March 27, 2017

Learning Serenity: Studying BDD using The Cucumber Book and BDD in Action

It’s been a productive two weeks here at Ahold in Quincy, MA. They are the the holding company for Stop & Shop, Giant Foods, and Martin’s, where I am testing mobile applications for the iPhone, iPad and Android.

Although I’m mostly focused on manual testing as I am attempting to get to know the business, I’ve been trying to get myself up to speed with the automation framework they are using, Serenity BDD. I have a long term goal of combining their current Serenity BDD test suite with Appium, so when we start developing a regression test suite, I can possibly automate it.

As I Tweeted a few days ago… Oh, this is going to take a while!


Hrm… thank you, Serenity BDD! I need to look into that.

Oh, and thank you very much, John Smart, for your words of encouragement on this blog series:


For now, since I am studying how to implement Serenity using a testing framework invented by Aslak Hellesoy called "Cucumber".


BDD and The Cucumber Book

For those who were wondering, the “BDD” in Serenity BDD stands for “Behavior Driven Development”. I first encountered BDD when I was supervising an offshore testing team attempting to translate my manual mobile test scripts into Cucumber / Ruby automation using Calabash-IOS. That is when I first encountered Matt Wynne’s “The Cucumber Book: Behaviour-Driven Development for Testers and Developers” (2012), which was quite helpful describing BDD.
Matt Wynne and Aslak Helles√ły [the creator of Cucumber] show you how to express your customers’ wild ideas as a set of clear, executable specifications that everyone on the team can read. You’ll learn how to feed those examples into Cucumber and let it guide your development. You’ll build just the right code to keep your customers happy, and not a line more. Although it was born in the Ruby community, you can use Cucumber to test almost any system, from a simple shell script or Perl script, to web applications written in PHP, Java, or any platform”. - The Cucumber Book, The Pragmatic Bookshelf 

About the Authors


Note: The Cucumber Book now a second edition, released on February 27, 2017.

Matt Wynne is a long-standing member of the Cucumber core team, fascinated by the challenge of helping tech and business to understand one another. He's one of the co-founders of Cucumber Ltd., the company behind Cucumber. He lives on the west coast of Scotland on an old farm with his family, two cats, their dog, and some ducks. Matt tweets from @mattwynne and @cucumberbdd.

Aslak Hellesoy is the creator of Cucumber. During his career Aslak has worked with both small and large organizations in industries such as telecom, trading, insurance, car manufacturing, education, and government. Aslak is a co-founder of Cucumber Ltd, the company behind Cucumber. He tweets from @aslak_hellesoy and @cucumberbdd.

"Steve Tooke is a programmer, trainer, and coach who is dedicated to improving his craft and helping others improve theirs. He's a co-founder of Cucumber Ltd. Steve tweets from @tooky and @cucumberbdd”.


Oh, and Why Is It Called "Cucumber"?

Why the name "Cucumber"? Read Aslak Hellesoy's answer on Quora, how he asked his fiancee, Patty for naming suggestions:

"Patty, I need a name for this new tool I just started hacking on. I want it to have a catchy, non-geeky sounding name.

"She paused for a few seconds, then said: Cucumber!

"And I thought: Cucumber? Really? Well, it's a lot better than Stories - so I'll go with that for now. I'll rename it again when I come up with something better".


What is an Acceptance Test for a Feature?


Here’s an example Matt Wynne lists in The Cucumber Book:

Feature: Sign up
     Sign up should be quick and friendly.
Scenario: Successful sign up
New users should get a confirmation email and be greeted personally by the site once signed in.
Given I have chosen to sign up
When I sign up with valid details
Then I should receive a confirmation email
And I should see a personalized greeting message

… This is an example of what is called an acceptance test. “Instead of a business stakeholder passing requirements to the development team without much opportunity for feedback, the developer and stakeholder collaborate to write automated tests that express the outcome that the stakeholder wants. We call them acceptance tests because they express what the software needs to do in order for the stakeholder to find it acceptable. The test fails at the time of writing, because no code has been written yet, but it captures what the stakeholder cares about and gives everyone a clear signal as to what it will take to be done”.

The Product Owner, a business analyst representing the customer’s wants and needs on an Agile Software Development project can express a client’s wishes and expectations in an easy-to-read format. They can be expressed in terms of behavior wanted in the finished product.

As Matt Wynne mentions, “Acceptance tests written in this style become more than just tests; they are executable specifications […]
“For many teams, they become the definitive source of truth as to what the system does. Having a single place to go for this information saves a lot of time that is often wasted trying to keep requirements documents, tests, and code all in sync. It also helps to build trust within the team, because different parts of the team no longer have their own personal versions of the truth”. - The Cucumber Book

How Do Features Get Turned Into Steps and Step Definitions?  

But how does it work?
“When you run [Cucumber], it reads in your specifications from plain-language text files called features, examines them for scenarios to test, and runs the scenarios against your system. Each scenario is a list of steps for Cucumber to work through. So that Cucumber can understand these feature files, they must follow some basic syntax rules. The name for this set of rules is Gherkin. Along with the features, you give Cucumber a set of step definitions, which map the business-readable language of each step into Ruby code to carry out whatever action is being described by the step. In a mature test suite, the step definition itself will probably just be one or two lines of Ruby that delegate to a library of support code, specific to the domain of your application, that knows how to carry out common tasks on the system. Normally that will involve using an automation library, like the browser automation library Capybara, to interact with the system itself”. - The Cucumber Book

Does Serenity BDD Still Use Features Files and Step Definitions? 


If you are using Serenity BDD with Cucumber, it will follow the same exact steps.

  • Narratives describe the story you want to tell.
  • Feature files describe the features of the product, breaking it down into scenarios outlining how the feature will be used.
  • Step definitions walk through step-by-step how to execute the code.

“Step definitions sit right on the boundary between the business’s domain and the programmer’s domain. […] Their responsibility is to translate each plain-language step in your Gherkin scenarios into concrete actions in […] code”.

What is the difference between Steps and Step Definitions?

“Each Gherkin scenario is made up of a series of steps, written in plain language. On its own, a step is just documentation; it needs a step definition to bring it to life. A step definition is a piece of Ruby code that says to Cucumber, ‘If you see a step that looks like this…, then here’s what I want you to do….’ When Cucumber tries to execute each step, it looks for a matching step definition to execute. So, how does Cucumber match a step definition to a step"
“Gherkin steps are expressed in plain text. Cucumber scans the text of each step for patterns that it recognizes, which you define using a regular expression. If you haven’t used regular expressions before, then just think of them like a slightly more sophisticated version of the wildcards you’d use to search for a file”. - The Cucumber Book

What is the Difference Between BDD and ATDD?

To answer this questions, let's jump to a sidebar in “BDD in Action” written by John Ferguson Smart, the creator of Serenity BDD.

BDD by any other name

“Many of the ideas around BDD are not new and have been practiced for many years under a number of different names. Some of the more common terms used for these practices include Acceptance-Test-Driven Development, Acceptance Test-Driven Planning, and Specification by Example. To avoid confusion, let’s clarify a few of these terms in relation to BDD.

Specification by Example describes the set of practices that have emerged around using examples and conversation to discover and describe requirements. In his seminal book of the same name,14 Gojko Adzic chose this term as the most representative name to refer to these practices. Using conversation and examples to specify how you expect a system to behave is a core part of BDD, and we’ll discuss it at length in the first half of this book.

Acceptance-Test-Driven Development (ATDD) is now a widely used synonym for Specification by Example, but the practice has existed in various forms since at least the late 1990s. Kent Beck and Martin Fowler mentioned the concept in 2000,15 though they observed that it was difficult to implement acceptance criteria in the form of conventional unit tests at the start of a project. But unit tests aren’t the only way to write automated acceptance tests, and since at least the early 2000s, innovative teams have asked users to contribute to executable acceptance tests and have reaped the benefits

Acceptance-Test-Driven Planning is the idea that defining acceptance criteria for a feature leads to better estimates than doing a task breakdown”.

What is the Goal of BDD?

“One of the key goals of BDD is to ensure that everyone has a clear understanding of what a project is trying to deliver, and of the underlying business objectives of the project. This, in itself, goes a long way toward ensuring that the application actually meets these objectives.
“You can achieve this by working with users and other stakeholders to define or clarify a set of high-level business goals for the application. These goals should provide a concise vision of what you need to build. Business goals are about delivering value, so it’s common to see them expressed in terms of increasing or protecting revenue, or of decreasing costs”. - BDD in Action

Now that the research has been done, we can start assembling a new Serenity BDD project..

Until then, Happy Testing!



-T.J. Maher
Twitter | LinkedIn | GitHub

// Sr. QA Engineer, Software Engineer in Test, Software Tester since 1996.
// Contributing Writer for TechBeacon.
// "Looking to move away from manual QA? Follow Adventures in Automation on Facebook!"
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