resize-observer/eventloop.html

<!doctype html>
<title>ResizeObserver notification event loop tests</title>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="./resources/resizeTestHelper.js"></script>
<div id="log"></div>
<script>
'use strict';

// allow uncaught exception because ResizeObserver posts exceptions
// to window error handler when limit is exceeded.
// This codepath is tested in this file.

setup({allow_uncaught_exception: true});

function template() {
  let helper = new ResizeTestHelper(
    "test0: title",
  [
    {
      setup: observer => {
      },
      notify: (entries, observer) => {
        return true;  // Delay next step
      }
    }
  ]);
  return helper.start();
}

var onErrorCalled = false;

window.onerror = err => {
  onErrorCalled = true;
}

function test0() {
  let t1 = createAndAppendElement("div");
  let t2 = createAndAppendElement("div", t1);
  let t3 = createAndAppendElement("div", t2);

  let divs = [t1, t2, t3];
  let rAF = 0;
  let helper = new ResizeTestHelper(
    "test0: multiple notifications inside same event loop",
  [
    {
      setup: observer => {
        onErrorCalled = false;
        observer.observe(t1);
        observer.observe(t2);
        observer.observe(t3);
      },
      notify: (entries, observer) => {
        assert_equals(entries.length, 3, "3 notifications");
      }
    },
    {
      setup: observer => {
        helper.startCountingRaf();
        divs.forEach( el => { el.style.width = "101px";});
      },
      notify: (entries, observer) => {
        // t1 is not delivered
        assert_equals(entries.length, 2, "2 notifications");
        assert_equals(helper.rafCount, 0, "still in same loop");
      }
    },
    {
      setup: observer => {
        divs.forEach( el => { el.style.width = "102px";});
      },
      notify: (entries, observer) => {
        assert_equals(entries.length, 1, "1 notifications");
        assert_equals(helper.rafCount, 0, "same loop");
      }
    },
    { // t1 and t2 get notified
      setup: observer => {
      },
      notify: (entries, observer) => {
        assert_equals(entries.length, 2, "2 notifications");
        assert_equals(helper.rafCount, 1, "new loop");
        assert_equals(onErrorCalled, true, "error was fired");
        observer.disconnect();
      }
    }
  ]);

  return new Promise((resolve, reject) => {
    // This test uses requestAnimationFrame() to check the count of event loop,
    // but on some browsers, the FrameRequestCallback may be throttled (i.e.
    // simply fired after some extra time) in cases where this test is running
    // in an iframe that hasn't yet been painted (i.e. we're not visible).
    // This may result in some intermittent failures if this test didn't get a
    // first paint (and hence may not have started firing FrameRequestCallbacks)
    // by the time the test starts expecting helper.rafCount to have changed.
    //
    // Therefore, we don't start the test logic until body.onload has fired.
    // This increases the likelihood that this testcase will have gotten a
    // chance to paint when we start invoking requestAnimationFrame, and that
    // its rAF callbacks will fire when the test logic expects them to.
    document.body.onload = () => resolve();
  }).then(() => {
    return helper.start(() => t1.remove());
  });
}

function test1() {
  let t1 = createAndAppendElement("div");
  t1.style.width = '100px';
  let t2 = createAndAppendElement("div", t1);
  let t3 = createAndAppendElement("div", t2);
  let shadow = t3.attachShadow({ mode: "open" });
  let t4 = createAndAppendElement("div", shadow);
  let t5 = createAndAppendElement("div", t4);

  let resizers = [t1, t2, t3, t4, t5];

  // Testing depths of shadow roots
  // DOM: t1 <- t2 <- t3 <-shadow- t4 <- t5
  let helper = new ResizeTestHelper(
    "test1: depths of shadow roots",
  [
    {
      setup: observer => {
        onErrorCalled = false;
        resizers.forEach( el => observer.observe(el) );
      },
      notify: (entries, observer) => {
        assert_equals(entries.length, 5, "all entries resized");
      }
    },
    {
      setup: observer => {
        resizers.forEach( el => el.style.width = "111px" );
      },
      notify: (entries, observer) => {
        assert_equals(entries.length, 4, "depth limited");
      }
    },
    {
      setup: observer => {
        resizers.forEach( el => el.style.width = "112px" );
      },
      notify: (entries, observer) => {
        assert_equals(entries.length, 3, "depth limited");
      }
    },
    {
      setup: observer => {
        resizers.forEach( el => el.style.width = "113px" );
      },
      notify: (entries, observer) => {
        assert_equals(entries.length, 2, "depth limited");
      }
    },
    {
      setup: observer => {
        resizers.forEach( el => el.style.width = "114px" );
      },
      notify: (entries, observer) => {
        assert_equals(entries.length, 1, "depth limited");
      }
    },
    {
      setup: observer => {
      },
      notify: (entries, observer) => {
        assert_equals(entries.length, 4, "limit notifications");
        assert_equals(onErrorCalled, true, "breached limit");
        observer.disconnect();
      }
    },
  ]);
  return helper.start(() => t1.remove());
}

function test2() {
  // <div id="container">
  //   <div id="a1" style="width:100px;height:100px">
  //     <div id="a2" style="width:100px;height:100px"></div>
  //   </div>
  //   <div id="b1" style="width:100px;height:100px">
  //     <div id="b2" style="width:100px;height:100px"></div>
  //   </div>
  // </div>
  let container = createAndAppendElement("div");
  let a1 = createAndAppendElement("div", container);
  let a2 = createAndAppendElement("div", a1);
  let b1 = createAndAppendElement("div", container);
  let b2 = createAndAppendElement("div", b1);
  let targets = [a1, a2, b1, b2];

  let helper = new ResizeTestHelper(
    "test2: move target in dom while inside event loop",
  [
    {
      setup: observer => {
        for (let t of targets)
          observer.observe(t);
      },
      notify: (entries, observer) => {
        return true;  // delay next observation
      }
    },
    { // resize them all
      setup: observer => {
        for (let t of targets)
          t.style.width = "110px";
      },
      notify: (entries, observer) => {
        assert_equals(entries.length, targets.length, "all targets observed");
      }
    },
    { // resize all, move dom upwards
      setup: observer => {
        for (let t of targets)
          t.style.width = "130px";
        container.appendChild(b2);
      },
      notify: (entries, observer) => {
        assert_equals(entries.length, 1, "b2 moved upwards");
        assert_equals(entries[0].target, a2);
      }
    },
    { // resize all, move dom downwards
      setup: observer => {
        for (let t of targets)
          t.style.width = "130px";
        a2.appendChild(b2);
      },
      notify: (entries, observer) => {
        assert_equals(entries.length, 1, "b2 moved downwards");
        assert_equals(entries[0].target, b2);
      }
    },
  ]);
  return helper.start(() => container.remove());
}

let guard;
test(_ => {
  assert_own_property(window, "ResizeObserver");
  guard = async_test('guard');
}, "ResizeObserver implemented")

test0()
  .then(() => test1())
  .then(() => test2())
  .then(() => guard.done());

</script>