Add test for rendering over pre-rendered text nodes

src/renderers/dom/shared/__tests__/ReactDOMTextComponent-test.js

@@ -13,11 +13,13 @@
 
 var React;
 var ReactDOM;
+var ReactDOMServer;
 
 describe('ReactDOMTextComponent', function() {
   beforeEach(function() {
     React = require('React');
     ReactDOM = require('ReactDOM');
+    ReactDOMServer = require('ReactDOMServer');
   });
 
   it('updates a mounted text component in place', function() {
@@ -90,4 +92,26 @@ describe('ReactDOMTextComponent', function() {
     inst = ReactDOM.render(<div><span />{'bar'}</div>, el);
     expect(textNode.data).toBe('bar');
   });
+
+  it('are preserved in pre-rendered markup', function() {
+    var el = document.createElement('div');
+    var reactElements = <div>{'foo'}<span key={0} />{'bar'}<span key={1} />{'baz'}</div>;
+    el.innerHTML = ReactDOMServer.renderToString(reactElements);
+
+    var childNodes = el.childNodes[0].childNodes;
+    var text1 = childNodes[0];
+    var span1 = childNodes[1];
+    var text2 = childNodes[2];
+    var span2 = childNodes[3];
+    var text3 = childNodes[4];
+
+    var inst = ReactDOM.render(reactElements, el);
+    childNodes = ReactDOM.findDOMNode(inst).childNodes;
+    expect(childNodes.length).toBe(5);
+    expect(childNodes[0]).toBe(text1);
+    expect(childNodes[1]).toBe(span1);
+    expect(childNodes[2]).toBe(text2);
+    expect(childNodes[3]).toBe(span2);
+    expect(childNodes[4]).toBe(text3);
+  });
 });