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.
if (console.error.calls && console.error.calls.reset) {
    console.error.calls.reset();
  } else {
    spyOn(console, 'error');
  }
  const result = await fn();
  if (
    console.error.calls.count() !== count &&
    console.error.calls.count() !== 0
  ) {
    console.log(
      `We expected ${count} warning(s), but saw ${console.error.calls.count()} warning(s).`,
    );
    if (console.error.calls.count() > 0) {
      console.log(`We saw these warnings:`);
      for (var i = 0; i < console.error.calls.count(); i++) {
        console.log(console.error.calls.argsFor(i)[0]);
      }
    }
  }
  expectDev(console.error.calls.count()).toBe(count);
  return result;
}
function renderIntoDom(reactElement, domElement, errorCount = 0) {