    @Test
    @SuppressWarnings({"unused", "UnusedAssignment"})

    public void copy() throws IOException {
        File a = File.createTempFile("file-1", "tmp");
        File b = File.createTempFile("file-2", "tmp");

        Assert.assertTrue(a.isFile());
        Assert.assertTrue(b.isFile());

        try {
            FileUtils.write(a, "Hello world".getBytes("UTF-8"));
            FileUtils.copy(a, b);

            byte[] data = FileUtils.readAllBytes(b);
            Assert.assertNotNull(data);

            String s = new String(data, "UTF-8");
            Assert.assertEquals("Hello world", s);
        } finally {
            boolean ignored = a.delete();
            ignored = b.delete();
        }
    }