phpunit mock method called in constructor - constructor

Question

I test a config class, which is parsing a config file and allows me to get the various settings for an app.
My goal is to mock the parse() method of the Config class, which is called in the constructor and to set what this method is returning in the constructor.
This way, it prevents file_get_contents() from being called (in the parse() method) and enables me to have a Config class with the config property already set to contain an array of properties.
But I haven't succeeded doing that.
Here is the code:
The config class:
<?php namespace Example;
use Symfony\Component\Yaml\Parser;
class Config
{
private $parser;
private $config;
public function __construct(Parser $parser, $filePath)
{
$this->parser = $parser;
$this->config = $this->parse($filePath);
}
public function parse($filePath)
{
$fileAsString = file_get_contents($filePath);
if (false === $fileAsString) {
throw new \Exception('Cannot get config file.');
}
return $this->parser->parse($fileAsString);
}
public function get($path = null)
{
if ($path) {
$config = $this->config;
$path = explode('/', $path);
foreach ($path as $bit) {
if (isset($config[$bit])) {
$config = $config[$bit];
}
}
return $config;
}
return false;
}
}
The test:
<?php namespace Example;
class ConfigTest extends \PHPUnit_Framework_TestCase
{
private function getConfigTestMock($configAsArray)
{
$parser = $this->getMockBuilder('\Symfony\Component\Yaml\Parser')
->getMock();
$configMock = $this->getMockBuilder('Example\Config')
->setConstructorArgs([$parser, $configAsArray])
->setMethods(['parse', 'get'])
->getMock();
$configMock->expects($this->once())
->method('parse')
->willReturn($configAsArray);
return $configMock;
}
/**
* #test
*/
public function get_returns_false_if_no_path_given()
{
$configMock = $this->getConfigTestMock(['param1' => 'value1']);
// Testing further...
}
}

Answer 1

I suggest you to make a functional test mocking the interaction with the file system, without do partial mocking of the tested class.
I recently discover the vfsStream library used in a great article of William Durand about Symfony2 and DDD.
So you can install this library in your composer.json (I tested the solution with the 1.4 version) and try this example test class:
<?php
namespace Acme\DemoBundle\Tests;
use Acme\DemoBundle\Example\Config;
use org\bovigo\vfs\vfsStream;
use Symfony\Component\Yaml\Parser;
class ConfigTest extends \PHPUnit_Framework_TestCase
{
/**
* #test
*/
public function valid_content()
{
$content = "param1: value1";
$root = vfsStream::setup();
$file = vfsStream::newFile('example.txt')
->withContent($content)
->at($root);
$filepath = $file->url();
$parser = new Parser();
$config = new Config($parser, $filepath);
$this->assertEquals("value1", $config->get("param1"));
}
}
Hope this help

Answer 2

For test the Config class you need to mock only the Parser and use the real Config class. As Example:
<?php
namespace Acme\DemoBundle\Tests;
use Acme\DemoBundle\Example\Config;
class ConfigTest extends \PHPUnit_Framework_TestCase
{
private function getConfigTestMock($configAsArray)
{
$parser = $this->getMockBuilder('\Symfony\Component\Yaml\Parser')
->getMock();
$parser->expects($this->once())
->method('parse')
->willReturn($configAsArray);
$configMock = new Config($parser,"fakePath");
return $configMock;
}
/**
* #test
*/
public function get_returns_false_if_no_path_given()
{
$configMock = $this->getConfigTestMock(['param1' => 'value1']);
$this->assertEquals("value1",$configMock->get("param1"));
// Testing further...
}
}
Hope this help