trivial test to ensure command does not crash

tests/Console/Command/ListFilesCommandTest.php

@@ -35,6 +35,7 @@ public function testListWithConfig()
         // make the test also work on windows
         $expectedPath = str_replace('/', \DIRECTORY_SEPARATOR, $expectedPath);
 
+        static::assertSame(0, $commandTester->getStatusCode());
         static::assertSame(escapeshellarg($expectedPath).PHP_EOL, $commandTester->getDisplay());
     }
 

tests/Console/Command/ListSetsCommandTest.php

@@ -0,0 +1,53 @@
+<?php
+
+/*
+ * This file is part of PHP CS Fixer.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *     Dariusz Rumiński <dariusz.ruminski@gmail.com>
+ *
+ * This source file is subject to the MIT license that is bundled
+ * with this source code in the file LICENSE.
+ */
+
+namespace PhpCsFixer\Tests\Console\Command;
+
+use PhpCsFixer\Console\Application;
+use PhpCsFixer\Console\Command\ListSetsCommand;
+use PhpCsFixer\Tests\TestCase;
+use PhpCsFixer\ToolInfo;
+use Symfony\Component\Console\Tester\CommandTester;
+
+/**
+ * @internal
+ *
+ * @covers \PhpCsFixer\Console\Command\ListSetsCommand
+ */
+final class ListSetsCommandTest extends TestCase
+{
+    public function testListWithConfig()
+    {
+        $commandTester = $this->doTestExecute([]);
+
+        $resultStart = ' 1) @DoctrineAnnotation
+      Rules covering Doctrine annotations';
+        static::assertStringStartsWith($resultStart, $commandTester->getDisplay());
+        static::assertSame(0, $commandTester->getStatusCode());
+    }
+
+    /**
+     * @return CommandTester
+     */
+    private function doTestExecute(array $arguments)
+    {
+        $application = new Application();
+        $application->add(new ListSetsCommand());
+
+        $command = $application->find('list-sets');
+        $commandTester = new CommandTester($command);
+
+        $commandTester->execute($arguments);
+
+        return $commandTester;
+    }
+}