public static void main(String[] args) throws IOException {

    // create the file writer and execute the custom action
    FileWriterAction writeHello = writer -> writer.write("Gandalf was here");
    new SimpleFileWriter("testfile.txt", writeHello);

    // print the file contents
    try (var scanner = new Scanner(new File("testfile.txt"))) {
      while (scanner.hasNextLine()) {
        LOGGER.info(scanner.nextLine());
      }
    }
  }
@Test
  void shouldExecuteApplicationWithoutException() {
    assertDoesNotThrow(() -> App.main(new String[]{}));
  }