Run the [`fixtures/ssr` test harness](https://github.com/facebook/react/tree/master/fixtures/ssr). In the terminal, the following warning is logged:

```
Warning: Unknown prop `onClick` on <a> tag. Remove this prop from the element. For details, see https://fb.me/react-unknown-prop
  in a (at Page.js:12)
  in p (at Page.js:18)
  in div (at Page.js:17)
  in Page (at App.js:12)
  in div (at App.js:10)
  in body (at Chrome.js:17)
  in html (at Chrome.js:9)
  in Chrome (at App.js:9)
  in App (at render.js:18)
```

SSR behavior should match client-side behavior and not warn for a valid attribute.
getChildContext() {
            return {text: this.state.text};
          }
          componentWillMount() {
            this.setState({text: 'foo'});
          }
          render() {
            return <Child />;
          }
        }
        WillMountContext.childContextTypes = {text: PropTypes.string};
        const Child = (props, context) => {
          return <div>{context.text}</div>;
        };
        Child.contextTypes = {text: PropTypes.string};
        const e = await render(<WillMountContext />);
        expect(e.textContent).toBe('foo');
      },
    );
    itThrowsWhenRendering(
      'if getChildContext exists without childContextTypes',
      render => {
        class Component extends React.Component {