### Question:
IbftLegacyBlockInterface implements BlockInterface { public static BlockHeaderBuilder insertVoteToHeaderBuilder( final BlockHeaderBuilder builder, final Optional<ValidatorVote> vote) { if (vote.isPresent()) { final ValidatorVote voteToCast = vote.get(); builder.nonce(voteToValue.get(voteToCast.getVotePolarity())); builder.coinbase(voteToCast.getRecipient()); } else { builder.nonce(voteToValue.get(VoteType.DROP)); builder.coinbase(NO_VOTE_SUBJECT); } return builder; }  @Override Address getProposerOfBlock(final BlockHeader header); @Override Address getProposerOfBlock(final org.hyperledger.besu.plugin.data.BlockHeader header); @Override Optional<ValidatorVote> extractVoteFromHeader(final BlockHeader header); static BlockHeaderBuilder insertVoteToHeaderBuilder(
      final BlockHeaderBuilder builder, final Optional<ValidatorVote> vote); @Override Collection<Address> validatorsInBlock(final BlockHeader header); static boolean isValidVoteValue(final long value); static final Address NO_VOTE_SUBJECT; static final long ADD_NONCE; static final long DROP_NONCE; }### Answer:
@Test public void blendingAddVoteToHeaderResultsInHeaderWithNonceOfMaxLong() { final ValidatorVote vote = new ValidatorVote(ADD, AddressHelpers.ofValue(1), AddressHelpers.ofValue(2)); final BlockHeaderBuilder builderWithVote = IbftLegacyBlockInterface.insertVoteToHeaderBuilder(builder, Optional.of(vote)); final BlockHeader header = builderWithVote.buildBlockHeader(); assertThat(header.getCoinbase()).isEqualTo(vote.getRecipient()); assertThat(header.getNonce()).isEqualTo(0xFFFFFFFFFFFFFFFFL); }
@Test public void blendingDropVoteToHeaderResultsInHeaderWithNonceOfZero() { final ValidatorVote vote = new ValidatorVote(DROP, AddressHelpers.ofValue(1), AddressHelpers.ofValue(2)); final BlockHeaderBuilder builderWithVote = IbftLegacyBlockInterface.insertVoteToHeaderBuilder(builder, Optional.of(vote)); final BlockHeader header = builderWithVote.buildBlockHeader(); assertThat(header.getCoinbase()).isEqualTo(vote.getRecipient()); assertThat(header.getNonce()).isEqualTo(0x0L); }
@Test public void nonVoteBlendedIntoHeaderResultsInACoinbaseOfZero() { final BlockHeaderBuilder builderWithVote = IbftLegacyBlockInterface.insertVoteToHeaderBuilder(builder, Optional.empty()); final BlockHeader header = builderWithVote.buildBlockHeader(); assertThat(header.getCoinbase()).isEqualTo(AddressHelpers.ofValue(0)); assertThat(header.getNonce()).isEqualTo(0x0L); }