phase-2.md

Phase 2: Use Dependency Injection to allow an Isolated Test

2.1: Move Mailer Dependency

By moving the creation of the Mailer object outside of the App class, we can now test the App class in isolation, with a Test Double.

index.php

<?php
require_once __DIR__ . '/vendor/autoload.php';

$to = '[email protected]';

$apiKey = 'C0wG3h1A5Fs5xNoLdM2S0w';
$mailer = new Mandrill($apiKey);

$app = new Src\App();
$app->setMailer($mailer);
$sent = $app->sendWelcomeEmail($to);

echo 'Welcome Email ' . ($sent ? 'Sent' : 'Failed') . '!';

src/App.php

Use a setter to inject the Mailer.

<?php
namespace Src;

require_once __DIR__ . '/../vendor/autoload.php';

Class App
{
    /** @var string $from */
    private $from = '[email protected]';
    /** @var string $subject */
    private $subject = 'Welcome to the App!';
    /** @var string $message */
    private $message = 'This is a welcome email!';

    /** @var Mandrill $mailer */
    private $mailer;

    /**
     * @param \Mandrill $mailer
     * @return $this
     */
    public function setMailer(\Mandrill $mailer)
    {
        $this->mailer = $mailer;
        return $this;
    }

    /**
     * @param $to
     * @return string
     */
    public function sendWelcomeEmail($to)
    {
        $email = [
            'to'         => [['email' => $to]],
            'from_email' => $this->from,
            'subject'    => $this->subject,
            'text'       => $this->message
        ];

        $this->mailer->messages->send($email);
        /**
         * Since Mandrill requires your sending domain to be verified even when using a test API key,
         * we will always get a failure, so we're going to skip checking the result of the send for this demo.
         */
        return true;
    }
}

tests/AppTest.php

Add an isolated test, using a test double, to test the sendWelcomeEmail() method in isolation. We can also test the Mailer injection using a test double.

<?php
namespace Tests;

require_once __DIR__ . '/../vendor/autoload.php';

use Src\App;

Class AppTest extends \PHPUnit_Framework_TestCase
{
    private $to = '[email protected]';

    public function testSetMailer()
    {
        $mailer = $this->getMockBuilder('Mandrill')
                       ->setConstructorArgs(['api-key'])
                       ->getMock();
        $app    = new App();
        $return = $app->setMailer($mailer);
        $this->assertEquals($return, $app);
    }

    public function testSendWelcomeEmail()
    {
        $mailer = $this->getMockBuilder('Mandrill')
                       ->setConstructorArgs(['api-key'])
                       ->getMock();
        $app    = new App();
        $app->setMailer($mailer);
        $result = $app->sendWelcomeEmail($this->to);
        $this->assertTrue($result);
    }

    /**
     * @group integrated
     */
    public function testSendWelcomeEmailIntegrated()
    {
        $apiKey = 'C0wG3h1A5Fs5xNoLdM2S0w';
        $mailer = new \Mandrill($apiKey);
        $app    = new App();
        $app->setMailer($mailer);
        $result = $app->sendWelcomeEmail($this->to);
        $this->assertTrue($result);
    }
}

phpunit: Passing

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