event.nativeEvent missing attributes after fireEvent

[mattharrigan]

• react-testing-library version: 6.0.4
• react version: 16.8.2
• node version: 10.14.1
• npm version: 6.8.0

Relevant code or config:

App.js

import React, { Component } from "react";

class App extends Component {
  state = {
    x: null,
    y: null
  };

  handleMouseDown({ nativeEvent }) {
    console.log("nativeEvent", nativeEvent);
    this.setState({ x: nativeEvent.offsetX, y: nativeEvent.offsetY });
  }

  render() {
    return (
      <div>
        <svg width="400" height="400">
          <rect
            x={0}
            y={0}
            width={400}
            height={400}
            fill="rgb(0,0,255)"
            onMouseDown={evt => this.handleMouseDown(evt)}
            data-testid="rect"
          />
        </svg>
        <span data-testid="message">
          ({this.state.x},{this.state.y})
        </span>
      </div>
    );
  }
}

export default App;

App.test.js

import React from "react";
import { render, fireEvent, prettyDOM } from "react-testing-library";
import "jest-dom/extend-expect";
import "react-testing-library/cleanup-after-each";
import App from './App'


test('first test', () => {
  const { container, getByTestId } = render(<App />);
  const rect = getByTestId('rect')
  fireEvent.mouseDown(rect, { offsetX: 10, offsetY: 20, button: 0 });
  console.log(prettyDOM(container))
  const text = getByTestId('message')
  console.log(prettyDOM(text))
  expect(getByTestId('message')).toHaveTextContent('(10,20)')
})

What you did:

Test a react component which has event handlers for mouse events

What happened:

Test failed. console.log indicates that the event does not contain a nativeEvent similar to what is present when running in the browser (chrome 73.0.3683.86)

Reproduction:

https://codesandbox.io/s/61ol4lxnvk

Problem description:

console.log from App.handleMouseDown is different when testing vs running in the browser

Suggested solution:

Unknown

Not sure if this is a bug or something I am doing incorrectly. If the second, an example in the docs might be a good addition. Thank you