Specification-By-Example with Gherkin

FROM STAKEHOLDER EXAMPLES TO LIVING DOCUMENTATION

Specification-By-Example with Gherkin

Christian Hassa - [email protected] - Twitter: @chrishassaGoTo Night Zurich, June 12th 2014

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2000 2009

2010

2007

Scrum

1997

1992 2014

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User Story life-cycleIdea

Need

Problem

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Impact Mapping

Story Mapping

Specification-By-Example

Why?Outcomes

SpecificationsHow?

AcceptanceCriteria

Epics

Deliverables

Impacts

earlier later

User Activities

User Stories

Examples

Goals

Agile Product Ownership

Code

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EvolvingUser Stories

intoSpecifications

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Impact Mapping

Story Mapping


Why?Outcomes

SpecificationsHow?

AcceptanceCriteria

Epics

Deliverables

Impacts

earlier later

User Activities

User Stories

Examples

Goals

Specifying user stories

Code

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Why?Outcomes

SpecificationsHow?

Epics

Deliverables

Impacts

earlier later

User Activities

User Stories

Goals

Specifying user stories

Code

Reminderfor aconversation

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Having a conversation …

public void TestInitialOrderDiscount()

{

Customer newCustomer = new Customer();

Order newOrder = new Order(newCustomer);

newOrder.AddBook(

Catalog.Find(“ISBN-0955683610”)

);

Assert.Equals(33.75,

newOrder.Subtotal);

}

Register as “bart_bookworm”Go to “/catalog/search”Enter “ISBN-0955683610”Click “Search”Click “Add to Cart”Click “View Cart”Verify “Subtotal” is “$33.75”

We would like to encourage new users to buy in our shop.Therefore we offer 10% discount for their first order.

Original idea for the illustration: George Dinwiddiehttp://blog.gdinwidiee.com

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Why?Outcomes

SpecificationsHow?

AcceptanceCriteria

Epics

Deliverables

Impacts

earlier later

User Activities

User Stories

Examples

Goals

Establishing a shared understanding

Code

Bugreports

Isolated,formalizedexamples

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Specification-by-ExampleExamples …• make abstract descriptions

better understandable

However …• examples are usually not formally

exchanged or documented

Brian Marick

Examples Tests

Requirements

consist of

describe verifyfulfillment of

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Discussing acceptance criteria …

public void TestInitialOrderDiscount()

{

Customer newCustomer = new Customer();

Order newOrder = new Order(newCustomer);

newOrder.AddBook(

Catalog.Find(“ISBN-0955683610”)

);

Assert.Equals(33.75,

newOrder.Subtotal);

}

Register as “bart_bookworm”Go to “/catalog/search”Enter “ISBN-0955683610”Click “Search”Click “Add to Cart”Click “View Cart”Verify “Subtotal” is “$33.75”



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… illustrated with formalized examples

Given the user has not ordered yet

When the user adds a book with the price of EUR 37.5

into the shopping cart

Then the shopping cart sub-total is EUR 33.75.



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Discover hidden assumptions

Actually, this is not quite right:Books on sale should be excluded.


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Collaboration: 3 amigos

“HappyPath”

Technical feasability

Exceptions, border cases


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Structuringthe conversation

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Collecting Acceptance Criteria

“I would try to put a book into the shopping cart …”

“I would try to remove a book from the shopping cart…”

“I’d check whether the shopping cart is empty, when I enter the shop …”

Books can be added to shopping cart.

Books can be removed from shopping cart.

Shopping cart should be empty when entering the shop.

... ? …

As a potential customerI want to collect books in a shopping cartSo that I can order several books at once.

“Imagine this story is already implemented:

How would you verify it?”

“I would try to add 1000 books to the shopping cart …”

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Exploration through examples

Books in catalogue:

Title Author

Specification-By-Example Gojko Adzic

Impact Mapping Gojko Adzic

Explore It! Elisabeth Hendrickson

Competitive Engineering Tom Gilb

… I want to find books in the catalogue by author and title

Search for … Books found …

Spec Specification-By-Example

Hend Explore It!

et Explore It!, Competitive Engineering

Context

ActionAssertion

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Key examples: Breaking the model

Books in catalogue:

Title Author

Specification-By-Example Gojko Adzic

Impact Mapping Gojko Adzic

Explore It! Elisabeth Hendrickson

Competitive Engineering Tom Gilb

… I want to find books in the catalogue by author and title

Search for … Books found …

Spec Specification-By-Example

Hend Explore It!

et Explore It!, Competitive Engineering

What happens, if I search for “Explore Specification”?

Can I search for single characters, e.g. “e”?

Is the number of search results limited, or paged?

Is the search also performed in the sub-title of a book?

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UI wire frames,existing UI

rules, key examples

existing artifacts,samples

Different kinds of examples

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Abstract acceptance criteria

As a shop visitorI want to collect books in my shopping basketso that I can purchase multiple books at once.

Books can be added to the shopping basket

Books can be removed from the shopping basket

Shopping basket is initially empty

The same book can be added multiple times to the shopping basket

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Examples in Gherkin



Given my shopping basket is empty

When I add the book “Harry Potter” to my shopping basket

Then my shopping basket should contain 1 copy of “Harry Potter”

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Examples in Gherkin

Given my shopping basket contains 1 copy of “Harry Potter”


Then my shopping basket should contain 2 copies of “Harry Potter”


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Structure of examples




Title: Describes intention/abstract acceptance criterion

Arrange: Context, describes state of the system

Act: Execution of the feature

Assert: Assertion of observable behaviour

And I should see the warning: “Book already existed in basket”

Triple-Aconstraint“Checks”

Chainingup steps

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Purpose of the examples

• Shared understanding:acceptance criteria

•Documentation:system details

• Regression-tests:violated specifications

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Automated continuous validation




System

„Step Definitions“ are binding individual stepsto an automatable interface of the application.

Automatableinterface

UIAutomation

Automation does not necessarily have to bind to the UI.

Automatability of system is supported/evolving with development.

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Demo

http://www.specflow.org

Gherkin automation for .NET• Visual Studio plugin (VS-Gallery)•NuGet Package

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Booking system

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Payroll calculation

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eVoting system

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Examples in Excel

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Business readableteam flowwith ATDD

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Tasks are not business readable

Create bookings for a fixed time loop on

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… but scenarios (AC) are

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ATDD cycle

Write afailing

unit test

Make thetest pass

Refactor

Write a failingacceptance

test

Deploy andmeasureimpact

Refine feature, if needed(new user story)

break downunits

extendsystemUser Story

AC/Scenario 1

AC/Scenario 2

AC/Scenario …

AC/Scenario n

modifysystem

Expectedimpact

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Business readable progress

In Progress

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Current sprint report: all sprint scenarios

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Starting with first scenario (AC)

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Finishing the first scenario (AC)

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Progressing scenario after scenario

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Implementing user stories in parallel

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First user story ready for testing

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Testing can start even earlier

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Already done work can break again

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Already done work can break again

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See what is temporarily not working

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Livingdocumentation

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Living documentation

Drill into Details(Gherkin scenarios)

Overview(Story Map)

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User Stories vs. Features

Product/Sprint Backlog

User Story 1AccCrit 1

AccCrit 2

User Story 2AccCrit 3

AccCrit 4

Living Documentation

Feature 1

AccCrit 1

AccCrit 2

Feature nAccCrit 4

AccCrit mUser Story n

AccCrit 5

AccCrit m

AccCrit 3AccCrit 5

„Done“

• Future options of the system• Organized/refined according to

priority, value, effort, risk, ...• Next possible increments of

the product (units of work)

• Current state of the system• Organized/refined for

functional overview• Versioned and maintained

together with source code

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Gettingstarted with


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Start with the conversation

• What happens when … ?• What would you try out … ?• Discuss based on concrete examples

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Grow your team’s skills

• (Acceptance) Test Driven Development• Test Automation Pyramid• Exploratory Testing

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Decide for an automation toolGherkin tools available for Ruby, Java, .NET, JavaScript, PHP, …

www.specflow.org

www.cukes.info

Other ATDD tools like:JBehave, Fitnesse, Robotframework,Concordion, …

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Treat test automationas a first class citizen

• Emerging architecture• Refactoring•Definition of Done

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Books to read

Gojko AdzicBridiging theCommunication Gap

Gojko AdzicSpecification byExample

Elisabeth HendricksonExplore IT!

Coaching

69 Christian Hassa: [email protected] - @chrishassa

Specification-By-Example with Gherkin

Technology

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