Behaviour driven development

Aka BDD

What is BDD?

Get closer to the stakeholders

We all use different languages.

Make development more conversational

Make software that matters

It's not just a cool thing to have it really adds bussines value.

Evolution

• Unit tests: autotest your code.
• TDD: Test goes first.
• BDD: Design goes first.

Behat + Drupal

What is behat?

BDD framework written in PHP.

• Uses gherkin as a business readable and domain specific language
• Mink as a browser controller
• Free software
• Flexible (not only browsers)
• Constitutes a challenge

Gherkin syntax

Feature: Banana Calculator
In order to keep a stock of bananas
As Bob the Banana merchant,
I want a calculator that can add the amount of bananas so that I can know how many bananas I currently have

Scenario: Add 2 banana amounts
Given I have 3 Bananas
When I add 5 Bananas
Then I should have 8 Bananas


Drawbacks

• Slow.
• Understanding of the domain.
• Requires effort to make them robust.

Quickstart your install

composer require behat/behat

composer require drupal/drupal-extension='~3.1'
            

Initialize the skeleton

vendor/bin/behat --init
            

behat.yml

default:
  suites:
    default:
      contexts:
        - Drupal\DrupalExtension\Context\DrupalContext
  extensions:
    Behat\MinkExtension:
      goutte: ~
      base_url: http://example.org/  # Replace with your site's URL
    Drupal\DrupalExtension:
      blackbox: ~
            

Steps available

vendor/bin/behat -di
            

• Given I am logged in as a user with the :role role
• Given I am viewing a/an :type (content )with the title :title
• Then I should see the error message( containing) :message
• Then drush output should contain :output

Execute the tests

vendor/bin/behat
            

Speaking my language

Behat and gherkin

Translates each step in a PHP callback

Speaking my language

 use Drupal\DrupalExtension\Context\RawDrupalContext;
 use Behat\Behat\Context\SnippetAcceptingContext;
/**
 * Defines application features from the specific context.
 */
class FeatureContext extends RawDrupalContext implements SnippetAcceptingContext {
  private $bananas
  /**
   * @Given /^I have (\d+) bananas$/
   */
   public function iHaveBananas($b) {
     $this->bananas = $b;
   }
   ...
}
            

Speaking my language

  /**
   * @When /^I add (\d+) bananas$/
   */
   public function iAddBananas($b) {
     $this->bananas += $b;
   }
            

Speaking my language

  /**
   * @Then /^I should have (\d+) bananas$/
   */
   public function iShouldHaveBananas($b) {
     assertEquals($b, $this->bananas);
   }
            

Command a browser - Mink

Command a browser

            $session = $this->getSession();
            $session->visit('http://drupal.org');
            $session->getStatusCode();
            $session->getCurrentUrl();

            $page = $session->getPage();
            $e = $page->find('css', li:nth-child(4) a);
            $e->getText();
            $e->getAttribute('href');
            $e->click();

            

Awesome tricks

• Test in any browser.
• Debug tests
• Nice reports

Test with js enabled

• Goutte driver is only doing curl request
• Control when js is needed using @javascript tags in your scenarios
• Cookies and headers
• Manipulate the page
• Selenium, phantomjs

Test in any browser

• Different js implementations
• Screenshots

Anything is possible

 /**
   * @Given /^I switch to the first iframe$/
   */
  public function iSwitchToTheFirstIframe() {
    $javascript = <<<JS
(function(){
var iframes = document.getElementsByTagName('iframe');
var f = iframes[0];
f.id = "no_name_iframe";
})()
JS;
    $this->getSession()->executeScript($javascript);
    $this->getSession()->switchToIFrame('no_name_iframe');
  }
            

Debugging: Then I break.

Debugging - screenshot

HTML reports

Behat and drupal core.

It's so easy!

Very good documentation.