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.
expectTextNode(e.childNodes[4], ' ');
          } else {
            expect(e.childNodes.length).toBe(3);
            expectTextNode(e.childNodes[0], ' ');
            expectTextNode(e.childNodes[1], ' ');
            expectTextNode(e.childNodes[2], ' ');
          }
        } else {
          
          
          expect(e.childNodes.length).toBe(9);
          expectTextNode(e.childNodes[0], ' ');
          expectTextNode(e.childNodes[3], ' ');
          expectTextNode(e.childNodes[6], ' ');
        }
      });
      itRenders('a div with text sibling to a node', async render => {
        const e = await render(<div>Text<span>More Text</span></div>);
        let spanNode;
        if (ReactDOMFeatureFlags.useFiber) {
          
          
          expect(e.childNodes.length).toBe(2);
          spanNode = e.childNodes[1];
        } else {
          
          
          expect(e.childNodes.length).toBe(4);
          spanNode = e.childNodes[3];
        }