### Question:
RemoteValidatorApiHandler implements ValidatorApiChannel { @Override public void sendSignedBlock(final SignedBeaconBlock block) { asyncRunner .runAsync( () -> apiClient.sendSignedBlock( new tech.pegasys.teku.api.schema.SignedBeaconBlock(block))) .finish(error -> LOG.error("Failed to send signed block", error)); ; } RemoteValidatorApiHandler(final ServiceConfig config, final AsyncRunner asyncRunner); @VisibleForTesting  RemoteValidatorApiHandler(
      final ValidatorRestApiClient apiClient, final AsyncRunner asyncRunner); @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<Attestation>> createUnsignedAttestation(
      final UInt64 slot, final int committeeIndex); @Override void sendSignedAttestation(final Attestation attestation); @Override void sendSignedAttestation(
      final Attestation attestation, final Optional<Integer> validatorIndex); @Override SafeFuture<Optional<BeaconBlock>> createUnsignedBlock(
      final UInt64 slot, final BLSSignature randaoReveal, final Optional<Bytes32> graffiti); @Override void sendSignedBlock(final SignedBeaconBlock block); @Override SafeFuture<Optional<Attestation>> createAggregate(final Bytes32 attestationHashTreeRoot); @Override void sendAggregateAndProof(final SignedAggregateAndProof aggregateAndProof); @Override void subscribeToBeaconCommitteeForAggregation(
      final int committeeIndex, final UInt64 aggregationSlot); @Override void subscribeToPersistentSubnets(final Set<SubnetSubscription> subnetSubscriptions);  }### Answer:
@Test public void sendSignedBlock_InvokeApiWithCorrectRequest() { final BeaconBlock beaconBlock = dataStructureUtil.randomBeaconBlock(UInt64.ONE); final BLSSignature signature = dataStructureUtil.randomSignature(); final SignedBeaconBlock signedBeaconBlock = new SignedBeaconBlock(beaconBlock, signature); final tech.pegasys.teku.api.schema.SignedBeaconBlock schemaSignedBlock = new tech.pegasys.teku.api.schema.SignedBeaconBlock(signedBeaconBlock); ArgumentCaptor<tech.pegasys.teku.api.schema.SignedBeaconBlock> argumentCaptor = ArgumentCaptor.forClass(tech.pegasys.teku.api.schema.SignedBeaconBlock.class); apiHandler.sendSignedBlock(signedBeaconBlock); asyncRunner.executeQueuedActions(); verify(apiClient).sendSignedBlock(argumentCaptor.capture()); assertThat(argumentCaptor.getValue()).usingRecursiveComparison().isEqualTo(schemaSignedBlock); }