HeaderTest.php

<?php
App::uses('CakeTestCase', 'TestSuite');
App::uses('HttpSocketResponse', 'Network/Http');

class HeaderTest extends CakeTestCase {

	public function testParseHeader() {
		$Response = new DebugHttpSocketResponse();
		$header_string = file_get_contents(__DIR__ . DIRECTORY_SEPARATOR . 'header.txt');
		$actual = $Response->_parseHeader($header_string);

		$this->assertEquals('Wed, 24 Feb 2016 06:35:43 GMT', $actual['Date']);
		$this->assertEquals('PHP/5.5.21', $actual['X-Powered-By']);
		$this->assertEquals(19, $actual['X-Total-Count']);
	}

}

class DebugHttpSocketResponse extends HttpSocketResponse {
	public function _parseHeader($header) {
		return parent::_parseHeader($header);
	}
}