### Question:
ValidatorApiHandler implements ValidatorApiChannel { @Override public SafeFuture<Optional<ForkInfo>> getForkInfo() { return SafeFuture.completedFuture( combinedChainDataClient.getBestState().map(BeaconState::getForkInfo)); } ValidatorApiHandler(
      final CombinedChainDataClient combinedChainDataClient,
      final SyncStateTracker syncStateTracker,
      final StateTransition stateTransition,
      final BlockFactory blockFactory,
      final AggregatingAttestationPool attestationPool,
      final AttestationManager attestationManager,
      final AttestationTopicSubscriber attestationTopicSubscriber,
      final EventBus eventBus,
      final DutyMetrics dutyMetrics,
      final PerformanceTracker performanceTracker); @Override SafeFuture<Optional<ForkInfo>> getForkInfo(); @Override SafeFuture<Optional<UInt64>> getGenesisTime(); @Override SafeFuture<Optional<List<ValidatorDuties>>> getDuties(
      final UInt64 epoch, final Collection<BLSPublicKey> publicKeys); @Override SafeFuture<Optional<List<AttesterDuties>>> getAttestationDuties(
      final UInt64 epoch, final Collection<Integer> validatorIndexes); @Override SafeFuture<Optional<List<ProposerDuties>>> getProposerDuties(final UInt64 epoch); @Override SafeFuture<Optional<BeaconBlock>> createUnsignedBlock(
      final UInt64 slot, final BLSSignature randaoReveal, final Optional<Bytes32> graffiti); @Override SafeFuture<Optional<Attestation>> createUnsignedAttestation(
      final UInt64 slot, final int committeeIndex); @Override SafeFuture<Optional<Attestation>> createAggregate(final Bytes32 attestationHashTreeRoot); @Override void subscribeToBeaconCommitteeForAggregation(
      final int committeeIndex, final UInt64 aggregationSlot); @Override void subscribeToPersistentSubnets(Set<SubnetSubscription> subnetSubscriptions); @Override void sendSignedAttestation(
      final Attestation attestation, final Optional<Integer> expectedValidatorIndex); @Override void sendSignedAttestation(final Attestation attestation); @Override void sendAggregateAndProof(final SignedAggregateAndProof aggregateAndProof); @Override void sendSignedBlock(final SignedBeaconBlock block);  }### Answer:
@Test public void getFork_shouldReturnEmptyWhenHeadStateNotAvailable() { when(chainDataClient.getBestState()).thenReturn(Optional.empty()); assertThat(validatorApiHandler.getForkInfo()).isCompletedWithValue(Optional.empty()); }
@Test public void getFork_shouldReturnForkFromHeadState() { final BeaconState state = dataStructureUtil.randomBeaconState(); when(chainDataClient.getBestState()).thenReturn(Optional.of(state)); assertThat(validatorApiHandler.getForkInfo()) .isCompletedWithValue(Optional.of(state.getForkInfo())); }