// ./src/layouts/index.js
const importAll = (r) =>
    r.keys().reduce(
        (acc, key) => ({
            ...acc,
            [key.replace(/^\.\/(.*).json$/, '$1')]: r(key)
        }),
        {}
    );

module.exports = importAll(require.context('./', true, /\.json$/));

//./src/util.js
import layouts from '../layouts';
export const getLayout(name) {
  return layouts[name];
}

//./src/util.test.js
describe('my test suite', () => {
  afterEach(() => {
     jest.clearAllMocks();
  })
  test('test number one', () => {
      jest.mock('./layouts', () => ({
          layout1 : { a : 1 },
          layout2 : { b: 2 },
     }));
     assert.equals(getLayout('layout1').a, 1);
     assert.equals(getLayout('layout2').b, 2);
  });
  test('test number two', () => {
     assert.equals(getLayout('layout1').a, 1);
     assert.equals(getLayout('layout2').b, 2);
  });
});