### Question:
FileUtilities { public static String getSuffix(File file) { return getSuffix(file.getName()); } private  FileUtilities(); static boolean archive(Path file); static boolean copyDirectory(File source, File destination, boolean copySubDirectories); static boolean copyfile(File srFile, File dtFile); static boolean createDirectories(File dir); static boolean createDirectoriesAndFile(File file); static boolean deleteDirRecursive(File fileOrDir); static File ensureSuffix(File file, String suffix); static List<String> explodeZip(InputStream inStream, File outputLocation, long seed); static String getBasename(File file); static String getDirectory(File baseDirectory, long seed); static long getDirSize(File file); static List<File> getFilesFromDirectory(File directory, final String extension); static String getSuffix(File file); static String getSuffix(String file); static ByteBuffer readFileToBuffer(File in); static List<String> readLines(File file);  }### Answer:
@Test public void testGetSuffixFile() { Assert.assertNull(FileUtilities.getSuffix(new File(XYZ))); Assert.assertNull(FileUtilities.getSuffix(new File("." + XYZ))); Assert.assertEquals(XYZ, FileUtilities.getSuffix(new File("a." + XYZ))); Assert.assertEquals(XYZ, FileUtilities.getSuffix(new File("C:\\path.dir\\last." + XYZ))); }
@Test public void testGetSuffixString() { Assert.assertNull(FileUtilities.getSuffix(XYZ)); Assert.assertNull(FileUtilities.getSuffix("." + XYZ)); Assert.assertEquals(XYZ, FileUtilities.getSuffix("a." + XYZ)); Assert.assertEquals(XYZ, FileUtilities.getSuffix("C:\\path.dir\\last." + XYZ)); }