React-test-renderer: support for portal

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Report a bug

What is the current behavior?

This test

import React from 'react';
import { createPortal } from 'react-dom';
import renderer from 'react-test-renderer';

const Drop = () => (
  createPortal(
    <div>hello</div>,
    this.dropContainer
  )
);

test('Drop renders', () => {
  const component = renderer.create(
    <div>
      <input />
      <Drop />
    </div>
  );
  const tree = component.toJSON();
  expect(tree).toMatchSnapshot();
});

fails with

Invariant Violation: Drop(...): Nothing was returned from render. This usually means a return statement is missing. Or, to render nothing, return null.

This test passes if I wrap createPortal in a container.

<div>
  {createPortal(
    <div>hello</div>,
    this.dropContainer
  )}
</div>

What is the expected behavior?

The code without the parent container works fine in the browser. So it seems that I'm adding the parent div just for the test to pass. I believe react-test-renderer should support empty returns?

Which versions of React, and which browser / OS are affected by this issue? Did this work in previous versions of React?

Lastest

Start by reproducing the shown react-test-renderer case using createPortal, renderer.create, toJSON, and the snapshot assertion. Compare it with the wrapped-parent example; done means a portal rendered directly from the component works without the extra parent div and the snapshot test passes.