jest-webpacker-setup

package.json

{
  "scripts": {
    "test": "NODE_PATH='./app/javascript/node_modules:./app/javascript' jest",
    "test:watch": "yarn test --watch",
    "test:coverage": "test --coverage"
  },
  "jest": {
    "roots": [
      "./app/javascript"
    ],
    "setupFiles": [
      "./app/javascript/packs/__test__/shim.js",
      "./app/javascript/packs/__test__/setup.js"
    ],
    "setupTestFrameworkScriptFile": "./node_modules/jest-enzyme/lib/index.js"
  }
}

setup.js

import Enzyme from 'enzyme';
import Adapter from 'enzyme-adapter-react-16';

Enzyme.configure({ adapter: new Adapter() });

const localStorageMock = {
  getItem: jest.fn(),
  setItem: jest.fn(),
  clear: jest.fn()
};
global.localStorage = localStorageMock;
jest.resetAllMocks();
jest.restoreAllMocks();

shim.js

global.requestAnimationFrame = (callback) => {
  setTimeout(callback, 0);
};