[event-handler-processing-algorithm.html]
  type: testharness
  [beforeunload listener returning null cancels event]
    bug: https://github.com/servo/servo/issues/10787
    expected: FAIL

  [mouseover listener returning false cancels event (using Event)]
    expected: FAIL

  [mouseover listener returning false cancels event (using MouseEvent)]
    expected: FAIL

  [mouseover listener returning true doesn't cancel event (using Event)]
    expected: FAIL

  [mouseover listener returning true doesn't cancel event (using MouseEvent)]
    expected: FAIL