This gist belongs to Clean Code Cookbook http://cleancodecookbook.com By Maximiliano Contieri http://maximilianocontieri.com

mockingAnExternalSystem.php

<?php

namespace phpUnitTutorial\Test;

use phpUnitTutorial\Payment;

class PaymentTest extends \PHPUnit_Framework_TestCase
{
    public function 
        testProcessPaymentReturnsTrueOnSuccessfulPayment()
    {
        $paymentDetails = array(
            'amount'   => 123.99,
            'card_num' => '4111-1111-1111-1111',
            'exp_date' => '03/2013',
        );

        $payment = new Payment();
        // Payment is a real one

        $response = new \stdClass();
        $response->approved = true;
        $response->transaction_id = 123;

        $authorizeNet = $this->getMockBuilder('\AuthorizeNetAIM')
            ->setConstructorArgs(
                array($payment::API_ID, $payment::TRANS_KEY))
            ->getMock();
        
        // External system is mocked

        $authorizeNet->expects($this->once())
            ->method('authorizeAndCapture')
            ->will($this->returnValue($response));

        $result = $payment->processPayment(
            $authorizeNet, $paymentDetails);

        $this->assertTrue($result);
    }
}