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 markup = await renderIntoStream(reactElement, errorCount);
  var domElement = document.createElement('div');
  domElement.innerHTML = markup;
  return domElement.firstChild;
}
const clientCleanRender = (element, errorCount = 0) => {
  const div = document.createElement('div');
  return renderIntoDom(element, div, errorCount);
};
const clientRenderOnServerString = async (element, errorCount = 0) => {
  const markup = await renderIntoString(element, errorCount);
  resetModules();
  var domElement = document.createElement('div');
  domElement.innerHTML = markup;
  const serverElement = domElement.firstChild;
  const clientElement = await renderIntoDom(element, domElement, errorCount);
  
  
  
  expect(serverElement === clientElement).toBe(true);
  return clientElement;
};
function BadMarkupExpected() {}