Fixed support for Kernel as command

Author: yceruto

Tests/Kernel/KernelCommand.php

@@ -0,0 +1,26 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <[email protected]>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Bundle\FrameworkBundle\Tests\Kernel;
+
+use Symfony\Component\Console\Attribute\AsCommand;
+use Symfony\Component\Console\Output\OutputInterface;
+
+#[AsCommand(name: 'kernel:hello')]
+final class KernelCommand extends MinimalKernel
+{
+    public function __invoke(OutputInterface $output): int
+    {
+        $output->write('Hello Kernel!');
+
+        return 0;
+    }
+}

Tests/Kernel/MicroKernelTraitTest.php

@@ -13,7 +13,11 @@
 
 use PHPUnit\Framework\TestCase;
 use Psr\Log\NullLogger;
+use Symfony\Bundle\FrameworkBundle\Console\Application;
 use Symfony\Bundle\FrameworkBundle\Kernel\MicroKernelTrait;
+use Symfony\Component\Console\Attribute\AsCommand;
+use Symfony\Component\Console\Input\ArrayInput;
+use Symfony\Component\Console\Output\BufferedOutput;
 use Symfony\Component\DependencyInjection\ContainerBuilder;
 use Symfony\Component\DependencyInjection\Extension\ExtensionInterface;
 use Symfony\Component\DependencyInjection\Loader\ClosureLoader;
@@ -152,6 +156,23 @@ public function testSimpleKernel()
         $this->assertSame('Hello World!', $response->getContent());
     }
 
+    public function testKernelCommand()
+    {
+        if (!property_exists(AsCommand::class, 'help')) {
+            $this->markTestSkipped('Invokable command no available.');
+        }
+
+        $kernel = $this->kernel = new KernelCommand('kernel_command');
+        $application = new Application($kernel);
+
+        $input = new ArrayInput(['command' => 'kernel:hello']);
+        $output = new BufferedOutput();
+
+        $this->assertTrue($application->has('kernel:hello'));
+        $this->assertSame(0, $application->doRun($input, $output));
+        $this->assertSame('Hello Kernel!', $output->fetch());
+    }
+
     public function testDefaultKernel()
     {
         $kernel = $this->kernel = new DefaultKernel('test', false);