**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.

var options = {
    entries: entries,
    debug: config.debug, 
    standalone: config.standalone, 
  };
  var bundle = browserify(options);
  config.transforms.forEach(function(transform) {
    bundle.transform({}, transform);
  });
  config.globalTransforms.forEach(function(transform) {
    bundle.transform({global: true}, transform);
  });
  config.plugins.forEach(bundle.plugin, bundle);
  
  var _this = this;
  bundle.bundle(function(err, buf) {
    if (err) {
      grunt.log.error(err);
      return done();
    }
    var src = buf.toString();
    config.after.forEach(function(fn) {
      src = fn.call(_this, src);
    });
    grunt.file.write(config.outfile, src);
    done();
  });
};