Symfony 4 mock private services

Question

I have appplication which responsible to fetch various api's to collect data. I'm using Codeception As my testing framework and I need to mock API client class in my functional tests like this:

public function testFetchingNewApps(FunctionalTester $I) {
    $request = new Request(
        SymfonyRequest::METHOD_GET,
        'https://url.com/get'
    );

    $apiClientMock = \Mockery::mock(HttpClientInterface::class);
    $apiClientMock
        ->shouldReceive('send')
        ->with($request)
        ->andReturn(new Response(HttpCode::OK, [], '{"data":"some data"}'))
            ->once();

    $symfony = $this->getModule('Symfony')->grabService('kernel')->getContainer()->set(HttpClientInterface::class,   $apiClientMock);
    $symfony->persistService(HttpClientInterface::class, false);

    $I->runShellCommand('bin/console sync:apos --env=test');
}

But since Symfony 4 we can't get access to private services to mock them and I see the error like

service is private, you cannot replace it.

So I found that I can create ApiClinetMock.php whick extending real ApiCLient.php file and services_test.yml file. And in the services_test.yml I can make ApiClinetMock.php as a public service and associate it with the interface (overwrite interface usage):

#services_test.yml
services:
    _defaults:
        public: true
    Api\Tests\functional\Mock\ApiClientMock: ~
    ApiHttpClients\HttpClientInterface: '@Api\Tests\functional\Mock\ApiClientMock'

Now when I run my test case I do not see any error like

service is private, you cannot replace it.

but my mock is not working and returning real data instead of data I set in my mock and I do not know why.

The possible solution is to overwrite methods I need in ApiClientMock to return data what I need but it will work only for one test case but I need to test various different valid/invalid responses.

I know there is a lot of info about this issue in Symfony 4 but I still can't find any good example. Can someone explain to me how I should write functional tests and how to make proper mocks.

Updated I know I can use https://symfony.com/blog/new-in-symfony-4-1-simpler-service-testing but it's only working when you need to get private services but not working when you need to set/replace

Updated Also I tried to set Api\Tests\functional\Mock\ApiClientMock as synthetic but now I'm getting error:

The "Api\Tests\functional\Mock\ApiClientMock" service is synthetic, it needs to be set at boot time before it can be used.

Lei

Answer 1

Okay, I found why I still getting real data instead of mocked. The issue is that Codeception use CLI module (https://codeception.com/docs/modules/Cli) which is running new app, so data is not mocked there. To fix the issue I extend Symfony module to use Symfony CommandTester (https://symfony.com/doc/current/console.html#testing-commands) instead of Codeception CLI module.

For example I have HttpClientInterface:

<?php declare(strict_types = 1);

namespace App\Infrastructure\HttpClients;

use App\Infrastructure\HttpClients\Exceptions\HttpClientException;
use GuzzleHttp\Promise\PromiseInterface;
use Psr\Http\Message\RequestInterface;
use Psr\Http\Message\ResponseInterface;

/**
 * Interface HttpClientInterface
 * @package OfferManagement\Infrastructure\ApiOfferSync\HttpClients
 */
interface HttpClientInterface
{
    /**
     * Send an HTTP request.
     *
     * @param RequestInterface $request Request to send
     * @param array|array[]|string[]|integer[]  $options Request options to apply to the given
     *                                  request and to the transfer.
     *
     * @return ResponseInterface
     * @throws HttpClientException
     */
    public function send(RequestInterface $request, array $options = []): ResponseInterface;

    /**
     * Asynchronously send an HTTP request.
     *
     * @param RequestInterface $request Request to send
     * @param array|array[]|string[]|integer[]  $options Request options to apply to the given
     *                                  request and to the transfer.
     *
     * @return PromiseInterface
     */
    public function sendAsync(RequestInterface $request, array $options = []): PromiseInterface;
}

and his implementation GuzzleApiClient:

<?php declare(strict_types = 1);

namespace App\Infrastructure\HttpClients\Adapters\Guzzle;

use App\Infrastructure\HttpClients\Exceptions\HttpClientException;
use App\Infrastructure\HttpClients\HttpClientInterface;
use GuzzleHttp\Client;
use GuzzleHttp\Promise\PromiseInterface;
use Psr\Http\Message\RequestInterface;
use Psr\Http\Message\ResponseInterface;

class GuzzleApiClient implements HttpClientInterface
{
    /**
     * @var Client
     */
    private $apiClient;

    /**
     * GuzzleApiClient constructor.
     */
    public function __construct()
    {
        $this->apiClient = new Client();
    }

    /**
     * @param RequestInterface $request  Request to send
     * @param array|array[]|string[]|integer[] $options Request options to apply to the given
     *                                  request and to the transfer.
     *
     * @return ResponseInterface
     * @throws HttpClientException
     * @throws \GuzzleHttp\Exception\GuzzleException
     */
    public function send(RequestInterface $request, array $options = []):ResponseInterface
    {
        try {
            return $this->apiClient->send($request, $options);
        } catch (\Throwable $e) {
            throw new HttpClientException($e->getMessage());
        }
    }

    /**
     * Asynchronously send an HTTP request.
     *
     * @param RequestInterface $request Request to send
     * @param array|array[]|string[]|integer[] $options Request options to apply to the given
     *                                  request and to the transfer.
     *
     * @return PromiseInterface
     * @throws HttpClientException
     */
    public function sendAsync(RequestInterface $request, array $options = []):PromiseInterface
    {
        try {
            return $this->apiClient->sendAsync($request, $options);
        } catch (\Throwable $e) {
            throw new HttpClientException($e->getMessage());
        }
    }
}

in original service.yml all my services marked as private:

        services:
           _defaults:
                autowire: true
                autoconfigure: true
                public: false 
         
     
 App\Infrastructure\HttpClients\Adapters\Guzzle\GuzzleApiClient:
    shared: false

so I can't access them inside the tests to mock and I need to create service_test.yml and set there all services as public, and I need to create stub class which should implement HttpClientInterface but also ability to mock requests and associate it with HttpClientInterfacein the services_test.yml.

services_test.yml

services:
    _defaults:
        public: true

### to mock HttpClientInterface we need to override implementation for test env, note original implementation is not shared but here it should be shared
### as we need to always get same instance, but in the GuzzleApiClient we need add logic to clear data somehow after each test
    App\Tests\functional\Mock\GuzzleApiClient: ~
    App\Infrastructure\HttpClients\HttpClientInterface: '@App\Tests\functional\Mock\GuzzleApiClient'

App\Tests\functional\Mock\GuzzleApiClient:

<?php declare(strict_types=1);

namespace OfferManagement\Tests\functional\ApiOfferSync\Mock;

use App\Infrastructure\HttpClients
use App\Infrastructure\HttpClients\Adapters\Guzzle\Request;
use GuzzleHttp\Psr7\Response;
use App\Infrastructure\HttpClients\Exceptions\HttpClientException;
use Psr\Http\Message\RequestInterface;
use Psr\Http\Message\ResponseInterface;

/**
 * Class we using as a mock for HttpClientInterface. NOTE: this class is shared so we need clean up mechanism to remove
 * prepared data after usage to avoid unexpected situations
 * @package App\Tests\functional\Mock
 */
class GuzzleApiClient implements HttpClientInterface
{
    /**
     * @var array
     */
    private $responses;

    /**
     * @param RequestInterface $request
     * @param array $options
     * @return ResponseInterface
     * @throws HttpClientException
     * @throws \GuzzleHttp\Exception\GuzzleException
     */
    public function send(RequestInterface $request, array $options = []): ResponseInterface
    {
        $url = urldecode($request->getUri()->__toString());
        $url = md5($url);
        if(isset($this->responses[$url])) {
            $response = $this->responses[$url];
            unset($this->responses[$url]);

            return $response;
        }

        throw \Exception('No mocked response for such request')

    }


    /**
     * Url is to long to be array key, so I'm doing md5 to make it shorter
     * @param RequestInterface $request
     * @param Response $response
     */
    public function addResponse(RequestInterface $request, Response $response):void
    {
        $url = urldecode($request->getUri()->__toString());
        $url = md5($url);
        $this->responses[$url] = $response;
    }

}

At this point we have mechanism to mock requests doing it like:

$apiClient = $I->grabService(HttpCLientInterface::class);
$apiClient->addResponse($response);
$I->_getContainer()->set(HttpClientInterface::class, $apiClient)

but it will not work for CLI as we need to implement CommandTester as I mentioned at the beginning. To do so I need to extend Codeception Symfony module:

<?php declare(strict_types=1);

namespace App\Tests\Helper;


use Codeception\Exception\ModuleException;
use Codeception\TestInterface;
use Symfony\Bundle\FrameworkBundle\Console\Application;
use Symfony\Component\Console\Command\Command;
use Symfony\Component\Console\Tester\CommandTester;
use Symfony\Component\DependencyInjection\ContainerInterface;


class SymfonyExtended extends \Codeception\Module\Symfony
{
    private $commandOutput = '';

    public $output = '';

    public function _before(TestInterface $test)
    {
        parent::_before($test);
        $this->commandOutput = '';
    }

    public function _initialize()
    {
        parent::_initialize();
    }

    /**
     * @param string $commandName
     * @param array $arguments
     * @param array $options
     * @throws ModuleException
     */
    public function runCommand(string $commandName, array $arguments = [], array $options  = [])
    {
        $application = new Application($this->kernel);
        $command = $application->find($commandName);
        $commandTester = new CommandTester($command);

        $commandTester->execute(
            $this->buildCommandArgumentsArray($command, $arguments, $options)
        );

        $this->commandOutput = $commandTester->getDisplay();
        if ($commandTester->getStatusCode() !== 0 && $commandTester->getStatusCode() !== null) {
            \PHPUnit\Framework\Assert::fail("Result code was {$commandTester->getStatusCode()}.\n\n");
        }
    }

    /**
     * @param Command $command
     * @param array $arguments
     * @param array $options
     * @throws ModuleException
     * @return array
     */
    private function buildCommandArgumentsArray(Command $command, array $arguments, array $options):array
    {
        $argumentsArray['command'] = $command->getName();
        if(!empty($arguments)) {
            foreach ($arguments as $name => $value) {
                $this->validateArgument($name, $value);
                $argumentsArray[$name] = $value;
            }
        }

        if(!empty($options)) {
            foreach ($options as $name => $value) {
                $this->validateArgument($name, $value);
                $argumentsArray['--'.$name] = $value;
            }
        }

        return $argumentsArray;
    }

    /**
     * @param $key
     * @param $value
     * @throws ModuleException
     */
    private function validateArgument($key, $value)
    {

        if(
            !is_string($key)
            || empty($value)
        ) {
            throw new ModuleException('each argument provided to symfony command should be in format: "argument_name" => "value". Like: "username" => "Wouter"');
        }

        if($key === 'command') {
            throw new ModuleException('you cant add arguments or options with name "command" to symofny commands');
        }
    }

}

that's it! Now we can mock HttpCLientInterface and run $I->runCommand('app:command'):

$apiClient = $I->grabService(HttpCLientInterface::class);
$apiClient->addResponse($response);
$I->_getContainer()->set(HttpClientInterface::class, $apiClient);
$I->runCommand('app:command');

It's simplified version and I probably miss something, feel free to ask if you need some explanations!

Lei