**Do you want to request a _feature_ or report a _bug_?**

Report a bug.

**What is the current behavior?**

When testing components, `Warning: ReactComponentTreeDevtool: Missing React element for debugID 1 when building stack` is shown when calling `TestUtils.renderIntoDocument`.

**If the current behavior is a bug, please provide the steps to reproduce and if possible a minimal demo of the problem via https://jsfiddle.net or similar (template: https://jsfiddle.net/reactjs/69z2wepo/).**

https://github.com/angusfretwell/reproduce-debugid-warning (`npm install && npm test`).

**What is the expected behavior?**

According to #7187 this is an internal warning and shouldn't be displayed.

**Which versions of React, and which browser / OS are affected by this issue? Did this work in previous versions of React?**
- react@15.2.1
- react-addons-test-utils@15.2.1
- react-dom@15.2.1

I didn't receive this warning on 15.2.0.

'use strict';
var browserify = require('browserify');
var grunt = require('grunt');
module.exports = function() {
  var config = this.data;
  
  var done = this.async();
  
  
  
  config.transforms = config.transforms || [];
  config.globalTransforms = config.globalTransforms || [];
  config.plugins = config.plugins || [];
  config.after = config.after || [];
  
  var entries = grunt.file.expand(config.entries);