message: test(hbar): add tests
diff: @@ -3,6 +3,7 @@ import * as accountLib from '@bitgo/account-lib';
  import { TestBitGo } from '../../../lib/test_bitgo';
  import { rawTransactionForExplain } from '../../fixtures/coins/hbar';
  +import { randomBytes } from 'crypto';
  describe('Hedera Hashgraph:', function() {
  let bitgo;
  @@ -98,6 +99,21 @@ describe('Hedera Hashgraph:', function() {
  });
  });
  + describe('Sign Message', () => {
  + it('should be performed', async () => {
  + const keyPair = new accountLib.Hbar.KeyPair();
  + const messageToSign = Buffer.from(randomBytes(32)).toString('hex');
  + const signature = await basecoin.signMessage(keyPair.getKeys(), messageToSign);
  + keyPair.verifySignature(messageToSign, Uint8Array.from(Buffer.from(signature, 'hex'))).should.equals(true);
  + });
  +
  + it('should fail with missing private key', async () => {
  + const keyPair = new accountLib.Hbar.KeyPair({ pub: '302a300506032b6570032100d8fd745361df270776a3ab1b55d5590ec00a26ab45eea37197dc9894a81fcb82' }).getKeys();
  + const messageToSign = Buffer.from(randomBytes(32)).toString('hex');
  + await basecoin.signMessage(keyPair, messageToSign).should.be.rejectedWith('Invalid key pair options');
  + });
  + });
  +
  describe('Sign transaction:', () => {
  /**
  * Build an unsigned account-lib multi-signature send transaction
  