Add a helpers library

This way different modules can use it without getting weird circular
dependencies.

emacs/.emacs.d/init.org

@@ -119,31 +119,10 @@ To start off, first I need to enable lexical binding.
 
 * Helper functions
 
-  I have noticed that I refer to the combination of
-  =user-emacs-directory= and "data/" a lot, so I wrote this function
-  to make referencing it cleaner. Also useful if I ever want to move
-  my data directory.
+  I have some helper functions stored away in a separate file.
 
   #+BEGIN_SRC emacs-lisp
-    (defun oni:data-location (file-name)
-      "Return the location of FILE-NAME within my data directory.
-    This is currently the data directory under the
-    `user-emacs-directory'."
-      (concat user-emacs-directory "data/" file-name))
-  #+END_SRC
-
-  I also wrote a test for it.
-
-  #+BEGIN_SRC emacs-lisp
-    (with-eval-after-load 'ert
-      (ert-deftest oni:data-location ()
-        "Test that `oni:data-location' returns the correct locations."
-        (should (string= "~/.emacs.d/data/backup-files/"
-                         (oni:data-location "backup-files/")))
-        (should (string= "~/.emacs.d/data/auto-save-files/"
-                         (oni:data-location "auto-save-files/")))
-        (should (string= "~/.emacs.d/data/auto-save-list/.saves-"
-                         (oni:data-location "auto-save-list/.saves-")))))
+    (require 'oni-helpers)
   #+END_SRC
 
 * Backups

emacs/.emacs.d/site-lisp/oni-helpers.el

@@ -0,0 +1,44 @@
+;;; oni-helpers.el --- Helper functions for Emacs init  -*- lexical-binding: t; -*-
+
+;; Copyright (C) 2016  Tom Willemse
+
+;; Author: Tom Willemse <tom@ryuslash.org>
+;; Keywords: convenience
+
+;; This program is free software; you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation, either version 3 of the License, or
+;; (at your option) any later version.
+
+;; This program is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+;;; Commentary:
+
+;; Helpers for my Emacs init.
+
+;;; Code:
+
+(defun oni:data-location (file-name)
+  "Return the location of FILE-NAME within my data directory.
+    This is currently the data directory under the
+    `user-emacs-directory'."
+  (concat user-emacs-directory "data/" file-name))
+
+(with-eval-after-load 'ert
+  (ert-deftest oni:data-location ()
+    "Test that `oni:data-location' returns the correct locations."
+    (should (string= "~/.emacs.d/data/backup-files/"
+                     (oni:data-location "backup-files/")))
+    (should (string= "~/.emacs.d/data/auto-save-files/"
+                     (oni:data-location "auto-save-files/")))
+    (should (string= "~/.emacs.d/data/auto-save-list/.saves-"
+                     (oni:data-location "auto-save-list/.saves-")))))
+
+(provide 'oni-helpers)
+;;; oni-helpers.el ends here