title: Testing mouse event position with react testing library
body: <p>I want to test an API which uses the mouse position to do some computations. I am using react testing library and mocha.</p>
  <p>Something like -</p>
  <pre class="lang-js prettyprint-override"><code>const searchClosestPoint(evt) = {
      const {clientX, clientY} = evt;
      // do some computations
      return result;
  }
  </code></pre>
  <pre class="lang-js prettyprint-override"><code>// In my test, assume I have some svg element
  const evt = createEvent(someSVGElement, 'mouseoever');
  fireEvent(someSVGElement, evt);
  
  expect(searchPoint(evt)).to.equal(expectedResult);
  </code></pre>
  <p>However, the clientX and clientY always seems to be 0. Any clue on how this can be done and why it may be happening?</p>
  <p>Thanks a lot!</p>