LayoutTests/editing/execCommand/15381.html

<div id="test"><div id="edit" contentEditable="true">centered text</div></div>

<script>
if (window.testRunner)
    window.testRunner.dumpAsText();
    
test = document.getElementById("test");
edit = document.getElementById("edit");

window.getSelection().setPosition(edit, 0);
document.execCommand("JustifyCenter");

expected = '<div id="edit" contenteditable="true"><div style="text-align: center;">centered text</div></div>';
actual = test.innerHTML;

output = "This tests to make sure that centering content whose enclosing block is the root editable element doesn't modify the root editable element.\n\n"

if (actual == expected)
    output += "Success";
else
    output += "Failure.  Expected: " + expected + ", found: " + actual;
    
document.body.innerText = output;
</script>