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.
expect(e.childNodes.length).toBe(3);
          expectTextNode(e.childNodes[0], 'foo');
        }
      });
      itRenders('only null and false children as blank', async render => {
        const e = await render(<div>{false}{null}{null}{false}</div>);
        expect(e.childNodes.length).toBe(0);
      });
    });
    describe('elements with implicit namespaces', function() {
      itRenders('an svg element', async render => {
        const e = await render(<svg />);
        expect(e.childNodes.length).toBe(0);
        expect(e.tagName).toBe('svg');
        expect(e.namespaceURI).toBe('http:www.w3.org/2000/svg');
      });
      itRenders('svg element with an xlink', async render => {
        let e = await render(
          <svg><image xlinkHref="http:i.imgur.com/w7GCRPb.png" /></svg>,
        );
        e = e.firstChild;
        expect(e.childNodes.length).toBe(0);
        expect(e.tagName).toBe('image');
        expect(e.namespaceURI).toBe('http:www.w3.org/2000/svg');
        expect(e.getAttributeNS('http:www.w3.org/1999/xlink', 'href')).toBe(
          'http:i.imgur.com/w7GCRPb.png',
        );
      });
      itRenders('a math element', async render => {