<!doctype html>
<title>Visual Viewport Resize Event Order</title>
<meta charset=utf-8>
<link rel="help" href="https://wicg.github.io/visual-viewport/index.html">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="/resources/testdriver.js"></script>
<script src="/resources/testdriver-vendor.js"></script>
<style>
  iframe {
    width: 300px;
    height: 300px;
  }
</style>

<body>
  <iframe srcdoc="<!DOCTYPE html>"></iframe>
</body>

<script>

async function oneRaf(win) {
  return new Promise((resolve) => {
    win.requestAnimationFrame(resolve);
  });
}

// Runs the test on the given window object, asserts that event handlers on the
// DOMWindow object are fired before those on the VisualViewport object.
// `resizeFunc` is used to perform the resize.
async function runTest(win, resizeFunc) {
  const resize_events = [];

  win.onresize = () => { resize_events.push('window-attribute'); }
  win.addEventListener('resize', () => { resize_events.push('window-addEventListener'); });
  win.visualViewport.onresize = () => { resize_events.push('visualViewport-attribute'); }
  win.visualViewport.addEventListener('resize', () => {
        resize_events.push('visualViewport-addEventListener'); });

  assert_equals(resize_events.toString(), '', 'PRECONDITION');
  resizeFunc(500, 600);

  await oneRaf(win);

  assert_equals(resize_events.toString(),
                'window-attribute,window-addEventListener,' +
                'visualViewport-attribute,visualViewport-addEventListener');
}

onload = () => {
  // Test the event order in a top-level window which we will programmatically
  // resize.
  promise_test(async t => {
    let popup = null;
    test_driver.bless('Open a popup in a new window', () => {
        popup = window.open('about:blank', 'newwindow', 'width=300,height=300');
    });
    await t.step_wait(() => popup != null, "Opened popup window");

    await runTest(popup, (x, y) => {popup.resizeTo(x, y);});
  }, 'Popup: DOMWindow resize fired before VisualViewport.');

  // Also test the resize resulting from an iframe's size change.
  promise_test(async t => {
    const iframe = frames[0];
    await runTest(iframe, (x, y) => {iframe.frameElement.style.width = x + 'px';
                                     iframe.frameElement.style.height = y + 'px';
                                     iframe.frameElement.offsetWidth; /* force reflow */});
  }, 'iframe: DOMWindow resize fired before VisualViewport.');
}

</script>
