behavior-driven-development

Behavior-Driven Development In A Nutshell

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.

Understanding Behavior-Driven Development

During the software development process, there are often one or more disconnects present:

  1. The business is unable to define the desired outcome(s).
  2. The developer has little understanding of what needs to be built. In other words, the needs of the business.
  3. 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.

Implementing BDD practices

BDD is an approach that incorporates elements of Test Driven Development (TDD) and Acceptance Test-Driven Development (ATDD). 

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 and disadvantages 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.

Advantages

  • 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

  • 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 want the 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:

Given the 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.

Connected Agile Frameworks

AIOps

aiops
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 Methodology

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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 Project Management

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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

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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

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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.

Business Model Innovation

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Business model innovation 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.

Continuous Innovation

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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.

Design Sprint

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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.

Design Thinking

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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

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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.

Dual Track Agile

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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.

Feature-Driven Development

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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.

eXtreme Programming

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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.

Lean vs. Agile

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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.

Lean Startup

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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.

Kanban

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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.

Rapid Application Development

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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.

Scaled Agile

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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.

Spotify Model

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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.

Test-Driven Development

test-driven-development
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

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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

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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.

Scrum Anti-Patterns

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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

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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.

Read Also: Business Models Guide, Sumo Logic Business Model, Snowflake

InnovationAgile MethodologyLean StartupBusiness Model InnovationProject Management.

Read Next: SWOT AnalysisPersonal SWOT AnalysisTOWS MatrixPESTEL

Read Next: Business AnalysisCompetitor Analysis, Continuous InnovationAgile MethodologyLean StartupBusiness Model InnovationProject Management.

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