Webmozart\Console\Api\Config\Config::getHandler PHP Method

    public function getHandler()
    {
        if (!$this->handler) {
            return $this->getDefaultHandler();
        }
        if (is_callable($this->handler)) {
            $this->handler = call_user_func($this->handler);
        }
        return $this->handler;
    }

 public function testDefaultHandler()
 {
     $this->assertEquals(new NullHandler(), $this->config->getHandler());
 }