message: Add: ledger class `sign()` input unit tests
diff: +import { userInputValidator } from '../../core/helpers';
  import LedgerWalletClass from '../../ledger/class';
  import {
  signTransaction,
  @@ -5,6 +6,7 @@ import {
  verifyMessage,
  } from '../../ledger/staticMethods';
  +import { REQUIRED_PROPS } from '../../core/defaults';
  import { TYPE_HARDWARE, SUBTYPE_LEDGER } from '../../core/types';
  jest.dontMock('../../ledger/class');
  @@ -12,6 +14,7 @@ jest.dontMock('../../ledger/class');
  jest.mock('../../ledger/staticMethods');
  jest.mock('../../core/validators');
  jest.mock('../../core/normalizers');
  +jest.mock('../../core/helpers');
  /*
  * Common values
  @@ -27,6 +30,11 @@ const mockedInstanceArgument = {
  rootDerivationPath,
  addressCount,
  };
  +const mockedTransactionObject = {
  + to: 'mocked-address',
  + nonce: 'mocked-nonce',
  + value: 'mocked-transaction-value',
  +};
  describe('Ledger` Hardware Wallet Module', () => {
  describe('`LedgerWallet` class', () => {
  @@ -105,6 +113,18 @@ describe('Ledger` Hardware Wallet Module', () => {
  }));
  },
  );
  + test('Validates `sign` method user input', async () => {
  + const trezorWallet = new LedgerWalletClass(mockedInstanceArgument);
  + await trezorWallet.sign(mockedTransactionObject);
  + /*
  + * Validate the input
  + */
  + expect(userInputValidator).toHaveBeenCalled();
  + expect(userInputValidator).toHaveBeenCalledWith({
  + firstArgument: mockedTransactionObject,
  + requiredAll: REQUIRED_PROPS.SIGN_TRANSACTION,
  + });
  + });
  test(
  "Calls the `signMessage()` static method from the instance's methods",
  async () => {
  