old_contents: 'use strict';
  
  var RootComponent = require('../lib/root-component.jsx'),
  
      React = require('react'),
      ReactTestUtils = require('react/lib/ReactTestUtils'),
  
      expect = require('chai').expect;
  
  function randomInt(min, max) {
      return Math.floor(Math.random() * (max - min)) + min;
  }
  
  function generateDummyItems(number) {
      var items = [],
          index;
  
      for (index = 0; index < number; index += 1) {
          items.push({
              name: '' + randomInt(10, 50)
          });
      }
  
      return items;
  }
  
  describe('Root Component', function () {
      var rootElement;
  
      beforeEach(function () {
          rootElement = React.createElement(RootComponent, {
              users: []
          });
      });
  
      it('should be a unordered list', function () {
          var renderedRootElement = ReactTestUtils.renderIntoDocument(rootElement),
              renderedDOMNode = renderedRootElement.getDOMNode();
  
          expect(renderedDOMNode.tagName).to.equal('UL');
      });
  
      describe('when the list is rendered with a set of users', function () {
          var rootElementWithItems,
              renderedElementWithItems,
              listItems,
              expectedNumberOfItems,
              dummyUsers;
  
          beforeEach(function () {
              expectedNumberOfItems = randomInt(20, 30);
              dummyUsers = generateDummyItems(expectedNumberOfItems);
  
              rootElementWithItems = React.createElement(RootComponent, {
                  users: dummyUsers
              });
  
              renderedElementWithItems = ReactTestUtils.renderIntoDocument(rootElementWithItems);
              listItems = ReactTestUtils.scryRenderedDOMComponentsWithTag(renderedElementWithItems, 'LI');
          });
  
          it('should render an LI for each of the items', function () {
              expect(listItems).to.have.length(expectedNumberOfItems);
          });
  
          it('should include the name of the user in each item', function () {
              listItems.forEach(function (listItemElement, index) {
                  var listItemNode = listItemElement.getDOMNode(),
                      dummyUser = dummyUsers[index].name;
  
                  expect(listItemNode.textContent).to.equal(dummyUser);
              });
          });
      });
  });
  
new_contents: 'use strict';
  
  var RootComponent = require('../lib/root-component.jsx'),
  
      React = require('react'),
      ReactTestUtils = require('react/lib/ReactTestUtils'),
  
      expect = require('chai').expect;
  
  function randomInt(min, max) {
      return Math.floor(Math.random() * (max - min)) + min;
  }
  
  function generateDummyItems(number) {
      var items = [],
          index;
  
      for (index = 0; index < number; index += 1) {
          items.push({
              name: '' + randomInt(10, 50)
          });
      }
  
      return items;
  }
  
  describe('Root Component', function () {
      var rootElement;
  
      beforeEach(function () {
          rootElement = React.createElement(RootComponent, {
              users: []
          });
      });
  
      it('should be a unordered list', function () {
          var renderedRootElement = ReactTestUtils.renderIntoDocument(rootElement),
              renderedDOMNode = React.findDOMNode(renderedRootElement);
  
          expect(renderedDOMNode.tagName).to.equal('UL');
      });
  
      describe('when the list is rendered with a set of users', function () {
          var rootElementWithItems,
              renderedElementWithItems,
              listItems,
              expectedNumberOfItems,
              dummyUsers;
  
          beforeEach(function () {
              expectedNumberOfItems = randomInt(20, 30);
              dummyUsers = generateDummyItems(expectedNumberOfItems);
  
              rootElementWithItems = React.createElement(RootComponent, {
                  users: dummyUsers
              });
  
              renderedElementWithItems = ReactTestUtils.renderIntoDocument(rootElementWithItems);
              listItems = ReactTestUtils.scryRenderedDOMComponentsWithTag(renderedElementWithItems, 'LI');
          });
  
          it('should render an LI for each of the items', function () {
              expect(listItems).to.have.length(expectedNumberOfItems);
          });
  
          it('should include the name of the user in each item', function () {
              listItems.forEach(function (listItemElement, index) {
                  var listItemNode = React.findDOMNode(listItemElement),
                      dummyUser = dummyUsers[index].name;
  
                  expect(listItemNode.textContent).to.equal(dummyUser);
              });
          });
      });
  });
  
subject: Replace `getDOMNode` with `React.findDOMNode`. Thanks to @dariocravero for pointing that out.