public String toString()
    {
        return toString(data);
    }
@Test
    public void testToStringNonPrintable()
    {
        byte[] buf = new byte[2];
        Arrays.fill(buf, (byte) 0x04);
        ZData data = new ZData(buf);

        String string = data.toString();
        assertThat(string, is("0404"));
    }