gistfile1.el

(defun string/starts-with (s arg)
  (cond ((>= (length s) (length arg))
	 (string-equal (substring s 0 (length arg)) arg))
	(t nil)))

(defun chomp (str)
  (while (string-match "\\`\n+\\|^\\s-+\\|\\s-+$\\|\n+\\'"
		       str)
    (setq str (replace-match "" t t str)))
  str)

;; Scan comments from the current point to the top while it finds
;; lines beginning with ';;#'.
;; Each line with ';;#' -- testcase. Remove the ';;#', split it and
;; save as a list with two values.
;; Results are accumulated in the variable 'tc'.
(defun get-test-cases (tc)
  ;; 1) Mark whole current line from the beginning to the end.
  (beginning-of-line)
  (set-mark (point))
  (end-of-line)
  ;; 2) Copy current line text (without text properties).
  (let ((line (buffer-substring-no-properties (mark) (point))))
    ;; 3) If the line starts with ';;#' -- it is a testcase, process it.
    (if (string/starts-with line ";;#")
	;; 3a) Get the input and output data from the testcase.
	(let* ((splitted (split-string line "->"))
	       (fst (car splitted))
	       (snd (cadr splitted))
	       (data (list (chomp (substring fst 3 (length fst)))
			   (chomp snd))))
	  ;; 3b) Set cursor to the line above.
	  (previous-line)
	  ;; 3c) Continue searching for testcases.
	  (get-test-cases (cons data tc)))
      ;; 4) When no more testcases found -- return the accumulated results.
      tc)))

(defun tst-begin (func-name)
  (concat ";;vvv " func-name))

(defun tst-end (func-name)
  (concat ";;^^^ " func-name))

;; The function finds autogenerated testcase and deletes it.
(defun delete-tests-from-buffer (func-name file-name)
  ;; 1) Open tests file.
  (with-current-buffer (find-file tst-file)
    ;; 2) Find test for the specified function.
    (if (search-forward (tst-begin func-name) (point-max) 't)
	;; 3) If the test was found -- find its end and delete the test.
	(progn
	  (previous-line)
	  (beginning-of-line)
	  (set-mark (point))
	  (search-forward (tst-end func-name))
	  (next-line)
	  (kill-region (mark) (point))))))

;; The function generates test for the specified function
(defun add-tests-to-buffer (func-name filename testcases)
  ;; 1) Open tests file.
  (with-current-buffer (find-file tst-file)
    ;; 2) Writ test beginning to the end of the file.
    (end-of-buffer)
    (newline)
    (insert (tst-begin func-name))
    (newline)
    (insert (concat "(deftest " func-name "-test\n(testing \"Autotest of " func-name "\""))
    ;; 3) For each testcase add some code to the test function.
    (dolist (tst testcases)
      (newline)
      (insert "(is (= ("func-name " " (car tst) ") " (cadr tst) "))" ))
    ;; 4) Insert ending of the test function.
    (insert "))\n")
    (insert (tst-end func-name))
    (indent-region 1 (point-max))))

;; Command which generates tests.
(defun generate-test-case ()
  (interactive)
  (let* ((func-name (read-string "Function: " (thing-at-point 'symbol))) ;; ask function name
	 (testcases nil)
	 (file-name (buffer-file-name)) ;; current file name
	 (root-dir (ede-lein2-project-root)) ;; project directory root
	 (src-file (substring file-name (+ 4 (length root-dir)) ;; exclude "src/"
			      (- (length file-name) 4)))        ;; exclude ".clj"
	 (tst-file (concat root-dir "test/" src-file "_test.clj")))
    (save-excursion
      ;; 1) Go to the first comment line.
      (previous-line)
      ;; 2) Search for testcases.
      (setq testcases (get-test-cases nil))
      ;; 3) Delete the test for the current function.
      (delete-tests-from-buffer func-name file-name)
      ;; 4) Generate new test for the current function.
      (add-tests-to-buffer func-name file-name testcases))))