### Question:
FileService { @Transactional public List listAllFiles(){ return fileDao.listAllFiles(); }  @Autowired void setFileDao(FileDao fileDao); boolean insert(File file); @Transactional List listAllFiles(); @Transactional boolean deleteFile(int id);  }### Answer:
@Test public void testListAllFiles()throws Exception{ List files = fileService.listAllFiles(); File file = (File)files.get(0); assertEquals(files.isEmpty(), false); }