Using the wordpress api from another file

I want to use the wordpress api from a php(test.php) file located outside the wordpress directory.I want to create post and create post category in the wordpress from this php(test.php) file. i want to use the following functions

• wp_insert_post
• wp_insert_category
• category_exists
• wp_set_post_tags

please give the list of files to be included to use these functions

Sree