<!--
  Note: if the issue is about documentation or the website, please file it at:
  https://github.com/reactjs/reactjs.org/issues/new
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**Do you want to request a *feature* or report a *bug*?**

bug.

**What is the current behavior?**

```js
  renderer.create(
    <Fragment>
      <Fragment>foo</Fragment>
    </Fragment>
  )
  .toTree()
```

> Invariant Violation: toTree() does not yet know how to handle nodes with tag=10

https://codesandbox.io/s/olky92m01y

**What is the expected behavior?**

returns a tree.

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

16.2.0

}
      componentDidCatch() {
        this.setState({error: true});
      }
    }
    const renderer = ReactTestRenderer.create(<Boundary />);
    expect(renderer.toJSON()).toEqual({
      type: 'div',
      props: {},
      children: ['Happy Birthday!'],
    });
    expect(log).toEqual([
      'Boundary render',
      'Angry render',
      'Boundary componentDidMount',
      'Boundary render',
    ]);
  });
  it('can update text nodes', () => {
    class Component extends React.Component {
      render() {
        return <div>{this.props.children}</div>;
      }
    }
    const renderer = ReactTestRenderer.create(<Component>Hi</Component>);
    expect(renderer.toJSON()).toEqual({
      type: 'div',
      children: ['Hi'],