Service mocked with Jest causes “The module factory of jest.mock() is not allowed to reference any out-of-scope variables” error

Question

I\'m trying to mock a call to a service but I\'m struggeling with the following message: The module factory of jest.mock() is not allowed to reference a

Answer 1

This is how I would solve it for your code.

You need to store your mocked component in a variable with a name prefixed by "mock". This solution is based on the Note at the end of the error message I was getting.

Note: This is a precaution to guard against uninitialized mock variables. If it is ensured that the mock is required lazily, variable names prefixed with mock are permitted.

import {shallow} from 'enzyme';
import React from 'react';
import Vocabulary from "../../../src/components/Vocabulary ";
import {VocabularyEntry} from '../../../src/model/VocabularyEntry'

const mockVocabulary = () => new VocabularyEntry("a", "a1");

jest.mock('../../../src/services/vocabularyService', () => ({
    default: mockVocabulary
}));

describe("Vocabulary tests", () => {

test("renders the vocabulary", () => {

    let $component = shallow();

    // expect something

});