Behat - The Right Way
Behat is a wonderful tool for automatic testing. It allows you to write your user stories and scenarios in proper English, which is then parsed by Behat and transformed to a set of clicks or other operations that mimic a real user.
If you don’t have automated tests on your project, I would argue that you’re doing it wrong (I explain why on The Gizra Way presentation). Even having a single test is much better than none.
With that said, it’s super easy to abuse Behat. We are developers and we think sort of like machines (not really, but you get my point). If you would like to test login to your site you could easily do
Given I visit "/user/login"
# fill the username and password input fields, and click submit
When I fill "username" with "foo"
And I fill "password" with "bar"
And I press "Login"
Then I should get a "200" HTTP response
Your test will return green, but it could be improved:
Given I login with an "authenticated" user
When I go to the homepage
Then I should have access
As you see we are avoiding writing scripted tests, and try to describe what should happen – not the clicks that got us there.
Meta steps are a great way to help you write your step definition (i.e. each line that is translated to code) with reusable code. So for example
Given a group "Public Group 1" with "Public" access is created with group manager "group1-admin"
Would be defined as:
<?php
/**
* @Given /^a group "([^"]*)" with "([^"]*)" access is created with group manager "([^"]*)"$/
*/
public function aGroupWithAccessIsCreatedWithGroupManager($title, $access, $username) {
$steps = array();
// Login with existing users.
$steps[] = new Step\When('I am logged in as user "'. $username .'"');
$steps[] = new Step\When('I visit "node/add/group"');
// Set the title and body fields.
$steps[] = new Step\When('I fill in "title" with "' . $title . '"');
$steps[] = new Step\When('I fill in "edit-body-und-0-summary" with "Some text"');
// ... Do any logic needed.
return $steps;
}
Also, we avoid hardcoding any URL, so instead of writing When I visit node/1
we could write When I visit "Public Group 1" of type "group" and write some
code to find the node by the title and redirect us there.
<?php
/**
* @When /^I visit "([^"]*)" node of type "([^"]*)"$/
*/
public function iVisitNodePageOfType($title, $type) {
$query = new entityFieldQuery();
$result = $query
->entityCondition('entity_type', 'node')
->entityCondition('bundle', strtolower($type))
->propertyCondition('title', $title)
->propertyCondition('status', NODE_PUBLISHED)
->range(0, 1)
->execute();
if (empty($result['node'])) {
$params = array(
'@title' => $title,
'@type' => $type,
);
throw new Exception(format_string("Node @title of @type not found.", $params));
}
$nid = key($result['node']);
// Use Drupal Context 'I am at'.
return new Given("I go to \"node/$nid\"");
}
Behat allows you to create a clean interface to your system, without having your internal implementation leak out. Just like RESTful is doing, but for testing instead of REST API.
Headless Drupal
As we are working on decoupled backend and frontend, we still want to have our code properly tested.
A nice technique we’ve been using is installing the backend (Drupal) and frontend (AngularJS webapp) on the same Travis instance and running Behat tests on the frontend. By having the backend present we don’t need to mock any data just for the frontend, as we already have some dummy migrated data as part of every installation profile. For that we use PhantomsJS (easy install).
For the brave, see our .travis configuration that runs both API and Javascript tests on our fully decoupled app. Note that the linked project is nowhere near ready, but it can still be valuable if you want to see how we got Travis to run our tests.
CasperJS Vs Behat
@juampy from Lullabot has recommended in his blog post to use CasperJs to test JS. I believe Behat could be better simply because it’s easier to read. For example take this CasperJs code:
casper.test.begin('Tests homepage structure', 7, function suite(test) {
casper.start('http://www.msnbc.com', function() {
// Verify that the main menu links are present.
test.assertExists('a.j-signin-label', '"Sign in" link is found.');
test.assertExists('a.j-register-label', '"Sign up" link is found.');
test.assertExists('li.main-nav__link--explore a', '"Explore" link is found.');
test.assertExists('li.main-nav__link--watch a', '"Watch" link is found.');
test.assertExists('li.main-nav__link--join-in a', '"Join In" link is found.');
test.assertExists('li.main-nav__link--speak-out a', '"Speak Out" link is found.');
// 10 articles should be listed.
test.assertElementCount('article', 10, '10 articles are listed.');
});
casper.run(function() {
test.done();
});
});
… and imagine how it could have been translated to Behat:
@javascript
Scenario: Validate an anonymous user can see all links, and a list of articles.
Given I am an anonymous user
When I visit the homepage
Then I should see the main menu links for "anonymous" user are present
And I should see a teaser with "10" items of recent articles
The underlying code in the end will be very close to the one in CasperJS - however it better defined what is needed, not only how it should appear, and arguably it’s more readable by other developers.
Amitai Burstein
@amitaibu
