### Question:
IbftBlockHashing { public static Hash calculateHashOfIbftBlockOnChain(final BlockHeader header) { final IbftExtraData ibftExtraData = IbftExtraData.decode(header); return Hash.hash( serializeHeader(header, ibftExtraData::encodeWithoutCommitSealsAndRoundNumber)); }  static Hash calculateDataHashForCommittedSeal(
      final BlockHeader header, final IbftExtraData ibftExtraData); static Hash calculateDataHashForCommittedSeal(final BlockHeader header); static Hash calculateHashOfIbftBlockOnChain(final BlockHeader header); static List<Address> recoverCommitterAddresses(
      final BlockHeader header, final IbftExtraData ibftExtraData);  }### Answer:
@Test public void testCalculateHashOfIbft2BlockOnChain() { Hash actualHeaderHash = IbftBlockHashing.calculateHashOfIbftBlockOnChain(HEADER_TO_BE_HASHED); assertThat(actualHeaderHash).isEqualTo(EXPECTED_HEADER_HASH); }