### Question:
FileUtils { public File download(String url) throws IOException { File file = new File(FileUtils.tempBaseDir(), SnowflakeId.defaultNextId() + Strings.DOT + FileUtils.extension(url)); download(url, file); return file; }  void mkdirs(File dir); void mkdirs(Path path); void mkdirs(String path); void mkdirs(String parent, String... children); void mkdirsForFile(File file); void touch(File file); void touch(Path path); void touch(String filepath); String extension(String filename); int countFiles(File file); int countFiles(File file, Predicate<File> filter); int countDirs(File file); int countDirs(File file, Predicate<File> filter); String absolutePath(File file); boolean isSamePath(File file, File another); boolean isRoot(File dir); int delete(File file); int deleteFile(File file); int deleteDir(File file); File tempDir(); File tempBaseDir(); int cleanTempBaseDir(); File createTempDir(String first, String... children); String parseMimeType(String filename); String getMimeType(String extension); File download(String url); void download(String url, File file);  }### Answer:
@Test public void testDownload() throws IOException { File file = new File("/tmp/baidu.png"); FileUtils.download("https: Assert.assertTrue(file.exists()); FileUtils.deleteFile(file); FileUtils.mkdirs(FileUtils.tempBaseDir()); file = FileUtils.download("https: FileUtils.deleteFile(file); }