[PATCH] Testing: Add tests for `org-tags-sort-function'

[Morgan Smith <Morgan.J.Smith@outlook.com>]

* testing/lisp/test-org-agenda.el (test-org-agenda/tags-sorting): New
test.
---

Hello!

I just recently sent in a patch to add a new possible value for
`org-tags-sort-function'.  To ease discussion there, I thought I'd add a nice
little test here so I can later show off the feature I'm trying to add.

Do notice that TODO I put in the comment though.  Not sure what the solution to
that should be.

It would be nice to accept this patch even with the TODO so I can make patches
in the other discussion that extend this test.  Or I suppose I could try being
patient.  That doesn't sound as fun though.

Thanks,

Morgan

 testing/lisp/test-org-agenda.el | 49 +++++++++++++++++++++++++++++++++
 1 file changed, 49 insertions(+)

diff --git a/testing/lisp/test-org-agenda.el b/testing/lisp/test-org-agenda.el
index 778f91e8e..c1092df3b 100644
--- a/testing/lisp/test-org-agenda.el
+++ b/testing/lisp/test-org-agenda.el
@@ -655,6 +655,55 @@ Sunday      7 January 2024
               (buffer-string))))))
       (org-test-agenda--kill-all-agendas))))
 
+(ert-deftest test-org-agenda/tags-sorting ()
+  "Test if `org-agenda' sorts tags according to `org-tags-sort-function'."
+  (let ((org-agenda-custom-commands
+         '(("f" "no fluff" todo ""
+            ((org-agenda-todo-keyword-format "")
+             (org-agenda-overriding-header "")
+             (org-agenda-prefix-format "")
+             (org-agenda-remove-tags t)
+             (org-agenda-sorting-strategy '(tag-up))))))
+        ;; Sorting doesn't care about `org-tag-alist'.  This is only
+        ;; here for later when we add sorting methods that do
+        (org-tag-alist
+         '((:startgrouptag)
+           ("group_a")
+           (:grouptags)
+           ("tag_a_1")
+           ("tag_a_2")
+           (:endgrouptag)
+           (:startgroup)
+           ("tag_b_1")
+           ("tag_b_2")
+           (:endgroup)
+           ("groupless")
+           ("lonely"))))
+    (org-test-agenda-with-agenda
+     (string-join
+      '("* TODO group_a :group_a:"
+        "* TODO tag_a_1 :tag_a_1:"
+        "* TODO tag_a_2 :tag_a_2:"
+        "* TODO tag_b_1 :tag_b_1:"
+        "* TODO tag_b_2 :tag_b_2:"
+        "* TODO groupless :groupless:"
+        "* TODO lonely :lonely:")
+      "\n")
+     (dolist (org-tags-sort-function '(nil org-string< org-string>))
+       (should
+        (string-equal
+         (progn
+           (org-agenda nil "f")
+           (substring-no-properties (buffer-string)))
+         (pcase org-tags-sort-function
+           ;; TODO: a value of `nil' sorts it!  That's not what the
+           ;; customize menu of `org-tags-sort-function' says!  It
+           ;; says "No sorting".
+           ((or 'nil 'org-string<)
+            "group_a\ngroupless\nlonely\ntag_a_1\ntag_a_2\ntag_b_1\ntag_b_2\n")
+           ('org-string>
+            "tag_b_2\ntag_b_1\ntag_a_2\ntag_a_1\nlonely\ngroupless\ngroup_a\n"))))))))
+
 (ert-deftest test-org-agenda/goto-date ()
   "Test `org-agenda-goto-date'."
   (unwind-protect
-- 
2.45.1