Elisp: Automated Switching Between Clojure Test and Source Files

 The majority of the work that I do in emacs is Clojure programming. The Clojure navigation support (M-.) is usually all I need, but one thing that I find myself doing manually fairly often is jumping between tests and source. After suffering manual navigation for a few days, I finally automated the task using the Elisp from this blog entry.

All of my Clojure projects use both Leiningen and expectations; therefore, my directory structures always look similar to what you see below.

source - /Users/jfields/src/project-name/src/clojure/ tests - /Users/jfields/src/project-name/test/clojure/expectations/

Since my projects follow this convention, I'm able to make several assumptions about where the expectations and where the source will actually live. If you don't use expectations, or you follow a slightly different directory structure, you'll want to hack this a bit to follow your conventions.

If you're in a source file, find (and open) the expectations.

(defun test-full-path (project-root test-home)
  (concat
   (replace-regexp-in-string
    (concat (expand-file-name project-root) "src/clojure")
    (concat project-root test-home)
    (file-name-sans-extension (buffer-file-name)))
   "_expectations.clj"))

(defun find-expectations ()
  (interactive)
  (let* ((project-root (locate-dominating-file
                         (file-name-directory (buffer-file-name)) "project.clj")))
    (if project-root
        (let* ((full-path-with-clojure (test-full-path project-root
                                                       "test/clojure/expectations")))
          (if (file-exists-p full-path-with-clojure)
              (set-window-buffer (next-window) (find-file-noselect full-path-with-clojure))
            (message (concat "cound not find " full-path-with-clojure))))
      (message (concat "no project.clj found at or below " (buffer-file-name))))))

If you're in a test file, find (and open) the source.

(defun src-full-path (project-root file-name)
  (concat
   (replace-regexp-in-string
    (concat (expand-file-name project-root) "test/clojure/expectations")
    (concat project-root "src/clojure")
    (file-name-directory file-name))
   (replace-regexp-in-string
    "_expectations"
    ""
    (file-name-nondirectory file-name))))

(defun find-src ()
  (interactive)
  (let* ((project-root (locate-dominating-file
                         (file-name-directory (buffer-file-name)) "project.clj")))
    (if project-root
        (let* ((full-path (src-full-path project-root (buffer-file-name))))
          (if (file-exists-p full-path)
              (set-window-buffer (next-window) (find-file-noselect full-path))
            (message (concat "cound not find " full-path))))
      (message (concat "no project.clj found at or below " (buffer-file-name))))))