Copyright © 2012 Accenture All rights reserved. 1 Living Requirements using Behavior Driven Development May 8, 2015

Copyright © 2012 Accenture All rights reserved. 1

Living Requirements using Behavior Driven DevelopmentMay 8, 2015

http://www.linkedin.com/in/martybradley

http://www.google.com/url?sa=i&rct=j&q=&esrc=s&frm=1&source=images&cd=&cad=rja&uact=8&docid=rHxUU8tF5JDW-M&tbnid=dhWe4ZKUzha1dM:&ved=0CAUQjRw&url=http://www.stltoday.com/news/new-mississippi-river-bridge-opens-to-traffic/article_110b6c60-6dd4-5760-ad31-3ba2f22107d5.html&ei=25R7U96HGZe3yATFmoD4AQ&bvm=bv.67229260,d.aWw&psig=AFQjCNHjlxYku77uOL25y6X1C0_7i0hgpA&ust=1400694361509494

Copyright© 2014 Accenture All rights reserved. 2

• Behavior-Driven Development (BDD)– What is it?– What are the benefits?– Who participates?

• Rhythm of BDD– How does it fit in the agile process?

• Gherkin language to create living requirements– How do we define system behavior?

• BDD Live Demo

Outline


• Behavior-Driven Development (BDD) is a disciplined technique for building software in which the Product Owner, a Programmer, and a Tester collaborate on system behavior, also known as, acceptance criteria for the feature that is about to implemented

Behavior-Driven DevelopmentWhat is BDD?


• Behavior-Driven Development (BDD) is a disciplined technique for building software in which the Product Owner, a Programmer, and a Tester collaborate on system behavior, also known as, acceptance criteria for the feature that is about to implemented

Behavior-Driven DevelopmentWhat is BDD?

A.K.A.• Acceptance Test Driven Development• Specification by Example• Story Testing• Functional Testing


Behavior-Driven Development

SHARED UNDERSTANDING

The biggest challenge in software development is to understand what the customer REALLY needs, in detail.

Behavior-Driven Development (BDD) encourages creating a shared understanding and collaboration by writing simple, scenario-based, single-source, living specifications that business people and IT people can read, easily understand, and quickly agree to that provides clear traceability.

We use a special text syntax called Gherkin to build scenarios…

GIVEN <condition>

WHEN <action>

THEN <result>

AUTOMATED TESTING

The most difficult part of DONEness is to ensure that your story has been fully tested so that it satisfies everything the Product Owner asked for and works when integrated with the rest of the product.

Using a tool called Cucumber, the previously written specifications can actually be turned into executable tests.

Thus, the language of our shared understanding becomes the language of our tests as well.

LIVING SPECIFICATION

Shared Understanding Made into Automated Tests



SHARED UNDERSTANDING

The biggest challenge in software development is to understand what the customer REALLY needs, in detail.

Behavior-Driven Development (BDD) encourages creating a shared understanding and collaboration by writing simple, scenario-based, single-source, living specifications that business people and IT people can read, easily understand, and quickly agree to that provides clear traceability.

We use a special text syntax called Gherkin to build scenarios…

GIVEN <condition>

WHEN <action>

THEN <result>

AUTOMATED TESTING

The most difficult part of DONEness is to ensure that your story has been fully tested so that it satisfies everything the Product Owner asked for and works when integrated with the rest of the product.

Using a tool called Cucumber, the previously written specifications can actually be turned into executable tests.

Thus, the language of our shared understanding becomes the language of our tests as well.

LIVING SPECIFICATION

Shared Understanding Made into Automated Tests

It’s Alive!

It’s ALIVE!


• Feature

• Background

• Scenario

• Given

• When

• Then

• And

• But

• *

• Scenario Outline

• Examples

The Building Blocks to Agile Scrum Software Development

Given (Context or Event)

When (User Action)

Then (Outcome)

Gherkin


Consumed by Cucumber

• Originally Ruby

• Cucubmer-JVM (java)

• Specflow (.NET)

The Building Blocks to Agile Scrum Software Development

Given (Context or Event)

When (User Action)

Then (Outcome)

Gherkin


• Like Test-Driven Development (TDD) but with Different Scope– Test from the “outside-in”– TDD fails when algorithm doesn’t exist (inside-out)– Executable specification fails because a feature doesn’t

exist– Helps teams build the right software product,

complementing technical practices that ensure that the product is built right



• Seems clear, but is it?– Customer should be prevented from entering invalid

credit card information

• Much more definitive– If a customer enters a credit card number that isn’t

exactly 16 digits long, when they try to submit the form, it should be redisplayed with an error message advising them of the correct number of digits.

An Example

The Cucumber Book, Matt Wynne & Aslak Hellesoy


• System Behavior – The system behavior is defined by a group of

scenarios that let you quickly add slices of functionality to help learn about the feature and it’s affect throughout the system

• Safety Net– The behavioral tests act as a safety net that

allows us to make functional and structural improvements to the code more freely without introducing bugs

• First “User”– The tests act as the first “User” of the code. This

results in code that is more easily reusable

Rhythm of BDD


• Usability– System functionality is more

deliberate– Developer is placed into the

paradigm of a user of the system– Fewer defects

• Live Documentation– Living specifications– Tests describe the behavior of the

system

Benefits of BDD


• Higher Code Quality– Testable code tends to follow better design

patterns• Modularized• Flexible• Understandable

– Testable code tends to have fewer lines

• Confidence– Tests cover smaller, incremental slices of the

system making it easier to pivot or grow a feature

– Tests act as a safety net covering existing functionality

Benefits of BDD


• Faster Delivery– Tests allow new features to be added more easily without

breaking existing ones– Misunderstanding of requirements appear earlier in the

development cycle and are more quickly eliminated – less time debugging.

Benefits of BDD


• Gherkin defines example Scenarios in a Given-When-Then format to create structure around the behaviors so that they can be automated

• Gherkin gives us a lightweight structure for documenting examples of the behavior our stakeholders want, in a way that it can be easily understood both by the stakeholders and by Cucumber

• Gherkin only has a few keywords allowing the team to build a domain specific language (DSL) for common use in the system and in conversations to promote a shared understanding

• Gherkin uses user defined tags to organize scenarios – @fast, @overnight, @web

Behavior-Driven DevelopmentLiving Specifications with the Gherkin Language


Feature discussion with PO

Me Likey Huh?

OUTSIDE-IN INSIDE-OUT

A Basic Example using Gherkin: Check inbox

Scenario: Check inbox

Given a User "Dave" with password "password”

And a User "Sue" with password "secret"

And an email to "Dave" from "Sue"

When I sign in as "Dave" with password "password"

Then I should see 1 email from "Sue" in my inbox

Example from The Cucumber Book, Matt Wynne & Aslak Hellesoy

This scenario is good but has a lot of detail that makes it hard to read



Given a User "Dave"

And a User "Sue"

And an email to "Dave" from "Sue"

When I sign in as "Dave"


Let’s get rid of the incidental details, the password in this case.




Given I have received an email from "Sue"

When I sign in


Let’s remove even more noise. This is very readable and easy to maintain


That’s exactly what I meant!! What a great scenario.

I’m a great Product Owner!

David Gijsbers, Eliassen Group


• Iteration 1: PO creates user story and bulleted acceptance criteria

• Iteration 2: 3 Amigos groom the story adding Given…When…Then scenarios

• Iteration 3: Developer & tester work the story using cucumber to generate the automation framework. They use the red-green-refactor cycle to design, develop, and test the feature

Note: Other artifacts can and should be attached to the user story such as, design documents, emails, or anything else that helps clarify the intent of the user story

Lifecycle of a User Story


Marty Bradley

www.bradasphere.com

www.linkedin.com/in/martybradley


A disciplined technique for building software in which the Product Owner, a Programmer, and a Tester collaborate on system behavior


• Cucumber-JVM is a native Java implementation of Cucumber

• Specflow is a .NET implementation of Cucumber

• https://cukes.info/ - Cucumber main

• https://cucumber.pro/ - Online collaboration version

• http://bradasphere.com/ - My blog containing some BDD videos

Some Tools and Helpful Links

https://cukes.info/

https://cukes.info/

https://cucumber.pro/

https://cucumber.pro/

http://bradasphere.com/

http://bradasphere.com/

Documents

Copyright © 2012 Accenture All rights reserved. 1 Living Requirements using Behavior Driven Development May 8, 2015