--- /dev/null
+;;; qp-tests.el --- Tests for qp.el -*- lexical-binding:t; coding:utf-8 -*-
+
+;; Copyright (C) 2020 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 'qp)
+
+;; Quote by Antoine de Saint-Exupéry, Citadelle (1948)
+;; from https://en.wikipedia.org/wiki/Quoted-printable
+(defvar qp-tests-quote-qp
+ (concat "J'interdis aux marchands de vanter trop leurs marchandises. Car ils se font =\n"
+ "vite p=C3=A9dagogues et t'enseignent comme but ce qui n'est par essence qu'=\n"
+ "un moyen, et te trompant ainsi sur la route =C3=A0 suivre les voil=C3=A0 bi=\n"
+ "ent=C3=B4t qui te d=C3=A9gradent, car si leur musique est vulgaire ils te f=\n"
+ "abriquent pour te la vendre une =C3=A2me vulgaire."))
+(defvar qp-tests-quote-utf8
+ (concat "J'interdis aux marchands de vanter trop leurs marchandises. Car ils se font "
+ "vite pédagogues et t'enseignent comme but ce qui n'est par essence qu'"
+ "un moyen, et te trompant ainsi sur la route à suivre les voilà bi"
+ "entôt qui te dégradent, car si leur musique est vulgaire ils te f"
+ "abriquent pour te la vendre une âme vulgaire."))
+
+(ert-deftest qp-test--quoted-printable-decode-region ()
+ (with-temp-buffer
+ (insert qp-tests-quote-qp)
+ (encode-coding-region (point-min) (point-max) 'utf-8)
+ (quoted-printable-decode-region (point-min) (point-max) 'utf-8)
+ (should (equal (buffer-string) qp-tests-quote-utf8))))
+
+(ert-deftest qp-test--quoted-printable-decode-string ()
+ (should (equal (quoted-printable-decode-string "foo!") "foo!"))
+ (should (equal (quoted-printable-decode-string "=0C") "\^L"))
+ (should (equal (quoted-printable-decode-string "=3D") "="))
+ (should (equal (quoted-printable-decode-string "=A1Hola, se=F1or!?")
+ "\241Hola, se\361or!?")))
+
+(ert-deftest qp-test--quoted-printable-encode-region ()
+ (with-temp-buffer
+ (insert (make-string 26 ?=))
+ ;; (encode-coding-region (point-min) (point-max) 'utf-8)
+ (quoted-printable-encode-region (point-min) (point-max) t)
+ (should (equal (buffer-string)
+ (concat "=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D"
+ "=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=\n=3D")))))
+
+(ert-deftest qp-test--quoted-printable-encode-string ()
+ (should (equal (quoted-printable-encode-string "\241Hola, se\361or!?")
+ "=A1Hola, se=F1or!?"))
+ ;; Multibyte character.
+ (should-error (quoted-printable-encode-string "å")))
+
+(provide 'qp-tests)
+;;; qp-tests.el ends here