function test_delete() {
    if( !current_user_can( 'activate_plugins' ) )
        return;
    check_admin_referer( 'bulk-plugins' );

    if( __FILE__ != WP_UNINSTALL_PLUGIN )
        return;

    delete_option( 'test_option' );
}

register_uninstall_hook( __FILE__, 'test_delete' );