Programmer - Insert after parent of element

Programmer Question

What sort of selector would be I need in order to insert after the parent (divouter) of the test3 class in the example below? Thanks.

<div class='divouter'>
    <div class='divinner'>
        <input class=test1></input>
    </div>
</div>
<div class='divouter'>
    <div class='divinner'>
        <input class=test2></input>
    </div>
</div>
<div class='divouter'>
    <div class='divinner'>
        <input class=test3></input>
    </div>
</div>
<div class='divouter'>
    <div class='divinner'>
        <input class=test4></input>
    </div>
</div>