public function setOptions(array $options) {
    foreach ($options as $key => $value) {
      if (is_int($key)) {
        $option  = '--' . $value;
      }
      elseif (strlen($key) == 1) {
        $option = '-' . $key;
        if (!empty($value)) {
          $option .= ' ' . escapeshellarg($value);
        }
      }
      else {
        // Do not render --uri=default.
        if ($key == 'uri' && $value == 'default') {
          continue;
        }
        $option = '--' . $key;
        if (!empty($value)) {
          $option .= '=' . escapeshellarg($value);
        }
      }
      if (!in_array($option, $this->options)) {
        $this->options[] = $option;
      }
    }
    return $this;
  }