getText method
Get the generated texts, for testing purposes
Implementation
@visibleForTesting
String getText(String data) {
  final result = StringBuffer();
  for (final elem in makeText(data, 200, 200, 10, 5, 10)) {
    if (elem is BarcodeText) {
      result.write(elem.text);
    }
  }
  return result.toString();
}