get_page_by_path,get_page_by_title for posts

It looks like these two functions are not working for posts…

Code:

function test(){
$pid = 645;   //any valid post id
$post1 = get_post($pid);  //the post content is valid
$post = get_page_by_path($post1->post_name,OBJECT,$post1->post_type);
if ($post == null) return "not found, name:".$post1->post_name." Title:".$post1->post_title;
else return $post->post_content;
}

same if you try with get_page_by_title,
$post = get_page_by_title($post1->post_title,OBJECT,$post1->post_type);

using the same for pages works like charm.