@Test public void testByte(){
  HexEncoder encoder=new HexEncoder();
  assertEquals("12",new String(encoder.encodeByte((byte)0x12),Charset.defaultCharset()));
  assertEquals("f2",new String(encoder.encodeByte((byte)0xf2),Charset.defaultCharset()));
  byte b=Byte.MIN_VALUE;
  while (b != Byte.MAX_VALUE) {
    assertEquals(b,encoder.decodeByte(encoder.encodeByte(b)));
    b++;
  }
}