User Acceptance Testing with Behat, Mink and PhantomJS

User Acceptance Testing with Behat, Mink, and

PhantomJSChattanooga PHP Developers Group

December 3, 2014

User Acceptance Testing?

• Rooted in agile software development

• Used to verify that a solution “works” for the user

• Ideally created by business customers

• Expressed in a business domain language

Business Domain Language?

• Written in the “business speak” of the client’s business world, or “domain”

• Geared toward “business readable”

• Designed to bridge the communications gap between product owners (clients) and developers (us) by expressing requirements in a common language that both sides understand

Why is this important?

What’s the benefit?

• Increases customer / developer mutual understanding of objectives

• Increases odds of the application you develop actually meeting the customer expectations

• Increases customer satisfaction

Crafting Good Acceptance Tests

• Starts with a User Story

• A User Story is the smallest piece of functionality that adds business value

• A Good User Story is a Feature Set of your project

Structure of a User Story

• As a user who…(target user role)

• I need…(business need)

• In order to….(benefit)

Good User Stories are written by the customer

User Story Example

• As a student…

• I want to purchase a parking pass...

• So I can park on campus without getting a ticket or being towed

User Stories are Prioritized

• By the client

• Based on business importance

• With feedback from the development team

• Highest agreed priority items get worked on first

Next Come Acceptance Criteria

• Written before programming begins

• Defines the specific functional aspects of the user story

• Feature set is complete when all Acceptance Criteria are met (i.e, all Acceptance tests for that Feature are passed)

Structure of Acceptance Criteria

• Given that I am (user precondition)

• When I do this (performs action)

• Then I should (see observable results)

This is called a “Scenario”

and each of the above is a “step”

Feature

• A “Feature” is comprised of a User Story and it’s supporting Acceptance Criteria

As a PHP Developer, how do I get there?

...You start with Behat

What is Behat?

• A testing framework written in PHP

• Accepts tests written in a business domain language

• Executes those test on your application

• Designed to test the behavior of your application

Behat works with Mink

• Mink is an open source browser controller/emulator for web applications

• Written in PHP

• Integrates with Behat via the Mink Extension

What does the Mink Extension Provide?

• Predefined “steps” that comprise the components of Acceptance Tests

• Each “step” maps to a PHP callback that contains the code for the test

But, wait, you said...

• Tests were written in “business speak”

!

• And they are….using a structured, highly readable language called Gherkin

Gherkin

• Gherkin is a business readable, domain specific language created specifically for crafting behavior descriptions

• These behavior descriptions serve as both your product documentation and your acceptance tests

Behat does the work

• Features (User Stories and Acceptance Tests) are written in Gherkin and are composed of steps

• Steps are parsed by Behat using regular expressions, and mapped to PHP Callbacks

• PHP Callbacks execute test code that powers Mink

• Mink runs browser simulations to test applications

PhantomJS

• Headless WebKit scriptable with a JavaScript API

• Native support for DOM Handling, CSS selectors, JSON, Canvas, SVG and more

• Gets triggered in your Acceptance tests by specifying the “@javascript” tag on your test — replaces cURL calls with actual WebKit function executions

• Behat is Pluggable, through extensions

• Mink Extension is a Behat Plugin

• Extensions exist for various frameworks including:

• Drupal

• Symfony/Symfony2

• Yii

Let’s Play

!

!

{! "require": {! "behat/behat": "2.4.*@stable",! "behat/mink": "1.5.*@stable",! "behat/mink-extension": "*",! "behat/mink-goutte-driver": "*",! "behat/mink-selenium2-driver": "*",! "behat/yii-extension": "*",! ! "drupal/drupal-extension": "*"! },! "minimum-stability": "dev",! "config": {! "bin-dir": "bin/"! }!}

composer.json

$> composer install

You’ll get

• bin/ -- contains Behat executable

• vendor/ -- contains dependencies, including Mink Extension, Drupal Extension, Yii extension and their dependencies

Next you need to define your test environment parameters

behat.ymldefault:! extensions:! Behat\MinkExtension\Extension:! goutte: ~! selenium2:! wd_host: "http://localhost:8643/wd/hub"! base_url: "http://www.supplyhog.com"! Drupal\DrupalExtension\Extension:! blackbox: ~! region_map:! content: "#content"!

Now you need to initialize your test environment

$> bin/behat --init

Now you also get...• features/ -- Directory that will house your

features (user stories and scenarios) written in Gherkin

• features/bootstrap/FeatureContext.php -- Context extension that will house any of your application specific test callbacks

• Will extend DrupalExtension Context (the Drupal Extension provides the ability to designate a “region” based on a CSS selector)

FeatureContext.php

• Change Class Extension from:

class FeatureContext extends BehatContext

• to

class FeatureContext extends Drupal\ DrupalExtension\Context\DrupalContext

Predefined Steps

$bin/behat -di !

or !

$bin/behat -dl

Write your Feature

• Saved in the features/ directory in a file called <something>.feature

• Can have multiple .feature files in this directory

• All will get executed unless otherwise specified