<?php class Sample { public function error() { $this->redirect(); } public function redirect() { header("Location: http://github.com/"); } } <?php require_once 'Sample.php'; class SampleTest extends PHPUnit_Framework_TestCase { public function testCallRedirectWhenError() { $sample = $this->getMockBuilder('Sample') ->setMethods(array('redirect')) ->getMock(); $sample->expects($this->once())->method