chromium/third_party/blink/web_tests/external/wpt/html/interaction/focus/processing-model/preventScroll.html

<!doctype html>
<title>focus(options) - preventScroll</title>
<script src=/resources/testharness.js></script>
<script src=/resources/testharnessreport.js></script>
<style>
#iframe { width: 500px; height: 500px; border: none }
</style>
<iframe id=iframe src="support/preventScroll-helper.html"></iframe>
<script>
function isEntirelyInView(elm, win) {
  const inViewHorizontal = (elm.offsetLeft >= win.scrollX) &&
                           ((elm.offsetLeft + elm.clientWidth) <= (win.scrollX + win.innerWidth));
  const inViewVertical = (elm.offsetTop >= win.scrollY) &&
                         ((elm.offsetTop + elm.clientHeight) <= (win.scrollY + win.innerHeight));
  return inViewHorizontal && inViewVertical;
}

setup({explicit_done: true});

function resetState(win) {
  win.scrollTo(0, 0);
  win.document.activeElement.blur();
}

onload = () => {
  const win = document.getElementById('iframe').contentWindow;
  const elm = win.document.getElementById('button');

  test(() => {
    assert_false(isEntirelyInView(elm, win), 'initial state');
    elm.scrollIntoView();
    assert_true(isEntirelyInView(elm, win), 'after elm.scrollIntoView()');
    resetState(win);
    assert_false(isEntirelyInView(elm, win), 'after resetScrollPosition(win)');
  }, 'Sanity test');

  test(() => {
    resetState(win);
    elm.focus();
    assert_true(isEntirelyInView(elm, win));
  }, 'elm.focus() without arguments');

  test(() => {
    resetState(win);
    elm.focus(undefined);
    assert_true(isEntirelyInView(elm, win));
  }, 'elm.focus(undefined)');

  test(() => {
    resetState(win);
    elm.focus(null);
    assert_true(isEntirelyInView(elm, win));
  }, 'elm.focus(null)');

  test(() => {
    resetState(win);
    elm.focus({});
    assert_true(isEntirelyInView(elm, win));
  }, 'elm.focus({})');

  test(() => {
    resetState(win);
    elm.focus({preventScroll: false});
    assert_true(isEntirelyInView(elm, win));
  }, 'elm.focus({preventScroll: false})');

  test(() => {
    resetState(win);
    elm.focus({preventScroll: true});
    assert_equals(win.scrollX, 0);
    assert_equals(win.scrollY, 0);
  }, 'elm.focus({preventScroll: true})');

  done();
}
</script>