This document discusses Behavior Driven Development (BDD) using the Ruby programming language. It provides an overview of test-driven development (TDD), then defines BDD as building upon TDD by formalizing good TDD habits like working outside-in from business goals. Gherkin is introduced as the language used for writing Cucumber features, using examples to clarify requirements. Cucumber is a tool for running automated acceptance tests written in a BDD style using Gherkin. It also discusses using Capybara to access and interact with web pages in tests.

1. BDD with
Ruby
Gherkin
Cucumber
Capybara
Gabi Kis
TDT - July 3, 2013

2. Agenda
• TDD
• BDD
• Gherkin
• Cucumber
• Capybara
• Demo (Ruby)
• Conclusions

3. What is TDD?
• Test-driven
development
(TDD)
o developer writes an
automated test case
o then produces the
minimum code to pass
test
o refactors the code to
acceptable standards

4. TDD
• Advantages:
o Programmers tend to be
more productive
o Can drive the design of a
program
o Offers the ability to take
small steps
o Can lead to more
modularized, flexible, and
extensible code
• Shortcomings
o Reliance on unit tests might
=> not perform sufficient full
functional testing
o Tests may share the same
blind spots with the code
o Tests become part of the
maintenance overhead of a
project
o Rewrite the tests when
requirements change

5. What is BDD?
• “BDD builds upon TDD by formalizing the good
habits of the best TDD practitioners.”
- Matt Wynne
• So what are those good habits?
o Working outside-in, starting from a business or organizational goal
o Using examples to clarify requirements
o Developing and using a ubiquitous language

6. BDD - Gherkin
Story card
Acceptance criteria
User story
As a <role>
I want to <feature>
So that <benefit>
Scenario
Given <initial context>
When <event occurs>
Then <ensure some outcomes>
Example:
Feature: Customer withdraws cash
As a customer,
I want to withdraw cash from an ATM,
So that I don’t have to wait in line at the bank
Scenario: Account is in credit
Given the account is in credit
And the card is valid
And the dispenser contains cash
When the customer requests cash
Then ensure the account is debited
And ensure cash is dispensed
And ensure the card is returned
Scenario: Account is overdrawn past overdraft limit
Given the account is overdrawn
And the card is valid
When the customer requests cash
Then ensure a rejection message is displayed
And ensure cash is not dispensed
And ensure the card is returned

7. Gherkin exercise
Feature: [ ]
In order to [ ]
As a [ ]
I want to [ ]
Scenario: [ ]
Given [ ]
When [ ]
Then [ ]

8. What is Gherkin?
The language I use for writing Cucumber features!

9. What is Cucumber?
• is a tool for running automated acceptance tests
written in a BDD style
• is written in the Ruby programming language
• projects are available for other platforms beyond
Ruby

10. Cucumber implementation
/features/adding.feature
Feature: Adding
Scenario: Add two numbers
Given the input "2+2“
When the calculator is run
Then the output should be "4"
/step_definitions/calculator_steps.rb
Given /^the input "([^"]*)"$/ do |input|
@input = input
end
When /^the calculator is run$/ do
@output = `ruby calc.rb #{@input}`
raise('Command failed!') unless $?.success?
end
Then /^the output should be "([^"]*)"$/ do |exp_out|
@output.should == exp_out
end

11. Cucumber testing stack

12. Capybara
• provides an API for accessing web pages and
interacting with them in a way that is very similar
to how a real user would
• allows you to plug in different web drivers
– including selenium
• it can use real browsers: Firefox, IE or Chrome,
or a number of different browser simulators

13. Capybara coding

14. Demo!!!
Create a project from scratch using the tech
stack from this presentation.

15. Why use Cucumber?
• It is relatively easy to set up.
• It supports multiple report formats, including HTML, JUNIT, PDF.
• It supports writing specifications in about 40 spoken languages
Test scenarios can be read by the stakeholders
• It allows scripting, abstraction and component reuse on several levels
• Although Cucumber is a Ruby tool, it can be used on other languages as .NET or JVM languages.
• It's integrated with all the most popular web testing libraries.
• It allows you to cross reference and index tests using tags, so that you can quickly find all tests
related to a function or run a group of related tests (e.g. quick tests, slow tests, integration tests,
accounting tests).
• It allows you to quickly write and execute a scenario using tabled data

16. Final Questions

17. Thank you!
Gabi Kis
Skype: gabikissv
Email: gabi.kis@evozon.com