opinion-ateTDD_personal/src/store/restaurants.spec.js

import { createStore, applyMiddleware } from "redux";
import thunk from 'redux-thunk';
import restaurantReducer from './restaurants/reducers';
import { loadRestaurants } from "./restaurants/actions";

describe('restaurants', () =>
{
    describe('initially', () =>
    {
        let store;

        beforeEach(() =>
        {
            const initialState = {};
            store = createStore(
                restaurantReducer,
                initialState,
                applyMiddleware(thunk),
            );
        });
        it('does not have the loading flag set', () =>
        {
            expect(store.getState().loading).toEqual(false);
        });
        it('does not have the error flag set', () =>
        {
            expect(store.getState().loadError).toEqual(false);
        });
    });
    describe('loadRestaurants Action', () =>
    {
        describe('When Loading Succeeds', () =>
        {
            const records = [
                { id: 1, name: 'Sushi Place' },
                { id: 2, name: 'Pizza Place' }
            ];
            let store;

            beforeEach(() =>
            {
                const api = {
                    loadRestaurants: () => Promise.resolve(records),
                };
                const initialState = {
                    records: [],
                };
                store = createStore(
                    restaurantReducer,
                    initialState,
                    applyMiddleware(
                        thunk.withExtraArgument(api),
                    ),
                );
                return store.dispatch(loadRestaurants());
            })

            it('stores the restaurants', async () =>
            {
                expect(store.getState().records).toEqual(records)
            });
            it('clears the loading flag', () =>
            {
                expect(store.getState().loading).toEqual(false);
            });
        });
        describe('While Loading', () =>
        {
            let store;

            beforeEach(() =>
            {
                const api = {
                    loadRestaurants: () => new Promise(() => { }),
                }
                const initialState = { loadError: true };
                store = createStore(
                    restaurantReducer,
                    initialState,
                    applyMiddleware(
                        thunk.withExtraArgument(api),
                    ),
                );
                store.dispatch(loadRestaurants());
            });
            it('sets a loading flag', () =>
            {
                expect(store.getState().loading).toEqual(true);
            });
            it('clears the error flag', () =>
            {
                expect(store.getState().loadError).toEqual(false);
            });
        });
        describe('When Loading Fails', () =>
        {
            let store;

            beforeEach(() =>
            {
                const api = {
                    loadRestaurants: () => Promise.reject(),
                };

                const initialState = {};

                store = createStore(
                    restaurantReducer,
                    initialState,
                    applyMiddleware(
                        thunk.withExtraArgument(api),
                    ),
                );
                return store.dispatch(loadRestaurants());
            });

            it('sets an error flag', () =>
            {
                expect(store.getState().loadError).toEqual(true);
            });
            it('clears the loading flag', () =>
            {
                expect(store.getState().loading).toEqual(false);
            });
        });
    });
});