Add test logic to make sure that events get tested when rendering on …

…top of server-generated markup. (facebook#6668)

src/renderers/dom/server/__tests__/ReactServerRendering-test.js

@@ -232,26 +232,32 @@ describe('ReactServerRendering', function() {
       ExecutionEnvironment.canUseDOM = true;
       element.innerHTML = lastMarkup;
 
-      ReactDOM.render(<TestComponent name="x" />, element);
+      var instance = ReactDOM.render(<TestComponent name="x" />, element);
       expect(mountCount).toEqual(3);
       expect(element.innerHTML).toBe(lastMarkup);
+
+      // Ensure the events system works after mount into server markup
+      expect(numClicks).toEqual(0);
+      ReactTestUtils.Simulate.click(ReactDOM.findDOMNode(instance.refs.span));
+      expect(numClicks).toEqual(1);
+
       ReactDOM.unmountComponentAtNode(element);
       expect(element.innerHTML).toEqual('');
 
       // Now simulate a situation where the app is not idempotent. React should
       // warn but do the right thing.
       element.innerHTML = lastMarkup;
       spyOn(console, 'error');
-      var instance = ReactDOM.render(<TestComponent name="y" />, element);
+      instance = ReactDOM.render(<TestComponent name="y" />, element);
       expect(mountCount).toEqual(4);
       expect(console.error.argsForCall.length).toBe(1);
       expect(element.innerHTML.length > 0).toBe(true);
       expect(element.innerHTML).not.toEqual(lastMarkup);
 
-      // Ensure the events system works
-      expect(numClicks).toEqual(0);
-      ReactTestUtils.Simulate.click(ReactDOM.findDOMNode(instance.refs.span));
+      // Ensure the events system works after markup mismatch.
       expect(numClicks).toEqual(1);
+      ReactTestUtils.Simulate.click(ReactDOM.findDOMNode(instance.refs.span));
+      expect(numClicks).toEqual(2);
     });
 
     it('should throw with silly args', function() {