Mocking node modules using typescript

index.test.ts

import { mocked } from 'ts-jest/utils';
import fetch, { Response } from 'node-fetch';

import { test } from './index';

jest.mock('node-fetch');

it('It works', async () => {
  console.log = jest.fn();

  mocked(fetch).mockImplementation(() =>
    Promise.resolve({
      json: () => Promise.resolve({ results: [{ name: { first: 'Bob' } }] }),
    } as Response)
  );

  await test();

  expect(console.log).toHaveBeenCalledWith('Hello Bob');
});

index.ts

import fetch from 'node-fetch'

export async function test() {
  const result = await fetch('https://randomuser.me/api/');
  const data = await result.json()

  console.log(`Hello ${data.results[0].name.first}`)
}

jest.config.js

module.exports = {
  preset: 'ts-jest',
  testEnvironment: 'node',
};

package.json

{
  "name": "ts-test",
  "version": "1.0.0",
  "main": "index.js",
  "license": "MIT",
  "devDependencies": {
    "@types/jest": "^25.2.1",
    "@types/node-fetch": "^2.5.7",
    "jest": "^25.5.3",
    "ts-jest": "^25.4.0",
    "ts-node": "^8.9.1",
    "typescript": "^3.8.3"
  },
  "dependencies": {
    "node-fetch": "^2.6.0"
  },
  "scripts": {
    "test": "jest"
  }
}