Specification-By-Example with Gherkin
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FROM STAKEHOLDER EXAMPLES TO LIVING DOCUMENTATION Specification-By-Example with Gherkin Christian Hassa - [email protected] - Twitter: @chrishassa Swiss Requirements Day 2013, June 19th 2013
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Presentation held on Swiss Requirements Day 2013 in Zurich Many teams struggle with the implementation of user story acceptance criteria and establishing a shared understanding about the expected story outcomes. This results in missed stakeholder expectations and ad-hoc assumptions made by the team. High efforts for regression testing and the lack of a reliable documentation about the current system behavior are further problems resulting from an unstructured approach to define and validate acceptance criteria. In this session, you will learn how specification-by-example addresses these problems and overall increases the level of clarity on the project end-to-end. The presentation will cover the theory and practical experience from real projects, with concrete implementation examples based on the Gherkin specification language, that can be used for automated specification validation (available for .NET, Java, Ruby, PHP, JavaScript). You will leave this session with a fundamental understanding of specification-by-example and its benefits, as well as concrete pointers on how to get started using it in your own projects.
Transcript of Specification-By-Example with Gherkin
FROM STAKEHOLDER EXAMPLES TO LIVING DOCUMENTATION
Specification-By-Example with Gherkin
Christian Hassa - [email protected] - Twitter: @chrishassaSwiss Requirements Day 2013, June 19th 2013
TechTalk Team
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•Describe user needs or features•Unit of planning/prioritization
Help to say “Not now” – instead of “No”• Future options for evolving the system• Reminder for a conversation• Deferring detail to the
last responsible moment
What makes user stories agile?
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RefiningUser Stories
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Impact Mapping
Story Mapping
Specification-By-Example
Establishing a shared understandingWhy?
How?Code
Epics
Deliverables, Outputs
Impacts, Outcomes
Easier to define upfront Harder to define upfront
User Activities
User Stories
Goals
AcceptanceCriteria
Bugreports
Isolated,formalizedexamples
Examples
Reminderfor aconversation
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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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Usingexamples
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UI wire frames,existing UI
rules, key examples
existing artifacts,samples
Different models of examples
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Discussing examples …
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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Specification-by-Example
Examples …• make abstract descriptions
better understandable
However …• examples are usually not formally
exchanged or documentedBrian Marick
Examples Tests
Requirements
consist of
describe verifyfulfillment of
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Exploring a user need with 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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Discussion of 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”
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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… 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.
Original idea for the illustration: George Dinwiddiehttp://blog.gdinwidiee.com
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Discover hidden assumptions
Actually, this is not quite right:Books on sale should be excluded.
Original idea for the illustration: George Dinwiddiehttp://blog.gdinwidiee.com
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Collaboration: 3 amigos
“HappyPath”
Technical feasability
Exceptions, border cases
Original idea for the illustration: George Dinwiddiehttp://blog.gdinwidiee.com
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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
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
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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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
Examples in Gherkin
Given my shopping basket contains 1 copy of “Harry Potter”
When I add the book “Harry Potter” to my shopping basket
Then my shopping basket should contain 2 copies of “Harry Potter”
The same book can be added multiple times to the shopping basket
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The same book can be added multiple times to the shopping basket
Structure of examples
Given my shopping basket contains 1 copy of “Harry Potter”
When I add the book “Harry Potter” to my shopping basket
Then my shopping basket should contain 2 copies of “Harry Potter”
Title: Describes intention/abstract acceptance criterion
Arrange: Context, initial 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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Life time of
examples
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Purpose of the examples
• Shared understanding:acceptance criteria
•Documentation:system details
• Regression-tests:violated assumptions
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Continuous validation with automation
Given my shopping basket contains 1 copy of “Harry Potter”
When I add the book “Harry Potter” to my shopping basket
Then my shopping basket should contain 2 copies of “Harry Potter”
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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Livingdocumentation
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Living documentation
Drill into Details(Gherkin scenarios)
Overview(Story Map)
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Summary
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Conclusions
• Examples• Illustrate abstract requirements• Trigger new questions: collaborative discovery• Shared understanding
• Living documentation• Automatically validated examples• Business readable regression tests• Reliable source of truth
• Gherkin based automated examples• Open source, cross-platform• Requirement details versioned with source code• Similar tools: Fit/Fitnesse, Robot Framework, JBehave
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Gherkin based automation tools
www.cukes.info
www.behat.org
Ruby, Java, JavaScript, C++
www.specflow.org
.NET, Mono, Silverlight, WP7
PHP
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Books
Gojko AdzicBridiging theCommunication Gap
Gojko AdzicSpecification byExample
Elisabeth HendricksonExplore IT!
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47 Christian Hassa: [email protected] - @chrishassa
