is_page_template Conditional is not working!

Hallo. I struggle really hard with the is_page_template Conditional.
The problem is that when I “include” my template functions file (country_template_functions.php) into my functions.php file, the is_page_template conditional doesn’t work anymore.
If I remove the “include template…” from my functions.php it does work, but this is no solution since the file has to be included into the functions.php to make it working.

Can anyone explain me what might be wrong?
The is_page conditional works in both cases.

if (file_exists(THESIS_CUSTOM . '/country_template_functions.php')){
    include(THESIS_CUSTOM . '/country_template_functions.php');
}

function test() {
    if ( is_page_template( "country_template.php" ) ){
	echo "is page template works";
    }
}
add_action('thesis_hook_before_header','test');

I am using the Thesis Theme.