### Question:
IbftGetValidatorsByBlockNumber extends AbstractBlockParameterMethod implements JsonRpcMethod { @Override protected BlockParameter blockParameter(final JsonRpcRequestContext request) { return request.getRequiredParameter(0, BlockParameter.class); } IbftGetValidatorsByBlockNumber(
      final BlockchainQueries blockchainQueries, final BlockInterface blockInterface); @Override String getName();  }### Answer:
@Test public void blockParameterIsParameter0() { request = new JsonRpcRequestContext(new JsonRpcRequest("?", "ignore", new String[] {"0x1245"})); BlockParameter blockParameter = method.blockParameter(request); assertThat(blockParameter.getNumber()).isPresent(); assertThat(blockParameter.getNumber().get()).isEqualTo(0x1245); }