Add an Exif parsing library

* lisp/image/exif.el: New file (bug#23070).

* test/lisp/image/exif-tests.el: Add some basic tests.

2 files changed, 44 insertions, 0 deletions

diff --git a/test/data/image/black.jpg b/test/data/image/black.jpg
new file mode 100644
index 00000000000..be9af2a9a05
--- /dev/null
+++ b/test/data/image/black.jpg
diff --git a/test/lisp/image/exif-tests.el b/test/lisp/image/exif-tests.el
new file mode 100644
index 00000000000..d6b46980d77
--- /dev/null
+++ b/test/lisp/image/exif-tests.el
@@ -0,0 +1,44 @@
+;;; exif-tests.el --- tests for exif.el -*- lexical-binding: t -*-
+
+;; Copyright (C) 2019 Free Software Foundation, Inc.
+
+;; 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/>.
+
+;;; Code:
+
+(require 'ert)
+(require 'exif)
+(require 'seq)
+
+(defun test-image-file (name)
+  (expand-file-name
+   name (expand-file-name "data/image"
+                          (or (getenv "EMACS_TEST_DIRECTORY")
+                              "../../"))))
+
+(defun exif-elem (exif elem)
+  (plist-get (seq-find (lambda (e)
+                         (eq elem (plist-get e :tag-name)))
+                       exif)
+             :value))
+
+(ert-deftest test-exif-parse ()
+  (let ((exif (exif-parse (test-image-file "black.jpg"))))
+    (should (equal (exif-elem exif 'make) "Panasonic"))
+    (should (equal (exif-elem exif 'orientation) 1))
+    (should (equal (exif-elem exif 'x-resolution) '(180 . 1)))))
+
+;;; exif-tests.el ends here