Codebase Browser
chromium
Go to App

chromium/third_party/blink/web_tests/dom/mutation-event-tests/fast/dom/MutationObserver/added-out-of-order.html 

<!DOCTYPE html>
<div id="sandbox" style="display:none"><span></span></div>
<script src="../../../../../resources/js-test.js"></script>
<script>
description("Test MutationEvents interfering with MutationObservers: adding nodes 'out of order'");
var sandbox = document.getElementById('sandbox');
var inserted = false;
sandbox.addEventListener('DOMNodeRemoved', function() {
    if (!inserted) {
        sandbox.appendChild(document.createElement('div'));
        inserted = true;
    }
});
var observer = new MutationObserver(function(){});
observer.observe(sandbox, {childList: true});
sandbox.textContent = 'hello world';

var mutations = observer.takeRecords();
shouldBe("mutations.length", "3");
shouldBe("mutations[0].addedNodes.length", "0");
shouldBe("mutations[0].removedNodes.length", "1");
shouldBe("mutations[0].removedNodes[0].tagName", "'SPAN'");
shouldBe("mutations[1].addedNodes.length", "1");
shouldBe("mutations[1].removedNodes.length", "0");
shouldBe("mutations[1].addedNodes[0].tagName", "'DIV'");
shouldBe("mutations[2].addedNodes.length", "1");
shouldBe("mutations[2].removedNodes.length", "0");
shouldBe("mutations[2].addedNodes[0].nodeValue", "'hello world'");
</script>