Testing React Redux Async Actions with fetch-mock - "Cannot read property 'then' of undefined"

Question

I have some problems with testing react redux async actions, for some reason store.dispatch returns undefined and .then method doesn't work.

When I console.log the store.dispatch(actions.requestChartData()) it gives me the following error:

fetch-mock: No fallback response defined for GET to https://swapi.co/api/people

witch means that there is no mock response and it's undefined.

I don't know where is my mistake, in the url or something that i'm missing. Any help will be appreciated

Here're my action.js code:

import {
    ROOT_URL,
    API_KEY,
    FETCH_POSTS,
    CREATE_POST,
    REQUEST_CHART_DATA_PENDING,
    REQUEST_CHART_DATA_SUCCESS,
    REQUEST_CHART_DATA_FAILED
} from '../constants/constants'

export const requestChartData = () => (dispatch) => {
    dispatch({type: REQUEST_CHART_DATA_PENDING})

    fetch('https://swapi.co/api/people')
        .then(response => response.json())
        .then(data => dispatch({type: REQUEST_CHART_DATA_SUCCESS, 
                labels: data.results.map(label => label.name),
                chartData: data.results.map(chartData => chartData.height )}))

        .catch(error => dispatch({type: REQUEST_CHART_DATA_FAILED, payload: error}))        
}

And my action.test.js file:

import * as actions from '../../actions/index'
import fetchMock from 'fetch-mock'
import {
    ROOT_URL,
    API_KEY,
    FETCH_POSTS,
    CREATE_POST,
    REQUEST_CHART_DATA_PENDING,
    REQUEST_CHART_DATA_SUCCESS,
    REQUEST_CHART_DATA_FAILED
} from '../../constants/constants'

import thunkMiddleware from 'redux-thunk'
import configureMockStore from 'redux-mock-store'

const mockStore = configureMockStore([thunkMiddleware])

describe('fetching api url', () => {
 afterEach(() => {
   fetchMock.restore()
 })

 it('creates REQUEST_CHART_DATA_SUCCESS when fetching has been done', () => {
   fetchMock.getOnce('https://swapi.co/api/people', {
  body: { todos: ['do something'] },
  headers: { 'content-type': 'application/json' }
   })
  
   const expectedActions = 
  { type: REQUEST_CHART_DATA_SUCCESS, body: { todos: ['do something'] } }
 
   const store = mockStore({ todos: [] })
  
   return store.dispatch(actions.requestChartData()).then(() => {
  
  expect(store.getActions()).toEqual(expectedActions)
   })
  })
  })

Answer 1

In your requestChartData action creator, return the fetch instead of just calling it. return fetch('/your-api-path')