The Gherkin crash course i made for my team mates.

1. GHERKIN
ubiquitous language for automated acceptance testing

2. What’s Gherkin?
• an ubiquitous language for
developers and stakeholders
• aimed for automated
acceptance tests
• it adheres to BDD

3. What’s BDD?
Behavior Driven Development
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4. Why Gherkin?
• write executable specifications
• enforce a collaborative approach
• force a specification format
• serve as living documentation

5. The language
• support for multiple languages
• small set of keywords:
Feature, Background, Scenario,
Given, When, Then, And, But, *,
Scenario Outline, Examples

6. Feature
• provide summary documentation
• one feature per file
• avoid long descriptions

7. Feature
Feature: feature title
In order to <meet some goal>
As a <type of stakeholder>
I want <a feature>

8. Scenario
• describes how system should
behave under a particular
situation
• follows a common pattern:
context, action, outcome

9. Scenario
Scenario: Successful withdrawal from an account
Given I have $100 in my account
When I request $20
Then my balance should be $80
context
outcome(s)
action(s)

10. Scenario
Scenario: Attempt withdrawal using blocked PIN
Given i have $100 in my account
But my PIN is blocked
When i withdraw $50
Then my request should be refuted
And i am forced to reset my PIN
context
outcome(s)
action(s)

11. Capturing values
• values passed to code as
arguments
• string wrapped by double quotes
• all of the numbers

12. Scenario: Request a new card
Given I’ve lost my “Visa”
When I request a new card at the “ACME” desk
And I specify a limit of $ 5000 bucks
Then I should be asked for my account details
And I should be provided with a brand new card
Capturing values

13. Scenario tips
• must make sense to the “others”
• must be executed independently
• must be deterministic

14. DRY strategies
• share common context
• avoid repeating scenarios
• group similar data
• strength focus on key examples

15. Scenario: Change PIN successfully
Given I have been issued a new card
And I insert the card, entering the correct PIN
When I choose “Change PIN” from the menu
And I change the PIN to 9876
Then the system should remember my PIN is now 9876
Scenario: Try to change PIN to the same as before
Given I have been issued a new card
And I insert the card, entering the correct PIN
When I choose "Change PIN” from the menu
And I try to change the PIN to the original number
Then I should see a warning message
Background

16. Background: Insert a newly issued card and sign in
Given I have been issued a new card
And I insert the card, entering the correct PIN
And I choose “Change PIN” from the menu
Scenario: Change PIN successfully
When I change the PIN to 9876
Then the system should remember my PIN is now 9876
Scenario: Try to change PIN to the same as before
When I try to change the PIN to the original number
Then I should see a warning message
Background

17. Background
• only one per feature file
• short is better
• avoid setting complicated state
• stick with givens

18. Given a User “Michael Jackson” born on “August 29, 1958”
And a User “Elvis” born on “January 8, 1935”
And a User “John Lennon” born on “October 9, 1940”
Data tables

19. Given these Users:
| name | date of birth |
| Michael Jackson | August 29, 1958 |
| Elvis | January 8, 1935 |
| John Lennon | October 9, 1940 |
Formatting
spaces are
ignored
Data tables

20. Scenario: Withdraw fixed amount of $50
Given i have $500 in my account
When i withdraw the fixed amount of $50
Then i should receive $50 cash
And the balance of my account should be $450
Scenario: Withdraw fixed amount of $100
Given i have $500 in my account
When i withdraw the fixed amount of $100
Then i should receive $100 cash
And the balance of my account should be $400
Scenario Outline

21. Scenario Outline: Withdraw fixed amount
Given i have <balance> in my account
When i withdraw the fixed amount of <withdrawal>
Then i should receive <received> cash
And the balance of my account should be <remaining>
Examples:
| balance | withdrawal | received | remaining |
| $500 | $50 | $50 | $450 |
| $500 | $100 | $100 | $400 |
As many cases
as you need
Scenario Outline

22. Scenario Outline: Withdraw fixed amount
Given i have <balance> in my account
When i withdraw the fixed amount of <withdrawal>
Then i should <outcome>
And the balance of my account should be <remaining>
Examples: Successful withdrawal
| balance | withdrawal | outcome | remaining |
| $500 | $50 | receive $50 cash | $450 |
Examples: Attempt to withdraw too much
| balance | withdrawal | outcome | remaining |
| $100 | $200 | see an error message | $100 |
Key examples

23. Best practices
• fix flickering scenarios
• guard from brittle features
• speed up slow features
• avoid bored stakeholders

24. Incidental details
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

25. Scenario: Check inbox
Given i have received an email from “Sue”
When i sign in
Then i should see 1 email from “Sue” in my inbox
Incidental details

26. Imperative VS declarative
Scenario: Redirect user to requested page after logging in
Given a User “dave” exists with password “secret”
And i am not logged in
When i navigate to the home page
Then i am redirected to the login form
When i fill in “Username” with “dave”
And i fill in “Password” with “secret”
And i press “Login”
Then i should be on the home page

27. Scenario: Redirect user to requested page after logging in
Given i am an unauthenticated User
When i attempt to view some restricted content
Then i am shown a login form
When i authenticate with valid credentials
Then i should be shown the restricted content
Imperative VS declarative

28. Who’s write Gherkin?
Tester
Developer
Product
Owner

29. ubiquitous language for automated acceptance testing
Questions?