utils: Return eof-object from read-bytes-till on end of file.

* email/utils.scm (read-bytes-till): Return eof-object, not #vu8(), on
end of file.
* tests/utils.scm: New file.
* Makefile.am (SCM_TESTS): Register it.

3 files changed, 38 insertions, 3 deletions

diff --git a/Makefile.am b/Makefile.am
index a8df177..4f3f296 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -51,7 +51,8 @@ TEST_EXTENSIONS = .scm
 
 SCM_TESTS =			\
   tests/email.scm		\
-  tests/quoted-printable.scm
+  tests/quoted-printable.scm	\
+  tests/utils.scm
 
 TESTS = $(SCM_TESTS)
 
diff --git a/email/utils.scm b/email/utils.scm
index 2040b21..8344c6b 100644
--- a/email/utils.scm
+++ b/email/utils.scm
@@ -79,8 +79,9 @@ reached. If SEQUENCE is seen, unget it to PORT and return."
        (else (put-u8 out octet)
              (read-bytes-and-write-till in out sequence)))))
 
-  (call-with-bytevector-output-port
-   (cut read-bytes-and-write-till port <> sequence)))
+  (let ((bv (call-with-bytevector-output-port
+             (cut read-bytes-and-write-till port <> sequence))))
+    (if (bytevector=? bv (make-bytevector 0)) (eof-object) bv)))
 
 (define (get-line-with-delimiter port)
   "Read a line from PORT and return it as a string including the
diff --git a/tests/utils.scm b/tests/utils.scm
new file mode 100644
index 0000000..f54cfdd
--- /dev/null
+++ b/tests/utils.scm
@@ -0,0 +1,33 @@
+;;; guile-email --- Guile email parser
+;;; Copyright © 2019 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 utils)
+             (rnrs bytevectors)
+             (rnrs io ports)
+             (srfi srfi-26)
+             (srfi srfi-64))
+
+(test-begin "utils")
+
+(test-assert "read-bytes-till returns eof-object on end of file"
+  (eof-object?
+   (call-with-port (open-bytevector-input-port (make-bytevector 0))
+                   (cut read-bytes-till <> (make-bytevector 1)))))
+
+(test-end "utils")