How do we mock fetch in Redux Async Actions?

Question

In the Writing Tests section of Redux,http://rackt.org/redux/docs/recipes/WritingTests.html, how does the store.dispatch(actions.fetchTodos()) not invoke the fetch method, if store.dispatch is literally calling actions.fetchTodos?

it('creates FETCH_TODOS_SUCCESS when fetching todos has been done', (done) => {
    nock('http://example.com/')
      .get('/todos')
      .reply(200, { todos: ['do something'] })

const expectedActions = [
  { type: types.FETCH_TODOS_REQUEST },
  { type: types.FETCH_TODOS_SUCCESS, body: { todos: ['do something']  } }
]
const store = mockStore({ todos: [] }, expectedActions, done)
store.dispatch(actions.fetchTodos())


})

Everytime I try to run something similar to this, I keep getting a fetch is not defined. Even if I use nock. So I have to spy my action to not get the call to fetch.

Here is my unit test:

it('should request a password reset, and then return success on 200', (done) => {
        nock('http://localhost:8080/')
        .post('/password-reset-requests')
        .reply(200);


var email = "test@email.com";
        const expectedActions=[
            {type: REQUEST_ADD_PASSWORD_RESET_REQUEST},
            {type: REQUEST_ADD_PASSWORD_RESET_REQUEST_SUCCESS}
        ];
        const store = mockStore({}, expectedActions, done);
        store.dispatch(Actions.addPasswordResetRequest());

here is the action:

export default function addPasswordResetRequest(email){
    return dispatch => {
        dispatch(requestAddPasswordResetRequest(email));
        return addPasswordResetRequestAPI(email)
            .then(() =>{
                dispatch(requestAddPasswordResetRequestSuccess());
            })
            .catch((error) => {
            dispatch(requestAddPasswordResetRequestFailure(error));
        });
    };
}

and the function that calls fetch:

export const addPasswordResetRequestAPI = (email) => {
    return fetch(
        SETTINGS.API_ROOT + '/password-reset-requests',
        {
            method: 'POST',
            headers: {
                'Content-Type': 'application/json'
            },
            body: JSON.stringify({
                email: email,
                code: NC_SETTINGS.GROUP.code
            })
        }
    )
        .then(handleResponse);
};

I'm not sure if the way I am doing is sufficient for the purpose of just testing actions, but then I do run into the problem of store.dispatch only returning the first element of expectedActions, and it doesn't equal the list I supply in the spied addPasswordResetRequest. Below includes the spied action.

it('should request a password reset, and then return success on 200', (done) => {
        nock('http://localhost:8080/')
        .post('/password-reset-requests')
        .reply(200);
        Actions.addPasswordResetRequest = spy(() => {
    return ([
            {type: REQUEST_ADD_PASSWORD_RESET_REQUEST},
            {type: REQUEST_ADD_PASSWORD_RESET_REQUEST_SUCCESS}
        ]
        );
});
        var email = "test@email.com";
        const expectedActions=[
            {type: REQUEST_ADD_PASSWORD_RESET_REQUEST},
            {type: REQUEST_ADD_PASSWORD_RESET_REQUEST_SUCCESS}
        ];

        const store = mockStore({}, expectedActions, done);
        store.dispatch(Actions.addPasswordResetRequest());

Answer 1

The action "addPasswordResetRequest" isn't an action per-say.

it's a composite action with 3 sub-actions

startAction   =requestAddPasswordResetRequest,
successAction =requestAddPasswordResetRequestSuccess 
failAction    =requestAddPasswordResetRequestFailure

I generally tests each action separately. so i would have something like

describe("requestAddPasswordResetRequest", () => {
     it("shows the loading spinner or whatever", ...);
     it("does some other state change maybe", ...);
});
describe("requestAddPasswordResetRequestSuccess", () => {
     it("hides the loading spinner or whatever", ...);
     it("changes the password state or something", ...);
});
describe("requestAddPasswordResetRequestFailure", () => {
     it("hides the loading spinner or whatever", ...);
     it("shows the error somehow", ...);
});

//each test would be something like
it("changes the password state or something", ()=>{
    const action = requestAddPasswordResetRequestSuccess({
          some : "payload from the server"
    });
    const newState = myReducer({ state : "somestate" }, action);
    expect(newState).to.be.eql("expected result for that action"); 
});

Notice how in the test i don't need the store or any async logic. thats the beauty of redux (and functional stuff in general), it's simple :)

after this i would have a separate test for the whole thing and make sure that the correct simple actions get dispatched by the composite action, in which i would mock everything (including store and the "fetch" thing, since i just want to test that the actions get fired in the correct order).

if the actions are dispatched in the correct order and each action work separably i would be pretty confident that the thing works as expected.

Hope this helps.