chromium/src/third_party/blink/web_tests/editing/pasteboard/copy-resolves-urls.html

<p>This tests to make sure that copying/pasting HTML results in URLs being full paths so
pasting between websites works.  To test manually, copy the selection and paste it into
the blue box.  If this is a file:/// url, the links should be relative.  If this is an
http:// url, the links should be absolute.</p>
<div id="test">
<a href="../relative/path/foo.html">link</a><img src="resources/abe.png">
</div>
<div id="pastehere" contenteditable="true" style="border: 1px solid blue" onpaste="paste()">
</div>
<div id="results"></div>
<script>
function test()
{
    var s = window.getSelection();
    var test = document.getElementById("test");
    s.selectAllChildren(test);

    if (!window.testRunner)
        return;
    testRunner.dumpAsText();
    testRunner.waitUntilDone();

    document.execCommand("Copy");
    var pasteHere = document.getElementById("pastehere");
    s.collapse(pasteHere, 0);
    document.execCommand("Paste");
}

function paste()
{
    setTimeout(afterPaste, 0);
}

function afterPaste()
{
    var pasteHere = document.getElementById("pastehere");
    var results = document.getElementById("results");
    results.appendChild(document.createTextNode(pasteHere.innerHTML));
    if (window.testRunner)
        testRunner.notifyDone();
}

test();
</script>