Class ServiceContainerTest boots up the kernel to test whether all service configurations are valid.

ServiceContainerTest.php

<?php
declare(strict_types=1);

namespace Tests\DI;

use Symfony\Bundle\FrameworkBundle\Test\KernelTestCase;

/**
 * Class ServiceContainerTest boots up the kernel to test whether all service configurations are valid.
 */
class ServiceContainerTest extends KernelTestCase
{
    /**
     * @test
     */
    public function buildContainer(): void
    {
        $kernel = static::bootKernel(['debug' => true]);
        self::assertTrue($kernel->isDebug());
    }
}