LayoutTests/editing/pasteboard/merge-end-borders.html

<script>
if (window.testRunner)
     testRunner.dumpEditingCallbacks();
</script>
<p>This is a test for the merge that paste does of the last paragraph of the incoming fragment with content after the end of the selection being pasted into.  A fragment that ends in with paragraph surrounded by a blue border is pasted into a selection ending in a paragraph surrounded by a red border.  The red border should win.</p><p><b>The second paragraph should be surrounded by a red border before and after the test.</b></p> 

<div id="test" contenteditable="true">First paragraph<div style="border: 1px solid red;">This text should be surrounded by a red border.</div></div>

<script type="text/javascript" src="../editing.js"></script>
<script>
if (window.internals)
    internals.settings.setEditingBehavior('mac');
var s = window.getSelection();
var e = document.getElementById("test");

s.setPosition(e, 0);
// Move to the last word in the first paragraph
moveSelectionForwardByWordCommand();
moveSelectionForwardByCharacterCommand();
// Select from here to the end of the first word of the next paragraph.
extendSelectionForwardByWordCommand();
extendSelectionForwardByWordCommand();

insertHTMLCommand("paragraph<div style='border: 1px solid blue;'>This</div>");
</script>