message: tests: fix issue-177 test not testing for null correctly
diff: import { Curl } from '../../lib'
  +import should from 'should'
  +
  describe('issues', function () {
  this.timeout(20000)
  @@ -34,7 +36,7 @@ describe('issues', function () {
  error = _error
  }
  - error.should.not.be.equal(null)
  + should(error).not.be.equal(null)
  const promiseResolvedTime = process.hrtime(testStartTime)
  promiseResolvedTime[0].should.be.lessThan(2)
  