<!DOCTYPE html>
<meta name="viewport" content="width=device-width,initial-scale=1">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="./resources/intersection-observer-test-utils.js"></script>

<style>
body {
  margin: 0;
}
#root {
  width: 200px;
  height: 200px;
  overflow: hidden;
  border-left: 50px solid yellow;
  writing-mode: vertical-rl;
}
#target {
  width: 100px;
  height: 100px;
  background-color: green;
}
</style>

<div id="root">
  <div id="target" style="width: 100px; height: 100px; transform: translateX(101px)"></div>
</div>

<script>
var entries = [];

runTestCycle(function() {
  var root = document.getElementById('root');
  var target = document.getElementById('target');
  var observer = new IntersectionObserver(function(changes) {
    entries = entries.concat(changes);
  }, { root: root });
  observer.observe(target);
  entries = entries.concat(observer.takeRecords());
  assert_equals(entries.length, 0, "No initial notifications.");
  runTestCycle(step0, "First rAF.");
}, "IntersectionObserver vertical-rl root.");

function step0() {
  runTestCycle(step1, "Set transform=translateX(50px) on target.");
  checkLastEntry(entries, 0, [251, 351, 0, 100, 0, 0, 0, 0, 50, 250, 0, 200, false]);
  target.style.transform = "translateX(50px)";
}

function step1() {
  checkLastEntry(entries, 1, [200, 300, 0, 100, 200, 250, 0, 100, 50, 250, 0, 200, true]);
}
</script>