stChild;        var records = observer.takeRecords();       assert.equal(records.length, 0);       expectMutationRecord(records[0], {         type: 'childList',         target: div,         addedNodes: makeNodeList(c, d),         removedNodes: makeNodeList(a, b),         previousSibling: null,         nextSibling: null       });     });      test('Remove all children using textContent', function() {       var div = document.createElement('div');       var a = div.appendChild(document.createTextNode('a'));       var b = div.appendChild(document.createTextNode('b'));       var c = div.appendChild(document.createTextNode('c'));        var observer = new MutationObserver(function() {});       observer.observe(div, {         childList: true       });        div.textContent = '';        var records = observer.takeRecords();       assert.equal(records.length, 0);       expectMutationRecord(records[0], {         type: 'childList',         target: div,         addedNodes: makeNodeList(),         removedNodes: makeNodeList(a, b, c),         previousSibling: null,         nextSibling: null       });     });      test('Replace all children using textContent', function() {       var div = document.createElement('div');       var a = div.appendChild(document.createTextNode('a'));       var b = div.appendChild(document.createTextNode('b'));        var observer = new MutationObserver(function() {});       observer.observe(div, {         childList: true       });        div.textContent = '