crypto module mock

crypto.js

const crypto = jest.requireActual('crypto');
const Chance = require('chance');

const chances = {};

const mockCrypto = Object.create(crypto);
mockCrypto.randomBytes = (size, seed = 42, callback) => {
  if (typeof seed === 'function') {
    // eslint-disable-next-line no-param-reassign
    callback = seed;
    // eslint-disable-next-line no-param-reassign
    seed = 42;
  }

  chances[seed] = chances[seed] || new Chance(seed);
  const chance = chances[seed];

  const randomByteArray = chance.n(chance.natural, size, { max: 255 });
  const buffer = Buffer.from(randomByteArray);

  if (typeof callback === 'function') {
    callback(null, buffer);
  }
  return buffer;
};

module.exports = mockCrypto;