If custom field exists

I need a some kind of code snippet that will do something like this:

<?php
$test = get_post_id(post->ID, "testing", TRUE);
if($test !== '') {
echo "<div class=\"view\">Hello world</div>";
}
else
{
echo "<div class=\"notview\">Access Denied..</div>";
}
?>

But for some reason this code I wrote doesn’t work? Or is it just me using it in the wrong way?