jest.init.js

import "regenerator-runtime/runtime";
import ReactDOM from "react-dom";

ReactDOM.createPortal = node => node;
const { testing } = process.env;
const TESTING_STORYBOOK = testing === "storybook";

if (TESTING_STORYBOOK) {
  jest.mock("react-transition-group", () => {
    const FakeTransition = jest.fn(({ children }) => children);
    const FakeCSSTransition = jest.fn(props => (props.in ? <FakeTransition>{props.children}</FakeTransition> : null));
    return { CSSTransition: FakeCSSTransition, Transition: FakeTransition, SwitchTransition: FakeTransition };
  });
}

const error = console.error;
console.error = function(warning) {
  if (
    /(Invalid prop|Failed prop type)/.test(warning) &&
    !warning.includes("of value `not valid`") &&
    !warning.includes("`ForwardRef`.")
  ) {
    throw new Error(warning);
  }
  error.apply(console, arguments);
};