TypeError: $.extend is not a function

Hi, i just use toastr for a few days. I have problem when testing my action (react). Here’s the error:

TypeError: $.extend is not a function
      at getOptions (node_modules/toastr/toastr.js:452:26)
      at Object.error (node_modules/toastr/toastr.js:49:32)
      at static/js/actions/action_coa.js:17:14
      at <anonymous>

I’m using mocha, chai and nock Here’s my test code:

it('should create a FETCH_ALL_COA action', () => {
    nock(`http://${ROOT_URL}`)
      .get('api/coa/?format=json')
      .reply(200, dummy_coa);

    const store = mockStore({ coa: {} });
    let expectedAction = [{ type: FETCH_ALL_COA, payload: [{
      ...dummy_coa
    }]}];
    return store.dispatch(fetchAllCOA())
      .then(() => {
        expect(store.getActions()).to.eql(expectedAction);
      });
  });

beside this error, it also give a warning on my console (testing result ):

(node:2758) UnhandledPromiseRejectionWarning: Unhandled promise rejection (rejection id: 745): TypeError: $.extend is not a function

my action code:

import axios from 'axios';
import {ROOT_URL, FETCH_ALL_COA, FETCH_COA, DELETE_COA} from './types.js';
import toastr from '../components/my_toastr.js';

export function fetchAllCOA(token){
  const url = `${ROOT_URL}api/coa/?format=json`;
  const request = axios.get(url, {headers:{Authorization:token}});
  return (dispatch => {
    return request.then(data => {
      dispatch({type: FETCH_ALL_COA, payload: data.data});
    }).catch(() => {
      toastr.error('Can\'t connect to server!<br />' + 
        'Please check your internet connection', 'Error!');
    });
  });
}

Pardon my English, it’s not my native language.

Please help me, wether i made some mistakes or did i miss something. Thank you