Why isn't my hook_theme being called or rendering output?
I had to add a path to my function, then it worked.

template.php

function my_name_theme($existing, $type, $theme, $path) {
    return array(
        'testy' =&gt; array(
            'variables' =&gt; array('title' =&gt; NULL),
            'template'  =&gt; 'testy',
            'path'      =&gt; drupal_get_path('theme', 'my_name') . '/templates',
        ),
    );
}