gistfile1.php

<?php

// Problem:
// I'm testing a method which adds a service to a service container class which takes a service
// name and a callback which creates the service. Like so:

function load(ServiceContainer $container)
{
    $container->set(
        'event_dispatcher.listeners.db_extension',
        function ($sc) {
            return new SomeClass();
        }
    );
}


// Using PHPUnit I would do something along the lines of this

    public function testConfiguresServiceContainer()
    {
        $sc = new ServiceContainer();

        $this->objectBeingTested->load($sc);

        $this->assertInstanceOf(
            'SomeClass',
            $sc->get('event_dispatcher.listeners.db_extension')
        );
    }

// Using PHPSpec I came up with these 2 solutions

    public function it_should_attach_listener()
    {
        // Using a real service container, I would prefer this route
        // and it complies with "Don't mock what you don't own"
        $container = new ServiceContainer();
 
        $this->load($container);
 
        // Ugly hack: throw exception if "assert" fails
        if (!$container->get('event_dispatcher.listeners.db_extension') instanceof RepositoryListener) {
            throw new \Exception(
                'Service event_dispatcher.listeners.db_extension does not return '
                . ' TomPHP\PhpSpec\DbExtension\Listener\RepositoryListener'
            );
        }
    }
 
// This is probably a more elegant solution but I feel mocking the ServiceContainer is wrong
// as it's part of the framework rather than something in my module

    public function it_should_attach_listener_with_mock(ServiceContainer $container)
    {
        $container->setShared(
            'event_dispatcher.listeners.db_extension',
            Argument::that(function ($factory) {
                return $factory() instanceof RepositoryListener;
            })
        );
 
        $this->load($container);
    }

// One possible final solution might be that a "unit" shouldn't be doing such a thing and this
// code might be considered part of the configuration and therefore falls into integration testing

// Would love to hear some opinions!