Selecting all checked checkbox return all checkbox instead using JQuery

Here is my code jsfiddle

JS file

$( document ).ready(function() {

    $(".test").children().filter(function(index, elem){
      console.log($(elem).children(":checked"));
    });

})

HTML

 <ul class="test">
 <li><input type="checkbox" name="1"><label>something</label></li>
 <li><input type="checkbox" name="2"><label>something</label></li>
 <li><input type="checkbox" name="3"><label>something</label></li>
 <li><input type="checkbox" name="4" checked><label>something</label></li>
 </ul>

I am trying to select all checked checkbox, but if I filtered by :checked I get all checkbox instead.

What am I doing wrong?