import moment from 'moment-timezone';

class TimezoneCityItem extends React.Component {

  componentDidMount(){
    this.setState({
      time: moment.tz(this.props.timezone)
    })
  }

  render(){
    return (
      <div>{this.state.time.format('HH:mm')}</div>
    )
  }
}

import React from 'react';
import { shallow } from 'enzyme';
import TimezoneCityItem from '../TimezoneCity.item';
import timezoneList from '/lib/timezoneListDummyData'; // It just an array list of timezone

describe('<TimezoneCityItem />', () => {
   test('Should render TimezoneCityItem correctly', () => {
   const wrapper = shallow(<TimezoneCityItem {...timezoneList[0]} />);
   expect(wrapper).toMatchSnapshot();
});

"moment": "~2.18.1",
"moment-timezone": "~0.5.13",

TypeError: Cannot read property 'split' of undefined

  at node_modules/moment-timezone/moment-timezone.js:36:34
  at Object.<anonymous>.moment (node_modules/moment-timezone/moment-timezone.js:14:20)
  at Object.<anonymous> (node_modules/moment-timezone/moment-timezone.js:18:2)
  at Object.<anonymous> (node_modules/moment-timezone/index.js:1:120)
  at Object.<anonymous> (imports/ui/components/mainLayout/TimezoneCity.item.jsx:3:49)
  at Object.<anonymous> (imports/ui/components/mainLayout/TimezoneCity.jsx:3:47)
  at Object.<anonymous> (imports/ui/components/mainLayout/MainLayout.jsx:6:47)
  at Object.<anonymous> (imports/ui/components/mainLayout/__tests__/MainLayout.test.js:3:19)
      at Generator.next (<anonymous>)
      at new Promise (<anonymous>)
      at Generator.next (<anonymous>)
      at <anonymous>