static public boolean createMissingParentDirectories(File file) {
        File parent = file.getParentFile();
        if (parent == null) {
            // Parent directory not specified, therefore it's a request to
            // create nothing. Done! ;)
            return true;
        }

        // File.mkdirs() creates the parent directories only if they don't
        // already exist; and it's okay if they do.
        parent.mkdirs();
        return parent.exists();
    }
@Test
    public void createParentDirIgnoresExistingDir() {
        String target = CoreTestConstants.OUTPUT_DIR_PREFIX + "/fu" + diff + "/testing.txt";
        File file = new File(target);
        cleanupList.add(file);
        file.mkdirs();
        assertTrue(file.getParentFile().exists());
        assertTrue(FileUtil.createMissingParentDirectories(file));
    }