The error event on `<source>` elements doesn't work. Looking at #4370, it seems like there is an `onError` for `<video>` but I can't tell if that's supposed to work for `<source>` too.

The error event is useful so I can deduce which format the browser is using.

return str.replace(/\(at .+?:\d+\)/g, '(at **)');
  }
  beforeEach(function() {
    jest.resetModuleRegistry();
    React = require('React');
    ReactDOM = require('ReactDOM');
    ReactDOMFeatureFlags = require('ReactDOMFeatureFlags');
    ReactDOMServer = require('ReactDOMServer');
    inputValueTracking = require('inputValueTracking');
  });
  describe('updateDOM', function() {
    var ReactTestUtils;
    beforeEach(function() {
      ReactTestUtils = require('ReactTestUtils');
    });
    it('should handle className', function() {
      var container = document.createElement('div');
      ReactDOM.render(<div style={{}} />, container);
      ReactDOM.render(<div className={'foo'} />, container);
      expect(container.firstChild.className).toEqual('foo');
      ReactDOM.render(<div className={'bar'} />, container);
      expect(container.firstChild.className).toEqual('bar');
      ReactDOM.render(<div className={null} />, container);
      expect(container.firstChild.className).toEqual('');
    });
    it('should gracefully handle various style value types', function() {
      var container = document.createElement('div');
      ReactDOM.render(<div style={{}} />, container);
      var stubStyle = container.firstChild.style;