CRUDlex\TwigExtensions::registerTwigExtensions PHP Method

    public function registerTwigExtensions(Container $app)
    {
        $self = $this;
        $app->extend('twig', function (\Twig_Environment $twig) use($self) {
            $twig->addFilter(new \Twig_SimpleFilter('arrayColumn', 'array_column'));
            $twig->addFilter(new \Twig_SimpleFilter('languageName', [$self, 'getLanguageName']));
            $twig->addFilter(new \Twig_SimpleFilter('float', [$self, 'formatFloat']));
            $twig->addFilter(new \Twig_SimpleFilter('basename', 'basename'));
            $twig->addFilter(new \Twig_SimpleFilter('formatDate', [$self, 'formatDate']));
            $twig->addFilter(new \Twig_SimpleFilter('formatDateTime', [$self, 'formatDateTime']));
            return $twig;
        });
    }

 protected function setUp()
 {
     $this->app = new Application();
     $this->app->register(new TwigServiceProvider());
     $twigExtensions = new TwigExtensions();
     $twigExtensions->registerTwigExtensions($this->app);
 }