Testing jQuery.data() with undefined value

HTML

<div id="test">hi</div>

JavaScript

var testDiv = $('#test'), ret = null;
console.log('Expecting undefined: ' + testDiv.data("someData"));

ret = testDiv.data("someData", "value");
console.log('true == ' + (testDiv == ret));
console.log('Expecting "value": ' + testDiv.data("someData"));

ret = testDiv.data("someData", undefined);
console.log('true == ' + (testDiv == ret));
console.log('Expecting undefined: ' + testDiv.data("someData"));