Split image-dired.el into several files (part 1/2)

Use a git trick to split a file while preserving line history (for
"git blame", "git log --follow", etc.):

1) Make exact copies of the original file, in the same commit as
   moving it.  [this commit]

2) Next, trim down the extra copies to contain only the relevant
   parts.

* lisp/image-dired.el: Move from here...
* lisp/image/image-dired-dired.el:
* lisp/image/image-dired-external.el:
* lisp/image/image-dired-tags.el:
* lisp/image/image-dired-util.el:
* lisp/image/image-dired.el: ...to here.

* test/lisp/image-dired-tests.el: Move from here...
* test/lisp/image/image-dired-tests.el: ...to here.

1 files changed, 37 insertions, 0 deletions

diff --git a/test/lisp/image/image-dired-tests.el b/test/lisp/image/image-dired-tests.el
new file mode 100644
index 00000000000..00df72487fd
--- /dev/null
+++ b/test/lisp/image/image-dired-tests.el
@@ -0,0 +1,37 @@
+;;; image-dired-tests.el --- Tests for image-dired.el  -*- lexical-binding: t -*-
+
+;; Copyright (C) 2021-2022 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 'image-dired)
+
+(defun image-dired-test-image-file (name)
+  (expand-file-name
+   name (expand-file-name "data/image"
+                          (or (getenv "EMACS_TEST_DIRECTORY")
+                              "../"))))
+
+(ert-deftest image-dired-tests-get-exif-file-name ()
+  (skip-unless (image-type-available-p 'jpeg))
+  (let ((img (image-dired-test-image-file "black.jpg")))
+    (should (equal (image-dired-get-exif-file-name img)
+                   "2019_09_21_16_22_13_black.jpg"))))
+
+;;; image-dired-tests.el ends here