PhpCsFixer\FixerFactory::registerBuiltInFixers PHP Method

    public function registerBuiltInFixers()
    {
        static $builtInFixers = null;
        if (null === $builtInFixers) {
            $builtInFixers = array();
            foreach (SymfonyFinder::create()->files()->in(__DIR__ . '/Fixer') as $file) {
                $relativeNamespace = $file->getRelativePath();
                $fixerClass = 'PhpCsFixer\\Fixer\\' . ($relativeNamespace ? $relativeNamespace . '\\' : '') . $file->getBasename('.php');
                if ('Fixer' === substr($fixerClass, -5)) {
                    $builtInFixers[] = $fixerClass;
                }
            }
        }
        foreach ($builtInFixers as $class) {
            $this->registerFixer(new $class(), false);
        }
        return $this;
    }

 /**
  * @dataProvider provideAllRulesFromSets
  */
 public function testIfAllRulesInSetsExists($rule)
 {
     $factory = new FixerFactory();
     $factory->registerBuiltInFixers();
     $fixers = array();
     foreach ($factory->getFixers() as $fixer) {
         $fixers[$fixer->getName()] = $fixer;
     }
     $this->assertArrayHasKey($rule, $fixers);
 }