Jest test throws "Cannot read property 'prototype' of undefined" when tested action returns a call to fetch - reactjs

Question

I'm trying to debug a Jest test in a React/Redux app; I'm running the following test (I haven't implemented faker yet).
it("Should create a SUBMIT_CONTACT_ME_FORM_SUCCESS action when contact me form submission completes successfully.", () => {
const contactMe = {
id: 1,
name: "John Shepard",
email: "shepard#n7.gov",
comments: "I am not the very model of a scientist salarian."
};
fetchMock.postOnce(contactMeURL, {
headers: { "content-type": "application/json" },
body: contactMe
});
const expectedActions = [
{
type: navbarActions.SUBMIT_CONTACT_ME_FORM_REQUEST,
contactMeForm
},
{
type: navbarActions.SUBMIT_CONTACT_ME_FORM_SUCCESS,
contactMe,
receivedAt: 1
}
;
const store = mockStore({ contactMe: null });
return store.dispatch(navbarActions.submitContactMeForm(contactMeForm, 1))
.then(() => {
expect(store.getActions()).toEqual(expectedActions);
});
});
However, my logs point to the beginning of the fetch in the following statement within the tested action.
return fetch(`${apiRoot}/contact`, {
method: "POST",
headers: {
"Content-Type": "application/json"
},
body: JSON.stringify(contactMeForm)
})
.then(response => response.json())
.then(json => {
if (json.err) {
dispatch(submitContactMeFormFailure(json.err, forcedTime))
} else {
dispatch(submitContactMeFormSuccess(json, forcedTime))
}
});
It seems to be a timing/lifecycle issue, but I can't isolate or correct it. I'm using the following dev dependencies.
"devDependencies": {
"enzyme": "^3.11.0",
"enzyme-adapter-react-16": "^1.15.6",
"fetch-mock": "^9.11.0",
"jasmine": "^3.9.0",
"jasmine-enzyme": "^7.1.2",
"node-fetch": "^3.0.0",
"redux-mock-store": "^1.5.4"
}

Answer 1

This might not be the answer but try running your test with async
it("Should ... successfully.", async() => {
const contactMe = {
id: 1,
name: "John Shepard",
email: "shepard#n7.gov",
comments: "I am not the very model of a scientist salarian."
};
fetchMock.postOnce(contactMeURL, {
headers: { "content-type": "application/json" },
body: contactMe
});
const expectedActions = [
{
type: navbarActions.SUBMIT_CONTACT_ME_FORM_REQUEST,
contactMeForm
},
{
type: navbarActions.SUBMIT_CONTACT_ME_FORM_SUCCESS,
contactMe,
receivedAt: 1
};
const store = mockStore({ contactMe: null });
await store.dispatch(navbarActions.submitContactMeForm(contactMeForm, 1));
expect(store.getActions()).toEqual(expectedActions);
});