tests: Add tests for (email base64).

* tests/encoding.scm: Move common code for encoding tests to this new
file.
* tests/quoted-printable.scm: Load encoding.scm.
* tests/base64.scm: New file.
* Makefile.am (SCM_TESTS): Register tests/base64.scm.

3 files changed, 110 insertions, 11 deletions

diff --git a/tests/base64.scm b/tests/base64.scm
new file mode 100644
index 0000000..c200f81
--- /dev/null
+++ b/tests/base64.scm
@@ -0,0 +1,76 @@
+;;; guile-email --- Guile email parser
+;;; Copyright © 2020 Arun Isaac <arunisaac@systemreboot.net>
+;;;
+;;; This file is part of guile-email.
+;;;
+;;; guile-email is free software; you can redistribute it and/or modify
+;;; it under the terms of the GNU Affero General Public License as
+;;; published by the Free Software Foundation; either version 3 of the
+;;; License, or (at your option) any later version.
+;;;
+;;; guile-email 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
+;;; Affero General Public License for more details.
+;;;
+;;; You should have received a copy of the GNU Affero General Public
+;;; License along with guile-email.  If not, see
+;;; <http://www.gnu.org/licenses/>.
+
+(use-modules (email base64)
+             (ice-9 iconv))
+
+(load "encoding.scm")
+
+(define (string-has-only-valid-base64-characters? str)
+  (string-every (char-set-union
+                 (char-set #\newline #\return #\space)
+                 (ucs-range->char-set (char->integer #\A) (1+ (char->integer #\Z)))
+                 (ucs-range->char-set (char->integer #\a) (1+ (char->integer #\z)))
+                 (ucs-range->char-set (char->integer #\0) (1+ (char->integer #\9)))
+                 (char-set #\+ #\/ #\=))
+                str))
+
+(test-begin "base64")
+
+(let ((decoded-text
+       "Man is distinguished, not only by his reason, but by this singular passion from other animals, which is a lust of the mind, that by a perseverance of delight in the continued and indefatigable generation of knowledge, exceeds the short vehemence of any carnal pleasure.")
+      (encoded-text
+       "TWFuIGlzIGRpc3Rpbmd1aXNoZWQsIG5vdCBvbmx5IGJ5IGhpcyByZWFzb24sIGJ1dCBieSB0aGlz
+IHNpbmd1bGFyIHBhc3Npb24gZnJvbSBvdGhlciBhbmltYWxzLCB3aGljaCBpcyBhIGx1c3Qgb2Yg
+dGhlIG1pbmQsIHRoYXQgYnkgYSBwZXJzZXZlcmFuY2Ugb2YgZGVsaWdodCBpbiB0aGUgY29udGlu
+dWVkIGFuZCBpbmRlZmF0aWdhYmxlIGdlbmVyYXRpb24gb2Yga25vd2xlZGdlLCBleGNlZWRzIHRo
+ZSBzaG9ydCB2ZWhlbWVuY2Ugb2YgYW55IGNhcm5hbCBwbGVhc3VyZS4=")
+      (charset "UTF-8"))
+  (test-equal "base64 wikipedia example: decoding"
+    (bytevector->string (base64-decode encoded-text) charset)
+    decoded-text)
+
+  (test-equal "base64 wikipedia example: encoding"
+    (base64-encode
+     (string->bytevector decoded-text charset))
+    encoded-text)
+
+  (test-assert "base64 wikipedia example: encoded output should not be more than 76 columns wide"
+    (each-line-has-a-maximum-of-76-characters?
+     (base64-encode
+      (string->bytevector decoded-text charset)))))
+
+(let ((x (random-bytevector 1000)))
+  (test-equal "base64 random bytevector: base64-encode and base64-decode are inverses of each other"
+    (base64-decode (base64-encode x))
+    x))
+
+(test-assert "base64 random bytevector: encoded output should not be more than 76 columns wide"
+  (each-line-has-a-maximum-of-76-characters?
+   (base64-encode (random-bytevector 1000))))
+
+(test-assert "base64 random bytevector: encoded output must only consist of characters from the base64 alphabet"
+  (string-has-only-valid-base64-characters?
+   (base64-encode (random-bytevector 1000))))
+
+(test-equal "base64 decoding should ignore invalid characters"
+  (bytevector->string (base64-decode "..TWFu,") "utf-8")
+  "Man")
+
+(test-end "base64")
diff --git a/tests/encoding.scm b/tests/encoding.scm
new file mode 100644
index 0000000..d623d48
--- /dev/null
+++ b/tests/encoding.scm
@@ -0,0 +1,33 @@
+;;; guile-email --- Guile email parser
+;;; Copyright © 2020 Arun Isaac <arunisaac@systemreboot.net>
+;;;
+;;; This file is part of guile-email.
+;;;
+;;; guile-email is free software; you can redistribute it and/or modify
+;;; it under the terms of the GNU Affero General Public License as
+;;; published by the Free Software Foundation; either version 3 of the
+;;; License, or (at your option) any later version.
+;;;
+;;; guile-email 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
+;;; Affero General Public License for more details.
+;;;
+;;; You should have received a copy of the GNU Affero General Public
+;;; License along with guile-email.  If not, see
+;;; <http://www.gnu.org/licenses/>.
+
+(use-modules (rnrs bytevectors)
+             (srfi srfi-1))
+
+(set! *random-state* (random-state-from-platform))
+
+(define (random-bytevector len)
+  "Return a random bytevector of length LEN."
+  (u8-list->bytevector
+   (map (lambda _ (random 256)) (iota len))))
+
+(define (each-line-has-a-maximum-of-76-characters? str)
+  (every (lambda (line)
+           (<= (string-length line) 76))
+         (string-split str #\newline)))
diff --git a/tests/quoted-printable.scm b/tests/quoted-printable.scm
index 267011a..0b5b462 100644
--- a/tests/quoted-printable.scm
+++ b/tests/quoted-printable.scm
@@ -23,17 +23,7 @@
              (srfi srfi-1)
              (srfi srfi-64))
 
-(set! *random-state* (random-state-from-platform))
-
-(define (random-bytevector len)
-  "Return a random bytevector of length LEN."
-  (u8-list->bytevector
-   (map (lambda _ (random 256)) (iota len))))
-
-(define (each-line-has-a-maximum-of-76-characters? str)
-  (every (lambda (line)
-           (<= (string-length line) 76))
-         (string-split str #\newline)))
+(load "encoding.scm")
 
 (define (string-has-only-quoted-printable-valid-characters? str)
   (string-every (char-set-union