[FIXED] CakePHP 3 - Mock HTTP\Client() in integration test

Issue

I am using Cake\Http\Client (book) to access some external applications. In my unit tests I cannot actually use those services.

So how to mock the Http Client in a controller integration test? It would be nice if I could for instance prescribe the exact response, without it ever making the actual HTTP request.

In my case the requests are made in a controller action and the destination is some other application on the same server. However, I feel like a solution to this should independent of the HTTP target.

Solution

I'm pretty certain there is no built-in solution to mocking the Http\Client object, considering I can't find anything in the docs or api pages.

So instead I used another PHP HTTP client, Guzzle. Guzzle does allow mocking by queuing pre-defined responses, exactly what I wanted.

However, smooth integration with CakePHP was not trivial since the Guzzle client constructor requires the mock stack to be passed. I solved this by creating a client factory:

<?php

namespace App\Guzzle;

use GuzzleHttp\Client;

/**
 * Guzzle factory
 * 
 * Created to make guzzle clients mockable
 */
class GuzzleFactory
{
    static $options = [];

    /**
     * Create new client
     * 
     * @return \GuzzleHttp\Client
     */
    static function create()
    {
        return new Client(self::$options);
    }

    /**
     * Set handler stack in global options for new clients
     * 
     * @param \GuzzleHttp\HandlerStack $handlerStack
     */
    static function setTest($handlerStack)
    {
        self::$options['handler'] = $handlerStack;
    }

    /**
     * Set options array to default
     */
    static function reset()
    {
        self::$options = [];
    }
}

Then in my controller tests I have the function:

/**
 * Set Guzzle mock responses
 * 
 * @param array $list
 */
public function setGuzzleResponses($list)
{
    if (!is_array($list))
    {
        $list = [$list];
    }
    $mock = new MockHandler($list);
    $handlerStack = HandlerStack::create($mock);
    GuzzleFactory::setTest($handlerStack);
}

Such that inside a test I can call:

    // ...
    $this->setGuzzleResponses([
        new Response(200, [], json_encode($response))
    ]);
    $this->get("/page/index"); // This request will make an HTTP call
    // ...

Also see http://docs.guzzlephp.org/en/stable/testing.html

Answered By - Roberto