wheelevent-in-scrolling-div.html | Explore in Territory

<!DOCTYPE html>
<script src="../../../resources/testharness.js"></script>
<script src="../../../resources/testharnessreport.js"></script>
<script src="../../../resources/gesture-util.js"></script>
<script src="../../../resources/percent-based-util.js"></script>
  <div id="overflow" style="border:2px solid black;overflow:auto;height:200px;width:200px;">
    <div style="background-color:red;height:200px;width:400px;"></div>
    <div style="background-color:green;height:200px;width:400px;"></div>
    <div style="background-color:red;height:200px;width:400px;"></div>
  </div>
  <div id="console"></div>
<script>
  const overflowElement = document.getElementById("overflow");
  overflowElement.addEventListener("mousewheel", mousewheelHandler, false);

  // scroll diagonally for 1 tick.
  const SCROLL_AMOUNT = pixelsPerTick();
  const EXPECTED_DELTA = isPercentBasedScrollingEnabled() ?
    WHEEL_DELTA : SCROLL_AMOUNT;

  const { x: expectedScrollLeft, y: expectedScrollTop } = (
    calculateExpectedScroll(overflowElement, SCROLL_AMOUNT, SCROLL_AMOUNT)
  );

  let eventHandlerResolve;
  eventHandlerPromise = new Promise(function(resolve) {
      eventHandlerResolve = resolve;
  });

  promise_test (async () => {
    const x = overflowElement.offsetLeft + 5;
    const y = overflowElement.offsetTop + 5
    await mouseMoveTo(x, y);
    await gestureScroll(() => {
      return smoothScroll(SCROLL_AMOUNT, x, y, GestureSourceType.MOUSE_INPUT,
        "downright", SPEED_INSTANT, !isPercentBasedScrollingEnabled());
    }, overflowElement);

    assert_approx_equals(overflowElement.scrollTop, expectedScrollTop, 0.001);
    assert_approx_equals(overflowElement.scrollLeft, expectedScrollLeft, 0.001);
    // The test will timeout if the event handler doesn't resolve this promise.
    await eventHandlerPromise;
  });

  function mousewheelHandler(e) {
    // e.wheelDeltaX/Y is equal to number of ticks * 120. See kTickMultiplier
    // in src/third_party/blink/renderer/core/events/wheel_event.h
    if (e.deltaY == EXPECTED_DELTA && e.deltaX == EXPECTED_DELTA
        && e.wheelDeltaY == -LEGACY_MOUSE_WHEEL_TICK_MULTIPLIER
        && e.wheelDeltaX == -LEGACY_MOUSE_WHEEL_TICK_MULTIPLIER
        && e.wheelDelta == -LEGACY_MOUSE_WHEEL_TICK_MULTIPLIER
    ) {
      eventHandlerResolve();
    }
  }
</script>
chromium/third_party/blink/web_tests/fast/events/wheel/wheelevent-in-scrolling-div.html
