Add tests for shorthand fn

clojure-mode.el

@@ -2805,7 +2805,7 @@ END marks the end of the fn expression"
   (when-let (beg (clojure-string-start))
     (goto-char beg))
   (if (or (looking-at-p "#(")
-          (forward-char 1)
+          (ignore-errors (forward-char 1))
           (re-search-backward "#(" (save-excursion (beginning-of-defun) (point)) 'noerror))
       (let* ((end (save-excursion (clojure-forward-logical-sexp) (point-marker)))
              (argspec (clojure--gather-shorthand-args))

test/clojure-mode-convert-fn-test.el

@@ -0,0 +1,72 @@
+;;; clojure-mode-convert-fn-test.el --- Clojure Mode: convert fn syntax -*- lexical-binding: t; -*-
+
+;; This file is not part of GNU Emacs.
+
+;; 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:
+
+;; Tests for clojure-convert-shorthand-fn
+
+;;; Code:
+
+(require 'clojure-mode)
+(require 'buttercup)
+
+(describe "clojure-convert-shorthand-fn"
+  :var (names)
+
+  (before-each
+    (spy-on 'read-string
+            :and-call-fake (lambda (_) (or (pop names) (error "")))))
+
+  (when-refactoring-it "should convert 0-arg fns"
+    "#(rand)"
+    "(fn [] (rand))"
+    (clojure-convert-shorthand-fn))
+
+  (when-refactoring-it "should convert 1-arg fns"
+    "#(= % 1)"
+    "(fn [x] (= x 1))"
+    (setq names '("x"))
+    (clojure-convert-shorthand-fn))
+
+  (when-refactoring-it "should convert 2-arg fns"
+    "#(conj (pop %1) (assoc (peek %1) %2 (* %2 %2)))"
+    "(fn [acc x] (conj (pop acc) (assoc (peek acc) x (* x x))))"
+    (setq names '("acc" "x"))
+    (clojure-convert-shorthand-fn))
+
+  (when-refactoring-it "should convert variadic fns"
+    ;; from https://hypirion.com/musings/swearjure
+    "#(* (`[~@%&] (+))
+   ((% (+)) % (- (`[~@%&] (+)) (*))))"
+    "(fn [v & vs] (* (`[~@vs] (+))
+   ((v (+)) v (- (`[~@vs] (+)) (*)))))"
+    (setq names '("v" "vs"))
+    (clojure-convert-shorthand-fn))
+
+  (when-refactoring-it "should ignore strings and comments"
+    "#(format \"%2\" ;; FIXME: %2 is an illegal specifier
+   %7) "
+    "(fn [_ _ _ _ _ _ id] (format \"%2\" ;; FIXME: %2 is an illegal specifier
+   id)) "
+    (setq names '("_" "_" "_" "_" "_" "_" "id"))
+    (clojure-convert-shorthand-fn)))
+
+
+(provide 'clojure-mode-convert-fn-test)
+
+
+;;; clojure-mode-convert-fn-test.el ends here