What is BDD?

Behavior-driven development (BDD) helps connect software development with business goals.

PublishedMarch 26, 2022

•2 min read

Software Engineer

BDD Tl;dr

BDD or behavior-driven development puts developers in the seat of business owners, forcing them to think about how their code creates value.

What is BDD?

BDD requires that units of software should be defined in terms of the desired behavior. Often the desired behavior is related to some business value requirement. BDD is a common practice in the agile development process.

BDD focuses more on defining how software should function. Behavior-driven development emerged from test-driven development which is more focused on testing code.

The Rules of BDD

BDD often follows one of two formats. The "given-when-then" format or the "as a blank I want blank so that blank." For example,

Given a user has properly filled out the form when they click the finish button then they should see a thank you message.
As a data analyst, I want form validation so that bad values don't make it to the database.

A popular way of implementing BDD using programming is through testing with Cucumber and Gherkin.

Pros of Behavior-Driven Development

BDD is defined through simple one-sentence outlines of behavior making it easy to understand.
BDD "given-when-then" and "as a blank I want blank so that blank" formats are non-technical so they can reach a large audience.
Behavior-driven development creates a common language for developers, testers, and business owners.

Cons of Behavior-Driven Development

Requirements in BDD have to be specific enough that developers can implement them.
Automated testing of behaviors with the BDD framework can require additional maintenance.

Comments (1)

Join the discussion

Miki Szeles4y ago

Great post Sean. 👏

When I first met BDD I imediatell fell in love with it.

Nowadays I am not using BDD as it adds one extra layer of complexity which result in a much higher maintenance cost.

One of the biggest USP of BDD is that managers can understand it too. In reality they will never check it.

There is one exception: Karate DSL for API testing. Because you only have to write plain English(Gherkin) as all the requests and assertions are implemented in the framework itself. 😊

Sean Coughlin4y ago

Hi Miki, thanks for the response!

The maintenance costs can be tough and I’ve personally been involved in some grueling updates to broken Cucumber tests. It’s not an experience I’d recommend.

I think the way BDD makes you think about code is helpful. I believe even if you aren’t creating BDD tests it can still help you reason in a more effective way.

Miki Szeles4y ago

I totally agree with you Sean Coughlin.

I only wanted to write that you can have BDD style code without adding one extra layer of complexity. 😊