CucumberSam Davarnia

@samdvr samdvr.com

About

Sr.Web Developer working mostly with Ruby on Rails.

Interests: Databases, Object Oriented Design, Testing, Concurrency and Scalability.

@samdvr

samdvr.com

I. Test  Driven  Development  II.Behavior  Driven  Development  III.Cucumber

Why write tests?More Confidence

Feedback

Reduce Bugs

Better Software Design

Refactoring

Unit Test

Unit  Under  Test

Mock

Mock

Integration Test

Unit  Tests

Integration

Test Driven Development

Kent Beck

Test First Development

TDD Cycle

WRITE A FAILING TEST

MAKE THE TEST PASS

REFACTOR

Red

Write a failing test

Reasoning

Verify that our test is validating what we want

Green

Write the simplest implementation that makes the test pass

Refactor

Improve the internal structure of code.

Myths about TDD

TDD is time consuming

Code is hard to test

Tests are slow

Myths about TDD

TDD is

time consuming

Myths about TDDCode is hard to test

Bad/No software Design

Too many dependencies

Queries combined with Commands

Violating The Law of Demeter

and …

Myths about TDD

Tests are slow

Lack of isolation

Test Brittleness

Behavior Driven Development

• Focus on specifications • Unified vocabulary • Outside In • User Centric • Good TDD practitioners are BDD

practitioners

What’s CucumberBDD Framework for integration tests

Easy to read syntax

Bridge the gap between stakeholder and developer

It can use a web driver or be isolated

It can test ruby, .Net, PHP and Java

Starting CucumberAfter  Installing  the  cucumber  gem,  We  make  a  directory  called  features  Each  scenario  is  in  this  directory  with  .feature  extension.  

..  features/books.feature  ..

Gherkin Syntax

Feature:  <General  purpose  of  a  feature>      Scenario:  <Scenario  in  the  feature>          Given  <Context>          When  <Action>  

Then  <Expectation>          

Gherkin Syntax

Feature:  Manage  Books      Scenario:  Admin  User  can  create  books          Given  I  am  an  admin  user          When  I  create  a  book  ‘1984’  

And    visit  the  homepage  Then  I  should  see  ‘1984’    

     

Running CucumberYou  can  implement  step  definitions  for  undefined  steps  with  these  snippets:  

Given(/^I  am  an  admin  user$/)  do      pending  #  express  the  regexp  above  with  the  code  you  wish  you  had  end  

When(/^I  create  a  book  “(\d+)”$/)  do  |arg1|      pending  #  express  the  regexp  above  with  the  code  you  wish  you  had  end  

When(/^visit  the  homepage$/)  do      pending  #  express  the  regexp  above  with  the  code  you  wish  you  had  end  

Then(/^I  should  see  “(\d+)”$/)  do  |arg1|      pending  #  express  the  regexp  above  with  the  code  you  wish  you  had  end

Run:  cucumber  in  your  app  directory    

Step Definitions

Step  definitions  are  regular  expressions  that  help  cucumber  understand  Gherkin.

We  store  step  definitions  in    features/step_definitions/book_step.rb

Step DefinitionsGiven(/^I  am  an  admin  user$/)  do      pending  #  express  the  regexp  above  with  the  code  you  wish  you  had  end  

When(/^I  create  a  book  “(\d+)”$/)  do  |book_name|      pending  #  express  the  regexp  above  with  the  code  you  wish  you  had  end  

When(/^visit  the  homepage$/)  do      pending  #  express  the  regexp  above  with  the  code  you  wish  you  had  end  

Then(/^I  should  see  “(\d+)”$/)  do  |expected_output|      pending  #  express  the  regexp  above  with  the  code  you  wish  you  had  end

Making it all GreenGiven(/^I  am  an  admin  user$/)  do    current_user.role  ==  ‘admin’  

end  

When(/^I  create  a  book  “(\d+)”$/)  do  |book_name|      Book.create(name:  book_name)  end  

When(/^visit  the  homepage$/)  do      visit  root_path  end  

Then(/^I  should  see  “(\d+)”$/)  do  |expected_output|      expect(page).to  have_content  expected_output    end

Implementation

Running  cucumber  again  will  show  RED  for  each  step.  

We  write  implementation  necessary  to  make  each  step  GREEN  

Scenario OutlinesScenario  Outline:  eating      Given  there  are  <start>  cucumbers      When  I  eat  <eat>  cucumbers      Then  I  should  have  <left>  cucumbers  

   Examples:          |  start  |  eat  |  left  |          |    12      |    5    |    7      |          |    20      |    20  |    0      |

Data Tables

Given  the  following  users  exist:      |  name    |  email                      |  phone  |      |  Aslak  |  aslak@email.com  |  123      |      |  Matt    |  matt@email.com    |  234      |      |  Joe      |  joe@email.org      |  456      |

Tags

cucumber  -­‐-­‐tags  @important      

   @important      Scenario:  Missing  product  description      ...        Scenario:  Several  products      ...

Cucumber Anti-PatternsFeature:  Manage  Books      Scenario:  Admin  User  can  create  books          Given  I  visit  the  homepage  

And      fill_in  username  with  ‘Sam’  And  fill_in  password  with  ‘something’  And  click  ‘login’    

       When  I  create  a  book  with  name  ‘1984’  And    visit  the  homepage  Then  I  should  see  ‘1984’  in  the  name  column    

     

Cucumber Anti-patterns

Tightly coupled to implementation

Test overlap

Too much knowledge per step

Developer centric

Cucumber Patterns

Test the Interface not the implementation

Test the boundaries of the system

Focus on the messages between the objects

Resources

Questions?@samdvr  samdvr.com