third_party/web_platform_tests/selection/Document-open.html

<!doctype html>
<title>Selection Document.open() tests</title>
<div id=log></div>
<script src=/resources/testharness.js></script>
<script src=/resources/testharnessreport.js></script>
<script>
"use strict";

// This tests the HTML spec requirement "Replace the Document's singleton
// objects with new instances of those objects. (This includes in particular
// the Window, Location, History, ApplicationCache, and Navigator, objects, the
// various BarProp objects, the two Storage objects, the various HTMLCollection
// objects, and objects defined by other specifications, like Selection and the
// document's UndoManager. It also includes all the Web IDL prototypes in the
// JavaScript binding, including the Document object's prototype.)" in the
// document.open() algorithm.

var iframe = document.createElement("iframe");
var t = async_test("Selection must be replaced with a new object after document.open()");
iframe.onload = function() {
    t.step(function() {
        var originalSelection = iframe.contentWindow.getSelection();
        assert_equals(originalSelection.rangeCount, 0,
            "Sanity check: rangeCount must be initially 0");
        iframe.contentDocument.body.appendChild(
            iframe.contentDocument.createTextNode("foo"));
        var range = iframe.contentDocument.createRange();
        range.selectNodeContents(iframe.contentDocument.body);
        iframe.contentWindow.getSelection().addRange(range);
        assert_equals(originalSelection.rangeCount, 1,
            "Sanity check: rangeCount must be 1 after adding a range");

        iframe.contentDocument.open();

        assert_not_equals(iframe.contentWindow.getSelection(), originalSelection,
            "After document.open(), the Selection object must no longer be the same");
        assert_equals(iframe.contentWindow.getSelection().rangeCount, 0,
            "After document.open(), rangeCount must be 0 again");
    });
    t.done();
    document.body.removeChild(iframe);
};
document.body.appendChild(iframe);
</script>