Symfony\Component\DependencyInjection\ContainerBuilder::get PHP Method

    public function get($id, $invalidBehavior = ContainerInterface::EXCEPTION_ON_INVALID_REFERENCE)
    {
        $id = strtolower($id);

        if ($service = parent::get($id, ContainerInterface::NULL_ON_INVALID_REFERENCE)) {
            return $service;
        }

        if (!isset($this->definitions[$id]) && isset($this->aliasDefinitions[$id])) {
            return $this->get($this->aliasDefinitions[$id], $invalidBehavior);
        }

        try {
            $definition = $this->getDefinition($id);
        } catch (ServiceNotFoundException $e) {
            if (ContainerInterface::EXCEPTION_ON_INVALID_REFERENCE !== $invalidBehavior) {
                return;
            }

            throw $e;
        }

        $this->loading[$id] = true;

        try {
            $service = $this->createService($definition, $id);
        } finally {
            unset($this->loading[$id]);
        }

        return $service;
    }

 public function testProviderIsAdded()
 {
     $targetService = new Definition();
     $targetService->setClass('Faker\\Generator');
     $provider = $this->getMock('Acme\\Faker\\Provider\\CustomFakeDataProvider');
     $providerService = new Definition();
     $providerService->setClass(get_class($provider));
     $providerService->addTag('bazinga_faker.provider');
     $builder = new ContainerBuilder();
     $builder->addDefinitions(array('faker.generator' => $targetService, 'acme.faker.provider.custom' => $providerService));
     $builder->addCompilerPass(new AddProvidersPass());
     $builder->compile();
     $this->assertNotEmpty($builder->getServiceIds(), 'The services have been injected.');
     $this->assertNotEmpty($builder->get('faker.generator'), 'The faker.generator service has been injected.');
     $this->assertNotEmpty($builder->get('acme.faker.provider.custom'), 'The provider service has been injected.');
     /*
      * Schema:
      *
      * [0] The list of methods.
      *   [0] The name of the method to call.
      *   [1] The arguments to pass into the method call.
      *     [0] First argument to pass into the method call.
      *     ...
      */
     $targetMethodCalls = $builder->getDefinition('faker.generator')->getMethodCalls();
     $this->assertNotEmpty($targetMethodCalls, 'The faker.generator service got method calls added.');
     $this->assertEquals('addProvider', $targetMethodCalls[0][0], 'The faker.generator service got a provider added.');
     $this->assertEquals('acme.faker.provider.custom', $targetMethodCalls[0][1][0], 'The faker.generator service got the correct provider added.');
 }