Use lexical-binding in mail-utils.el and add tests

* lisp/mail/mail-utils.el: Use lexical-binding.
* test/lisp/mail/mail-utils-tests.el: New file.

lisp/mail/mail-utils.el

@@ -1,4 +1,4 @@
-;;; mail-utils.el --- utility functions used both by rmail and rnews
+;;; mail-utils.el --- utility functions used both by rmail and rnews  -*- lexical-binding: t -*-
 
 ;; Copyright (C) 1985, 2001-2021 Free Software Foundation, Inc.
 
@@ -46,6 +46,7 @@ also the To field, unless this would leave an empty To field."
   :type '(choice regexp (const :tag "Your Name" nil))
   :group 'mail)
 
+(defvar epa-inhibit)
 ;; Returns t if file FILE is an Rmail file.
 ;;;###autoload
 (defun mail-file-babyl-p (file)
@@ -58,6 +59,7 @@ also the To field, unless this would leave an empty To field."
 (defun mail-string-delete (string start end)
   "Return a string containing all of STRING except the part
 from START (inclusive) to END (exclusive)."
+  ;; FIXME: This is not used anywhere.  Make obsolete?
   (if (null end) (substring string 0 start)
     (concat (substring string 0 start)
 	    (substring string end nil))))

test/lisp/mail/mail-utils-tests.el

@@ -0,0 +1,104 @@
+;;; mail-utils-tests.el --- tests for mail-utils.el  -*- lexical-binding: t -*-
+
+;; Copyright (C) 2021 Free Software Foundation, Inc.
+
+;; Author: Stefan Kangas <stefankangas@gmail.com>
+
+;; This file is part of GNU Emacs.
+
+;; GNU Emacs 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.
+
+;; GNU Emacs 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 GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.
+
+;;; Commentary:
+
+;;; Code:
+
+(require 'ert)
+(require 'sasl)
+(require 'mail-utils)
+
+(ert-deftest mail-utils-tests-mail-quote-printable ()
+  (should (equal (mail-quote-printable "abc") "abc"))
+  (should (equal (mail-quote-printable "åäö") "=E5=E4=F6"))
+  (should (equal (mail-quote-printable "åäö" t) "=?ISO-8859-1?Q?=E5=E4=F6?=")))
+
+(ert-deftest mail-utils-tests-mail-quote-printable-region ()
+  (with-temp-buffer
+    (insert "?=\"\"")
+    (mail-quote-printable-region (point-min) (point-max))
+    (should (equal (buffer-string) "=3F=3D=22=22")))
+  (with-temp-buffer
+    (insert "x")
+    (mail-quote-printable-region (point-min) (point-max) t)
+    (should (equal (buffer-string) "=?=?ISO-8859-1?Q?x"))))
+
+(ert-deftest mail-utils-tests-mail-unquote-printable ()
+  (should (equal (mail-unquote-printable "=E5=E4=F6") "åäö"))
+  (should (equal (mail-unquote-printable "=?ISO-8859-1?Q?=E5=E4=F6?=" t) "åäö")))
+
+(ert-deftest mail-utils-tests-mail-unquote-printable-region ()
+  (with-temp-buffer
+    (insert "=E5=E4=F6")
+    (mail-unquote-printable-region (point-min) (point-max))
+    (should (equal (buffer-string) "åäö")))
+  (with-temp-buffer
+    (insert "=?ISO-8859-1?Q?=E5=E4=F6?=")
+    (mail-unquote-printable-region (point-min) (point-max) t)
+    (should (equal (buffer-string) "åäö"))))
+
+(ert-deftest mail-utils-tests-mail-strip-quoted-names ()
+  (should (equal (mail-strip-quoted-names
+                  "\"foo\" <foo@example.org>, bar@example.org")
+                 "foo@example.org, bar@example.org")))
+
+(ert-deftest mail-utils-tests-mail-dont-reply-to ()
+  (let ((mail-dont-reply-to-names "foo@example.org"))
+    (should (equal (mail-dont-reply-to "foo@example.org, bar@example.org")
+                   "bar@example.org"))))
+
+
+(ert-deftest mail-utils-tests-mail-fetch-field ()
+  (with-temp-buffer
+    (insert "Foo: bar\nBaz: zut")
+    (should (equal (mail-fetch-field "Foo") "bar"))))
+
+(ert-deftest mail-utils-tests-mail-parse-comma-list ()
+  (with-temp-buffer
+    (insert "foo@example.org,bar@example.org,baz@example.org")
+    (goto-char (point-min))
+    (should (equal (mail-parse-comma-list)
+                   '("baz@example.org" "bar@example.org" "foo@example.org")))))
+
+(ert-deftest mail-utils-tests-mail-comma-list-regexp ()
+  (should (equal (mail-comma-list-regexp
+                  "foo@example.org,bar@example.org,baz@example.org")
+                 "foo@example.org\\|bar@example.org\\|baz@example.org")))
+
+(ert-deftest mail-utils-tests-mail-rfc822-time-zone ()
+  (should (stringp (mail-rfc822-time-zone (current-time)))))
+
+(ert-deftest mail-utils-test-mail-rfc822-date/contains-year ()
+  (should (string-match (rx " 20" digit digit " ")
+                        (mail-rfc822-date))))
+
+(ert-deftest mail-utils-test-mail-mbox-from ()
+  (with-temp-buffer
+    (insert "Subject: Hello
+From: jrh@example.org
+To: emacs-devel@gnu.org
+Date: Sun, 07 Feb 2021 22:46:37 -0500")
+    (should (equal (mail-mbox-from)
+                   "From jrh@example.org Sun Feb  7 22:46:37 2021\n"))))
+
+(provide 'mail-utils-tests)
+;;; mail-utils-tests.el ends here