Add ps-mode-tests.el and remove a compilation warning

* lisp/progmodes/ps-mode.el (ps-mode-octal-region): Remove a
string-make-unibyte that apparently had no effect here.
* test/lisp/progmodes/ps-mode-tests.el: New file.

1 files changed, 2 insertions, 1 deletions

diff --git a/lisp/progmodes/ps-mode.el b/lisp/progmodes/ps-mode.el
index 92824b63e68..cf09b98b491 100644
--- a/lisp/progmodes/ps-mode.el
+++ b/lisp/progmodes/ps-mode.el
@@ -738,7 +738,8 @@ Only one `%' is removed, and it has to be in the first column."
         (while (re-search-forward "[\200-\377]" (marker-position endm) t)
           (setq i (1+ i))
           (backward-char)
-          (insert (format "\\%03o" (string-to-char (string-make-unibyte (buffer-substring (point) (1+ (point)))))))
+          (insert (format "\\%03o" (string-to-char
+                                    (buffer-substring (point) (1+ (point))))))
           (delete-char 1))
         (message "%d change%s made" i (if (= i 1) "" "s"))
         (set-marker endm nil)))))