behaviour driven development - cuking the agile world

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India Agile Week-201326-Oct-2013 at Pune

BDD in an Agile world

Gaurav Awasthi

Senior Architect and Technology Evangelist

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www.unicomlearning.comConcept, Practice, Tools

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India Agile Week-2013

Concept, Practice and finally Tools

Concepts are beyond Practices and Tools

Good Tools are better suited to Practices which help internalize Concepts quickly





www.unicomlearning.comThe BDD World…

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Concepts Write software that matters In close collaboration with Stakeholder

Practices Writing features, scenarios Write executable specs

Tools Cucumber JBehave RSpecs





www.unicomlearning.comBDD…by definition

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BDD is a second-generation, outside-in, multiple-stakeholder, high-automation, agile methodology.

It describes a cycle of interactions with well-defined outputs, resulting in the delivery of working, tested software that matters.

Dan North





www.unicomlearning.comBuzzword Agnostic Benefits…

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• Seamless mapping between Requirement statements and executable tests

• Specification by example

• Loose grammar of the domain

• Brings Testers/QA to the forefront of development process

• Self verifying documentation

• Evolves behavior as the domain understanding changes





www.unicomlearning.comCo-existence with TDD

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TDD

Write a failing unit test Make the

test pass

Refactor

BDD

Write a failing feature test

TDD – Develop it the right way

BDD – Develop the right thing





www.unicomlearning.comAnd what about DDD ?

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• Domain Driven Design • Ubiquitous Language• gives vocabulary• Inside Out

• Behavior Driven Development• Sentences out of the vocabulary• Description of the behavior• Outside In





www.unicomlearning.comThe BDD Practice

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1. Describe the behavior in plain text – Features and Scenarios

2. Write a step definition for each Step

3. Run it and watch it fail

4. Write code to make the step pass

5. Run it again and see the step pass

6. Repeat step 2 – 5 until green like a Cuke

7. Repeat step 1 – 6 until the money runs out





www.unicomlearning.comThe Tool - Cucumber

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Why Cucumber ?

• one of the least technical tools

• a very active open source project

• supports a variety of languages






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• JBehave -> ported to Ruby -> RBehave -> rewritten from scratch -> RSpec -> + story runner -> Cucumber -> Cucumber-JVM

• Aslak Hellesoy ported Cucumber to Java (cucumber-jvm)

• Cucumber comes with Ruby (the original), Java, .NET, Adobe Flex, Python, Perl, Erlang, PHP

• Full stack for acceptance tests include – Browser Driver and Browser

Slicing Cucumber





www.unicomlearning.comGherkin

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• A Business Readable, Domain Specific Language that Cucumber understands

• Line-based language that Cucumber uses to define behaviors in the form of features, scenarios, and steps

• Serves 3 purposes :• Automated Tests• Documentation• Specs for Code to be written

• Source files have .feature extension. Single Gherkin source file contains a description of a single feature





www.unicomlearning.comGherkin syntax Feature : title

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As a [ person or role who will benefit ]

I want [ some feature ]

So that [ benefit or value of the feature ]





www.unicomlearning.comGherkin syntax Scenario : title

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Given [ some initial context ]

When [ an event occurs]

Then [ ensures some outcome ]





www.unicomlearning.comExample

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Feature: Customer purchases a device

• As a Customer• I want to purchase a Bluetooth

device• So that I can make or receive a

hands free call

Scenario : Customer has a credit note valued more than the receipt amount

• Given the customer is on the till

• And he has a credit note of Rs 1000

• And the receipt amount is Rs 500

• When the balance amount is paid

• Then the billing completes





www.unicomlearning.comCucumber Options

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@RunWith(Cucumber.class) @Cucumber.Options (

tags = “@focus”,features= “classpath:billing.feature”

) public class CukeRunner { }

Some common options : • features – path to the feature files• glue – where to look for step definition and hooks• tags – what tags in the features should be executed• format – what formatters to use• …





www.unicomlearning.comCLI Option

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• Several Runners• Command Line Interface cucumber-core• JUnit Runner cucumber-junit• Android Runner cucumber-android

• java cucumber.cli.Main [options] [FILE|DIR]• --glue , --format, --tags, --name …

• Benefit :• Independent of JUnit• Integration with Ant





www.unicomlearning.comDemo Code

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• Create a maven project, with cucumber-jvm related dependencies

• cucumber-core, cucumber-java, cucumber-junit• Write a Feature and a scenario with steps

• Feature: Withdrawing money from a User account• Scenario: Withdrawing money from a User's account should

reduce money in the current balance• Given a User has $100 in his account• When $50 is withdrawn from the account• Then the balance should be $50

• Write Java wrapper class – like CukeRunner, • annotated with RunWith and Cucumber.Options

• Run the class, let it fail• Implement Steps, Run again• See it green like a cuke





www.unicomlearning.comAnd the debate

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To TDD, To BDD or

To prefer one over the other





www.unicomlearning.comReferences

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• That's not BDD, that's just Cucumber by Chris Parsons• Introducing BDD by Dan North• http://dannorth.net/whats-in-a-story/ by Dan North• http://cukes.info/install-cucumber-jvm.html• http://cukes.info/api/cucumber/jvm/javadoc/cucumber/api/junit/

Cucumber.Options.html






THANK YOU

India Agile Week-2013Organized by

UNICOM Trainings & Seminars Pvt. Ltd. [email protected]

Speaker name: Gaurav AwasthiEmail ID: [email protected]





behaviour driven development - cuking the agile world

Technology

dan north http

india agile week

step definition

withdrawing money

receipt amount

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scenario

features