@Test
public void formatMD5() {

    byte[] md5 = {0x01, 0x39, (byte) 0xef, (byte) 0xc1, (byte) 0xe9, (byte) 0x86, 0x22, 0x33, 0x74, 0x3a, 0x75, 0x77, (byte) 0x98, (byte) 0xdd, (byte) 0x9c};
    String expected = "0139efc1e9862233743a757798dd9c";
    String actual = Strings.formatMD5(md5, true);
    assertEquals ("bytes", expected, actual);
}