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  Note: if the issue is about documentation or the website, please file it at:
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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

const tree = renderer.toTree();
    cleanNodeOrArray(tree);
    expect(prettyFormat(tree)).toEqual(
      prettyFormat({
        type: 'div',
        instance: null,
        nodeType: 'host',
        props: {},
        rendered: [
          {
            type: Foo,
            nodeType: 'component',
            props: {},
            instance: null,
            rendered: [
              {
                type: 'div',
                nodeType: 'host',
                props: {},
                instance: null,
                rendered: ['One'],
              },
              {
                type: 'div',
                nodeType: 'host',
                props: {},
                instance: null,
                rendered: ['Two'],
              },
              {