I’m trying to learn and implement jest unit tests on a few existing projects.

We have multiple React apps with a shared utilities file that is one level up each project root folder.

import utils from '../../../utilities';

I’m getting this message:

Cannot find module ‘../../../utilities’ from ‘src/features/component.jsx’

I have tried to add “../” to the roots parameter in config. I’ve tried a few other entries in the roots array but can’t get this to work.

const config = {
    roots:[
        "<rootDir>",
        "../"
    ],
    moduleNameMapper: {
        '\.(png)$': 'identity-obj-proxy', //'<rootDir>/__mocks__/fileMock.js',
        '\.(css|less)$': 'identity-obj-proxy',
    },
    moduleDirectories:["node_modules", "src"],
    transform: {
        '^.+\.(js|jsx)$': 'babel-jest'
    },
    testEnvironment: 'node',
};

module.exports = config;

I have tried mocking the utils; but I might be doing this wrong.

jest.mock('utilities', () => ({}));

This gives me this message:

Cannot find module ‘utilities’ from ‘src/features/component.spec.js’

The utilities is just a few shared functions, has been carried over for years and is formatted as:

let utils = {
...
};

export default utils;

• Would we need to copy utilities for each react app?
• Or is there a way to keep a single shared utilities file and include it in our jest tests?
• Or is there a different work around to get some unit tests with a single utilities file?