### Question:
DefaultMutableWorldState implements MutableWorldState { @Override public Stream<StreamableAccount> streamAccounts(final Bytes32 startKeyHash, final int limit) { return accountStateTrie.entriesFrom(startKeyHash, limit).entrySet().stream() .map( entry -> { final Optional<Address> address = getAccountTrieKeyPreimage(entry.getKey()); final AccountState account = deserializeAccount( address.orElse(Address.ZERO), Hash.wrap(entry.getKey()), entry.getValue()); return new StreamableAccount(address, account); }); } DefaultMutableWorldState(
      final WorldStateStorage storage, final WorldStatePreimageStorage preimageStorage);  DefaultMutableWorldState(
      final Bytes32 rootHash,
      final WorldStateStorage worldStateStorage,
      final WorldStatePreimageStorage preimageStorage);  DefaultMutableWorldState(final WorldState worldState); @Override Hash rootHash(); @Override MutableWorldState copy(); @Override Account get(final Address address); @Override WorldUpdater updater(); @Override Stream<StreamableAccount> streamAccounts(final Bytes32 startKeyHash, final int limit); @Override int hashCode(); @Override final boolean equals(final Object other); @Override void persist();  }### Answer:
@Test public void streamAccounts_empty() { final MutableWorldState worldState = createEmpty(); final Stream<StreamableAccount> accounts = worldState.streamAccounts(Bytes32.ZERO, 10); assertThat(accounts.count()).isEqualTo(0L); }