communication between business and technical teams, increasing process efficiency and delivering value.
Shorter Learning Curve: The use of simple language reduces the time needed for understanding.
Increased Reach: Simplicity allows a wider audience to engage, fostering collaboration and shared vision.
Discovery Workshops: BDD workshops identify complexities early, leading to less rework in later stages.
Disadvantages of BDD:
Prior Experience: BDD assumes some familiarity with Test Driven Development.
Incompatibility: BDD is incompatible with linear project management approaches like the waterfall model.
Three Amigos Reliance: Effective BDD relies on collaboration between developer, tester, and business roles.
Behavior-Driven Development Example:
A self-driving vehicle software development example demonstrates BDD’s application.
User stories and acceptance criteria are written using customer domain terms for clarity.
The “Given-When-Then” formula and scenarios define behavior and acceptance tests.
Collaboration and Three Amigos:
BDD emphasizes collaboration between developer, tester, and business roles (Three Amigos).
Collaboration leads to clear acceptance criteria and scenarios that ensure software meets expectations.
AIOps is the application of artificial intelligence to IT operations. It has become particularly useful for modern IT management in hybridized, distributed, and dynamic environments. AIOps has become a key operational component of modern digital-based organizations, built around software and algorithms.
Agile started as a lightweight development method compared to heavyweight software development, which is the core paradigm of the previous decades of software development. By 2001 the Manifesto for Agile Software Development was born as a set of principles that defined the new paradigm for software development as a continuous iteration. This would also influence the way of doing business.
Agile Program Management is a means of managing, planning, and coordinating interrelated work in such a way that value delivery is emphasized for all key stakeholders. Agile Program Management (AgilePgM) is a disciplined yet flexible agile approach to managing transformational change within an organization.
Agile project management (APM) is a strategy that breaks large projects into smaller, more manageable tasks. In the APM methodology, each project is completed in small sections – often referred to as iterations. Each iteration is completed according to its project life cycle, beginning with the initial design and progressing to testing and then quality assurance.
Agile Modeling (AM) is a methodology for modeling and documenting software-based systems. Agile Modeling is critical to the rapid and continuous delivery of software. It is a collection of values, principles, and practices that guide effective, lightweight software modeling.
Agile Business Analysis (AgileBA) is certification in the form of guidance and training for business analysts seeking to work in agile environments. To support this shift, AgileBA also helps the business analyst relate Agile projects to a wider organizational mission or strategy. To ensure that analysts have the necessary skills and expertise, AgileBA certification was developed.
Agile leadership is the embodiment of agile manifesto principles by a manager or management team. Agile leadership impacts two important levels of a business. The structural level defines the roles, responsibilities, and key performance indicators. The behavioral level describes the actions leaders exhibit to others based on agile principles.
The andon system alerts managerial, maintenance, or other staff of a production process problem. The alert itself can be activated manually with a button or pull cord, but it can also be activated automatically by production equipment. Most Andon boards utilize three colored lights similar to a traffic signal: green (no errors), yellow or amber (problem identified, or quality check needed), and red (production stopped due to unidentified issue).
Bimodal Portfolio Management (BimodalPfM) helps an organization manage both agile and traditional portfolios concurrently. Bimodal Portfolio Management – sometimes referred to as bimodal development – was coined by research and advisory company Gartner. The firm argued that many agile organizations still needed to run some aspects of their operations using traditional delivery models.
Business innovation is about creating new opportunities for an organization to reinvent its core offerings, revenue streams, and enhance the value proposition for existing or new customers, thus renewing its whole business model. Business innovation springs by understanding the structure of the market, thus adapting or anticipating those changes.
Business modelinnovation is about increasing the success of an organization with existing products and technologies by crafting a compelling value proposition able to propel a new business model to scale up customers and create a lasting competitive advantage. And it all starts by mastering the key customers.
A consumer brand company like Procter & Gamble (P&G) defines “Constructive Disruption” as: a willingness to change, adapt, and create new trends and technologies that will shape our industry for the future. According to P&G, it moves around four pillars: lean innovation, brand building, supply chain, and digitalization & data analytics.
That is a process that requires a continuous feedback loop to develop a valuable product and build a viable business model. Continuous innovation is a mindset where products and services are designed and delivered to tune them around the customers’ problem and not the technical solution of its founders.
A design sprint is a proven five-day process where critical business questions are answered through speedy design and prototyping, focusing on the end-user. A design sprint starts with a weekly challenge that should finish with a prototype, test at the end, and therefore a lesson learned to be iterated.
Tim Brown, Executive Chair of IDEO, defined design thinking as “a human-centered approach to innovation that draws from the designer’s toolkit to integrate the needs of people, the possibilities of technology, and the requirements for business success.” Therefore, desirability, feasibility, and viability are balanced to solve critical problems.
DevOps refers to a series of practices performed to perform automated software development processes. It is a conjugation of the term “development” and “operations” to emphasize how functions integrate across IT teams. DevOps strategies promote seamless building, testing, and deployment of products. It aims to bridge a gap between development and operations teams to streamline the development altogether.
Product discovery is a critical part of agile methodologies, as its aim is to ensure that products customers love are built. Product discovery involves learning through a raft of methods, including design thinking, lean start-up, and A/B testing to name a few. Dual Track Agile is an agile methodology containing two separate tracks: the “discovery” track and the “delivery” track.
eXtreme Programming was developed in the late 1990s by Ken Beck, Ron Jeffries, and Ward Cunningham. During this time, the trio was working on the Chrysler Comprehensive Compensation System (C3) to help manage the company payroll system. eXtreme Programming (XP) is a software development methodology. It is designed to improve software quality and the ability of software to adapt to changing customer needs.
Feature-Driven Development is a pragmatic software process that is client and architecture-centric. Feature-Driven Development (FDD) is an agile software development model that organizes workflow according to which features need to be developed next.
A Gemba Walk is a fundamental component of lean management. It describes the personal observation of work to learn more about it. Gemba is a Japanese word that loosely translates as “the real place”, or in business, “the place where value is created”. The Gemba Walk as a concept was created by Taiichi Ohno, the father of the Toyota Production System of lean manufacturing. Ohno wanted to encourage management executives to leave their offices and see where the real work happened. This, he hoped, would build relationships between employees with vastly different skillsets and build trust.
GIST Planning is a relatively easy and lightweight agile approach to product planning that favors autonomous working. GIST Planning is a lean and agile methodology that was created by former Google product manager Itamar Gilad. GIST Planning seeks to address this situation by creating lightweight plans that are responsive and adaptable to change. GIST Planning also improves team velocity, autonomy, and alignment by reducing the pervasive influence of management. It consists of four blocks: goals, ideas, step-projects, and tasks.
The ICE Scoring Model is an agile methodology that prioritizes features using data according to three components: impact, confidence, and ease of implementation. The ICE Scoring Model was initially created by author and growth expert Sean Ellis to help companies expand. Today, the model is broadly used to prioritize projects, features, initiatives, and rollouts. It is ideally suited for early-stage product development where there is a continuous flow of ideas and momentum must be maintained.
An innovation funnel is a tool or process ensuring only the best ideas are executed. In a metaphorical sense, the funnel screens innovative ideas for viability so that only the best products, processes, or business models are launched to the market. An innovation funnel provides a framework for the screening and testing of innovative ideas for viability.
According to how well defined is the problem and how well defined the domain, we have four main types of innovations: basic research (problem and domain or not well defined); breakthrough innovation (domain is not well defined, the problem is well defined); sustaining innovation (both problem and domain are well defined); and disruptive innovation (domain is well defined, the problem is not well defined).
The innovation loop is a methodology/framework derived from the Bell Labs, which produced innovation at scale throughout the 20th century. They learned how to leverage a hybrid innovation management model based on science, invention, engineering, and manufacturing at scale. By leveraging individual genius, creativity, and small/large groups.
The Agile methodology has been primarily thought of for software development (and other business disciplines have also adopted it). Lean thinking is a process improvement technique where teams prioritize the value streams to improve it continuously. Both methodologies look at the customer as the key driver to improvement and waste reduction. Both methodologies look at improvement as something continuous.
A startup company is a high-tech business that tries to build a scalable business model in tech-driven industries. A startup company usually follows a lean methodology, where continuous innovation, driven by built-in viral loops is the rule. Thus, driving growth and building network effects as a consequence of this strategy.
As pointed out by Eric Ries, a minimum viable product is that version of a new product which allows a team to collect the maximum amount of validated learning about customers with the least effort through a cycle of build, measure, learn; that is the foundation of the lean startup methodology.
Kanban is a lean manufacturing framework first developed by Toyota in the late 1940s. The Kanban framework is a means of visualizing work as it moves through identifying potential bottlenecks. It does that through a process called just-in-time (JIT) manufacturing to optimize engineering processes, speed up manufacturing products, and improve the go-to-market strategy.
Jidoka was first used in 1896 by Sakichi Toyoda, who invented a textile loom that would stop automatically when it encountered a defective thread. Jidoka is a Japanese term used in lean manufacturing. The term describes a scenario where machines cease operating without human intervention when a problem or defect is discovered.
The PDCA (Plan-Do-Check-Act) cycle was first proposed by American physicist and engineer Walter A. Shewhart in the 1920s. The PDCA cycle is a continuous process and product improvement method and an essential component of the lean manufacturing philosophy.
RAD was first introduced by author and consultant James Martin in 1991. Martin recognized and then took advantage of the endless malleability of software in designing development models. Rapid Application Development (RAD) is a methodology focusing on delivering rapidly through continuous feedback and frequent iterations.
Retrospective analyses are held after a project to determine what worked well and what did not. They are also conducted at the end of an iteration in Agile project management. Agile practitioners call these meetings retrospectives or retros. They are an effective way to check the pulse of a project team, reflect on the work performed to date, and reach a consensus on how to tackle the next sprint cycle. These are the five stages of a retrospective analysis for effective Agile project management: set the stage, gather the data, generate insights, decide on the next steps, and close the retrospective.
Scaled Agile Lean Development (ScALeD) helps businesses discover a balanced approach to agile transition and scaling questions. The ScALed approach helps businesses successfully respond to change. Inspired by a combination of lean and agile values, ScALed is practitioner-based and can be completed through various agile frameworks and practices.
The SMED (single minute exchange of die) method is a lean production framework to reduce waste and increase production efficiency. The SMED method is a framework for reducing the time associated with completing an equipment changeover.
The Spotify Model is an autonomous approach to scaling agile, focusing on culture communication, accountability, and quality. The Spotify model was first recognized in 2012 after Henrik Kniberg, and Anders Ivarsson released a white paper detailing how streaming company Spotify approached agility. Therefore, the Spotify model represents an evolution of agile.
As the name suggests, TDD is a test-driven technique for delivering high-quality software rapidly and sustainably. It is an iterative approach based on the idea that a failing test should be written before any code for a feature or function is written. Test-Driven Development (TDD) is an approach to software development that relies on very short development cycles.
Timeboxing is a simple yet powerful time-management technique for improving productivity. Timeboxing describes the process of proactively scheduling a block of time to spend on a task in the future. It was first described by author James Martin in a book about agile software development.
Scrum is a methodology co-created by Ken Schwaber and Jeff Sutherland for effective team collaboration on complex products. Scrum was primarily thought for software development projects to deliver new software capability every 2-4 weeks. It is a sub-group of agile also used in project management to improve startups’ productivity.
Scrumban is a project management framework that is a hybrid of two popular agile methodologies: Scrum and Kanban. Scrumban is a popular approach to helping businesses focus on the right strategic tasks while simultaneously strengthening their processes.
Scrum anti-patterns describe any attractive, easy-to-implement solution that ultimately makes a problem worse. Therefore, these are the practice not to follow to prevent issues from emerging. Some classic examples of scrum anti-patterns comprise absent product owners, pre-assigned tickets (making individuals work in isolation), and discounting retrospectives (where review meetings are not useful to really make improvements).
Scrum at Scale (Scrum@Scale) is a framework that Scrum teams use to address complex problems and deliver high-value products. Scrum at Scale was created through a joint venture between the Scrum Alliance and Scrum Inc. The joint venture was overseen by Jeff Sutherland, a co-creator of Scrum and one of the principal authors of the Agile Manifesto.
Six Sigma is a data-driven approach and methodology for eliminating errors or defects in a product, service, or process. Six Sigma was developed by Motorola as a management approach based on quality fundamentals in the early 1980s. A decade later, it was popularized by General Electric who estimated that the methodology saved them $12 billion in the first five years of operation.
Stretch objectives describe any task an agile team plans to complete without expressly committing to do so. Teams incorporate stretch objectives during a Sprint or Program Increment (PI) as part of Scaled Agile. They are used when the agile team is unsure of its capacity to attain an objective. Therefore, stretch objectives are instead outcomes that, while extremely desirable, are not the difference between the success or failure of each sprint.
The Toyota Production System (TPS) is an early form of lean manufacturing created by auto-manufacturer Toyota. Created by the Toyota Motor Corporation in the 1940s and 50s, the Toyota Production System seeks to manufacture vehicles ordered by customers most quickly and efficiently possible.
The Total Quality Management (TQM) framework is a technique based on the premise that employees continuously work on their ability to provide value to customers. Importantly, the word “total” means that all employees are involved in the process – regardless of whether they work in development, production, or fulfillment.
The waterfall model was first described by Herbert D. Benington in 1956 during a presentation about the software used in radar imaging during the Cold War. Since there were no knowledge-based, creative software development strategies at the time, the waterfall method became standard practice. The waterfall model is a linear and sequential project management framework.
Gennaro is the creator of FourWeekMBA, which reached about four million business people, comprising C-level executives, investors, analysts, product managers, and aspiring digital entrepreneurs in 2022 alone | He is also Director of Sales for a high-tech scaleup in the AI Industry | In 2012, Gennaro earned an International MBA with emphasis on Corporate Finance and Business Strategy.
