<!--
  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

root: ReactTestInstance,
  predicate: Predicate,
  options: ?FindOptions,
): Array<ReactTestInstance> {
  const deep = options ? options.deep : true;
  const results = [];
  if (predicate(root)) {
    results.push(root);
    if (!deep) {
      return results;
    }
  }
  for (const child of root.children) {
    if (typeof child === 'string') {
      continue;
    }
    results.push(...findAll(child, predicate, options));
  }
  return results;
}
function expectOne(