mocking a react hook

gistfile1.txt

I'll start at the highest level and go in.
the relevant part of the react component that calls the custom hook:
//////////////
//product.js//
//////////////

///////////////////////////
//useProductDetailData.js//
///////////////////////////

import React, {
  Fragment,
  useState,
  useEffect,
  useReducer,
} from 'react';
import axios from 'axios';
import useGlobal from '../../store/store'

/**
 * Custom hook to get data from endpoints.
 * @param state
 * @param action
 * @returns {{isLoading: boolean, isError: boolean, data: *}|{isLoading: boolean, isError: boolean}}
 */
const dataFetchReducer = (state, action) => {
  switch (action.type) {
    case 'FETCH_INIT':
      return {
        ...state,
        isLoading: true,
        isError: false,
        isExpired: false,
      };
    case 'FETCH_SUCCESS':
      return {
        ...state,
        isLoading: false,
        isError: false,
        isExpired: false,
        data: action.payload,
      };
    case 'FETCH_FAILURE':
      return {
        ...state,
        isLoading: false,
        isError: true,
        isExpired: false,
      };
    case 'FETCH_EXPIRED':
      return {
        ...state,
        isLoading: false,
        isError: false,
        isExpired: true,
      };
    default:
      throw new Error();
  }
};

const useProductDetailData = (initialUrl, initialData) => {
  const [globalState, globalActions] = useGlobal();
  const [url, setUrl] = useState(initialUrl);

  const [state, dispatch] = useReducer(dataFetchReducer, {
    isLoading: false,
    isError: false,
    isExpired: false,
    data: initialData,
  });

  useEffect(() => {
    let didCancel = false;
    const fetchData = async () => {
      dispatch({ type: 'FETCH_INIT' });
      try {
        const result = await axios(
          url,
          {
            'headers': {
              "Accept": "application/json",
              'Authorization': "Bearer " + globalState.token,
            }
          });
        if (!didCancel) {
          dispatch({ type: 'FETCH_SUCCESS', payload: result.data });
        }
      } catch (error) {
        if (!didCancel) {
          if (
            error && error.response && error.response.status === 401
          ){
            dispatch({type: 'FETCH_EXPIRED'})
          } else {
            dispatch({ type: 'FETCH_FAILURE' });
          }
        }
      }
    };

    fetchData();

    return () => {
      didCancel = true;
    };
  }, [globalState.token, url]);

  return [state, setUrl];
};

export default useProductDetailData;