return new byte[8];
          }

          @Override
          public String getFormat() {
            return "RAW";
          }
        };
    assertEquals(
        "ad262969c53bc16032f160081c4a07a0",
        Hashing.hmacMd5(customKey)
            .hashString("The quick brown fox jumps over the lazy dog", UTF_8)
            .toString());
  }

  public void testBadKey_emptyKey() throws Exception {