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.
const UndefinedComponent = () => undefined;
        await render(<UndefinedComponent />, 1);
      });
      itThrowsWhenRendering('a number component', async render => {
        const NumberComponent = () => 54;
        await render(<NumberComponent />, 1);
      });
      itThrowsWhenRendering('null', render => render(null));
      itThrowsWhenRendering('false', render => render(false));
      itThrowsWhenRendering('undefined', render => render(undefined));
      itThrowsWhenRendering('number', render => render(30));
      itThrowsWhenRendering('string', render => render('foo'));
    });
  });
  describe('form controls', function() {
    describe('inputs', function() {
      itRenders('an input with a value and an onChange', async render => {
        const e = await render(<input value="foo" onChange={() => {}} />);
        expect(e.value).toBe('foo');
      });
      itRenders('an input with a value and readOnly', async render => {
        const e = await render(<input value="foo" readOnly={true} />);
        expect(e.value).toBe('foo');
      });
      itRenders(
        'an input with a value and no onChange/readOnly',
        async render => {
          
          
          const e = await render(<input value="foo" />, 1);