Add Composer autoloading functions and PHPStan for testing

vendor/symfony/console/Tests/Fixtures/FoobarCommand.php

@@ -0,0 +1,25 @@
+<?php
+
+use Symfony\Component\Console\Command\Command;
+use Symfony\Component\Console\Input\InputInterface;
+use Symfony\Component\Console\Output\OutputInterface;
+
+class FoobarCommand extends Command
+{
+    public $input;
+    public $output;
+
+    protected function configure()
+    {
+        $this
+            ->setName('foobar:foo')
+            ->setDescription('The foobar:foo command')
+        ;
+    }
+
+    protected function execute(InputInterface $input, OutputInterface $output)
+    {
+        $this->input = $input;
+        $this->output = $output;
+    }
+}