Observed this on react@16.0.0-beta.5

```js
import React from 'react';
import { renderToString } from 'react-dom/server';

const B = () => 'b';

console.log(renderToString(<div>{'a'}<B />{'c'}</div>));
```

This renders as `<div data-reactroot="">a<!-- -->bc</div>`. If you try to hydrate this you'll get the error: Text content did not match. Server: "bc" Client: "b".
},
      );
      itRenders('badly cased SVG attribute with a warning', async render => {
        const e = await render(<text textlength="10" />, 1);
        expect(e.getAttribute('textLength')).toBe('10');
      });
      itRenders('no badly cased aliased SVG attribute alias', async render => {
        const e = await render(<text strokedasharray="10 10" />, 1);
        expect(e.hasAttribute('stroke-dasharray')).toBe(false);
        expect(e.getAttribute('strokedasharray')).toBe('10 10');
      });
      itRenders(
        'no badly cased original SVG attribute that is aliased',
        async render => {
          const e = await render(<text stroke-dasharray="10 10" />, 1);
          expect(e.getAttribute('stroke-dasharray')).toBe('10 10');
        },
      );
    });
    describe('unknown attributes', function() {
      itRenders('unknown attributes', async render => {
        const e = await render(<div foo="bar" />);
        expect(e.getAttribute('foo')).toBe('bar');
      });
      itRenders('unknown data- attributes', async render => {
        const e = await render(<div data-foo="bar" />);
        expect(e.getAttribute('data-foo')).toBe('bar');
      });
      itRenders('badly cased reserved attributes', async render => {
        const e = await render(<div CHILDREN="5" />, 1);