Test applications services can boot

ContainerTest.php

<?php

namespace Tests\Integration;

use Symfony\Bundle\FrameworkBundle\Test\KernelTestCase;
use Symfony\Component\Config\FileLocator;
use Symfony\Component\DependencyInjection\ContainerBuilder;
use Symfony\Component\DependencyInjection\Definition;
use Symfony\Component\DependencyInjection\Loader\XmlFileLoader;

class ContainerTest extends KernelTestCase
{
    private const FILTER_LIST = [
        // some services can exist only in dev or prod (thus not in test env)
        // or some services are behind some features flags
        // or some services are static (thus they are not real service)
    ];

    public function testContainer()
    {
        static::bootKernel(['debug' => true]);
        $projectDir = static::getContainer()->getParameter('kernel.project_dir');
        $container = static::getContainer();

        $builder = new ContainerBuilder();
        $loader = new XmlFileLoader($builder, new FileLocator());
        $loader->load($container->getParameter('debug.container.dump'));

        $count = 0;

        foreach ($builder->getDefinitions() as $id => $service) {
            if ($this->isSkipped($id, $service, $builder, $projectDir)) {
                continue;
            }

            $container->get($id);
            ++$count;
        }

        $this->addToAssertionCount($count);
    }

    private function isSkipped(string $id, Definition $service, ContainerBuilder $builder, string $projectDir): bool
    {
        if (str_starts_with($id, '.instanceof.') || str_starts_with($id, '.abstract.') || str_starts_with($id, '.errored.')) {
            return true; // Symfony internal stuff
        }

        if ($service->isAbstract()) {
            return true; // Symfony internal stuff
        }

        $class = $service->getClass();
        if (!$class) {
            return true; // kernel, or alias, or abstract
        }

        if (\in_array($class, self::FILTER_LIST)) {
            return true;
        }

        $rc = $builder->getReflectionClass($class, false);
        if (!$rc) {
            return true;
        }

        $filename = $rc->getFileName();
        if (!str_starts_with($filename, "{$projectDir}/src")) {
            return true; // service class not in tests/Integration
        }

        if ($rc->isAbstract()) {
            return true;
        }

        return false;
    }
}

Another optimization that can be made: report all failures, instead of only the first one.

@lyrixx closing } for the test class is missing in the gist 😊.

FYI, I ended up with something like this as a PoC:

class ContainerTest extends KernelTestCase
{
    private const FILTER_LIST = [
        // some services can exist only in dev or prod (thus not in test env)
        // or some services are behind some features flags
        // or some services are static (thus they are not real service)
    ];

    public function testContainer(): void
    {
        static::bootKernel(['debug' => true]);
        $projectDir = static::getContainer()->getParameter('kernel.project_dir');
        $container = static::getContainer();

        $this->bootstrapContainer($container);

        $builder = new ContainerBuilder();
        $loader = new XmlFileLoader($builder, new FileLocator());
        $loader->load($container->getParameter('debug.container.dump'));

        $invalidServices = [];
        $count = 0;

        foreach ($builder->getDefinitions() as $id => $service) {
            if ($this->isSkipped($id, $service, $builder, $projectDir)) {
                continue;
            }

            try {
                $container->get($id);
            } catch (\Throwable $e) {
                $invalidServices[] = sprintf('[%s] %s', $id, $e->getMessage());
                continue;
            }

            ++$count;
        }

        $this->addToAssertionCount($count);

        if (count($invalidServices) > 0) {
            throw new \RuntimeException(sprintf(
                "Invalid services found: \n  - %s",
                implode("\n\n  - ", $invalidServices)
            ));
        }
    }

    private function isSkipped(string $id, Definition $service, ContainerBuilder $builder, string $projectDir): bool
    {
        if (str_starts_with($id, '.instanceof.')
            || str_starts_with($id, '.abstract.')
            || str_starts_with($id, '.errored.')
            || $service->isAbstract() // Incomplete definitions that can't be instantiated
            || $service->isSynthetic() // Synthetic services don't actually have a definition, these are set in runtime
            || $service->isLazy() // @TODO support lazy services
        ) {
            return true; // Symfony internal stuff
        }

        $class = $service->getClass();
        if (!$class) {
            return true; // kernel, or alias, or abstract
        }

        if (\in_array($class, self::FILTER_LIST)) {
            return true;
        }

        $rc = $builder->getReflectionClass($class, false);
        if (!$rc) {
            return true;
        }

        $filename = $rc->getFileName();
        if (false === $filename || str_starts_with($filename, "{$projectDir}/vendor/symfony")) {
            return true;
        }

        if ($rc->isAbstract()) {
            return true;
        }

        return false;
    }

    /**
     * Do all the stuff required for bootstrapping services/factories, that are used when services are being built
     */
    private function bootstrapContainer(ContainerInterface $container): void {
    }
}

The differences from gist's version:

• iterate over all service, collect all the errors and print them at once at the end
• ignore synthetic services (these are meant to be set in runtime, no need to check them)
• ignore lazy services (it's something to tackle, I had some problems and did not want to spend much time on it)
• ignore Symfony services registered from vendor/symfony, instead of narrowing to src only (our app has several dirs with production code, I did not want to list them all or to prepare complex logic)
• skip if service reflection returned false

Anyway, thanks for sharing, it was good to make some kind of experiment. What I found more than lint:container is that we rely on EventDispatcher, not on EventDispatcherInterface, so when traceable event dispatcher is injected in test environment, there's TypeError, which menas we should fix the signatures and use the interface as a contract.

PS. in our case bootstrapContainer() has logic, I just removed it as it's crafted for our code. But it there are any things that need to be pre-defined before services are created (like $_SERVER['HTTP_CLIENT_IP'] for example), you also need to do it before iterating over container.