Testing constructor args in phpunit

Question

We use Varien_Http_Client to make http requests from a Magento extension, like this:

public function callApi(…)
{
    <SNIP>

    // Set default factory adapter to socket in case curl isn't installed.
    $client = new Varien_Http_Client($apiUri, array(
        'adapter' => 'Zend_Http_Client_Adapter_Socket',
        'timeout' => $timeout, 
    ));
    $client->setRawData($xmlDoc->saveXML())->setEncType('text/xml');
    $response = $client->request($method);
    $results = '';
    if ($response->isSuccessful()) {
        $results = $response->getBody();
    }
    return $results;
}

I understand I should avoid testing the internals of Varien_Http_Client; rather, I should test that we are sending it the right inputs, and handling its outputs correctly. I can mock Varien_Http_Client easily enough, but even if I refactor this code to let me replace the Varien_Http_Client with its mock, I don't understand how to generally* test that the constructor was called with the expected arguments, since the constructor is called by PHPUnit::getMock.

I don't need a mock object; I need a mock class. How can I test that a constructor was called with expected arguments?

* (In this case I know ways to work around this problem specific to Varien_Http_Client, but what can I do with more opaque third-party code?)

Answer 1

This is what we call "untestable" code. When you build dependencies inside your methods, there is no way to mock them. Every use of "new" keyword in your model is a signal that you should consider injecting the object instead of create it inside. In my opinion, the only exception from that rule is when you create a "data container" object or factory class. But in these cases probably you can test the object because methods will return it.

So as you said, the method you showed need a little refactor, for example:

class ApiClass
{
    protected $client;

    public function __construct(Varien_Http_Client $client)
    {
        $this->client = $client;
    }

    public function callApi()
    {
        $this->client->setRawData($xmlDoc->saveXML())->setEncType('text/xml');

        (...)

Best!