refactor(foundation): hygiene pass across early-init, user-constants, system-defaults, chrono-tools

Six small fixes the 2026-05-15 module-by-module re-review surfaced:

- Consolidate `user-home-dir` -- canonical defconst stays in
  early-init.el (package-archive bootstrap needs it before normal
  modules load); user-constants.el switches to a `defvar` with the
  identical `(getenv "HOME")` expression so the module still loads /
  byte-compiles standalone, but at runtime early-init's defconst
  wins.
- Drop the redundant `(autoload 'env-bsd-p ...)` line in
  system-defaults.el.  The `(eval-when-compile (require
  'host-environment))` already exposes the symbol to the byte
  compiler, and at runtime host-environment is loaded earlier in
  init.el.  Added a comment documenting the boundary.
- Convert `cj/debug-modules` and `cj/use-online-repos` from `defvar`
  to `defcustom`, with `:type`, `:group 'cj`, and a top-level
  `(defgroup cj ...)` so both show up in M-x customize.
- Name the package-archive priorities in early-init.el.  Nine new
  defconsts replace the magic numbers (200 / 125 / 120 / 115 / 100 /
  25 / 20 / 15 / 5) with one constant each, plus a header comment
  explaining the local-first ordering and the gnu > nongnu > melpa >
  melpa-stable trust ranking within each tier.
- Delete the 19-line commented-out `use-package time` world-clock
  block in chrono-tools.el.  `time-zones` immediately above is the
  active replacement; git history preserves the old config if anyone
  needs it.
- Add coverage for `cj/tmr-select-sound-file`.  Collapsed the
  prefix-arg branch into a delegation to
  `cj/tmr-reset-sound-to-default` (single reset source) and
  extracted `cj/tmr--available-sound-files` as a pure helper that
  tests directly.  9 ERT tests across Normal / Boundary / Error
  cover the available-sounds helper, the reset path, the prefix-arg
  delegation (no prompt), the normal selection path, and the
  empty-dir / missing-dir / cancel boundaries.

1 files changed, 130 insertions, 0 deletions

diff --git a/tests/test-chrono-tools-tmr-sound.el b/tests/test-chrono-tools-tmr-sound.el
new file mode 100644
index 00000000..2f7dbbab
--- /dev/null
+++ b/tests/test-chrono-tools-tmr-sound.el
@@ -0,0 +1,130 @@
+;;; test-chrono-tools-tmr-sound.el --- Tests for tmr sound selection -*- lexical-binding: t; -*-
+
+;;; Commentary:
+;; Tests for `cj/tmr-select-sound-file' and its helpers in chrono-tools.el.
+;; The prefix-arg branch delegates to `cj/tmr-reset-sound-to-default' so
+;; there's no duplicated reset logic to test twice.
+
+;;; Code:
+
+(require 'ert)
+(require 'cl-lib)
+
+(add-to-list 'load-path (expand-file-name "modules" user-emacs-directory))
+
+;; Stub vars that chrono-tools.el assumes are bound at runtime.
+(defvar sounds-dir nil)
+(defvar tmr-sound-file nil)
+(defvar notification-sound "/tmp/notify.mp3")
+
+(require 'chrono-tools)
+
+;; -------------------------------- helpers
+
+(defun test-chrono-tools--with-sounds-dir (files fn)
+  "Create a temp `sounds-dir' containing FILES, call FN, clean up."
+  (let* ((dir (make-temp-file "test-chrono-tools-tmr-" t))
+         (sounds-dir dir))
+    (unwind-protect
+        (progn
+          (dolist (f files)
+            (with-temp-file (expand-file-name f dir) (insert "x")))
+          (funcall fn dir))
+      (when (file-exists-p dir) (delete-directory dir t)))))
+
+;; -------------------------------- available-sound-files
+
+(ert-deftest test-chrono-tools-available-sounds-normal ()
+  "Normal: returns audio files in `sounds-dir' matching the extension list."
+  (test-chrono-tools--with-sounds-dir
+   '("a.mp3" "b.opus" "readme.txt")
+   (lambda (_dir)
+     (let ((files (cj/tmr--available-sound-files)))
+       (should (member "a.mp3" files))
+       (should (member "b.opus" files))
+       (should-not (member "readme.txt" files))))))
+
+(ert-deftest test-chrono-tools-available-sounds-empty-dir ()
+  "Boundary: empty `sounds-dir' returns nil."
+  (test-chrono-tools--with-sounds-dir
+   '()
+   (lambda (_dir)
+     (should-not (cj/tmr--available-sound-files)))))
+
+(ert-deftest test-chrono-tools-available-sounds-no-dir ()
+  "Boundary: missing `sounds-dir' returns nil."
+  (let ((sounds-dir (expand-file-name (format "missing-%s" (random)) "/tmp")))
+    (should-not (cj/tmr--available-sound-files))))
+
+;; -------------------------------- reset-sound-to-default
+
+(ert-deftest test-chrono-tools-reset-sets-default ()
+  "Reset assigns `notification-sound' to `tmr-sound-file'."
+  (let ((tmr-sound-file "/tmp/other.mp3")
+        (notification-sound "/tmp/the-default.mp3"))
+    (cj/tmr-reset-sound-to-default)
+    (should (equal tmr-sound-file "/tmp/the-default.mp3"))))
+
+;; -------------------------------- select-sound-file
+
+(ert-deftest test-chrono-tools-select-with-prefix-arg-resets ()
+  "Prefix arg delegates to reset, no completing-read prompt."
+  (let ((current-prefix-arg '(4))
+        (tmr-sound-file "/tmp/other.mp3")
+        (notification-sound "/tmp/the-default.mp3")
+        (prompted nil))
+    (cl-letf (((symbol-function 'completing-read)
+               (lambda (&rest _) (setq prompted t) "")))
+      (cj/tmr-select-sound-file))
+    (should-not prompted)
+    (should (equal tmr-sound-file "/tmp/the-default.mp3"))))
+
+(ert-deftest test-chrono-tools-select-normal-sets-selected-file ()
+  "Normal: pick a file, `tmr-sound-file' updates to its full path."
+  (test-chrono-tools--with-sounds-dir
+   '("alpha.mp3" "beta.opus")
+   (lambda (dir)
+     (let ((current-prefix-arg nil)
+           (tmr-sound-file nil)
+           (notification-sound "/tmp/the-default.mp3"))
+       (cl-letf (((symbol-function 'completing-read)
+                  (lambda (&rest _) "alpha.mp3")))
+         (cj/tmr-select-sound-file))
+       (should (equal tmr-sound-file
+                      (expand-file-name "alpha.mp3" dir)))))))
+
+(ert-deftest test-chrono-tools-select-boundary-empty-dir ()
+  "Boundary: empty sounds dir leaves `tmr-sound-file' unchanged."
+  (test-chrono-tools--with-sounds-dir
+   '()
+   (lambda (_dir)
+     (let ((current-prefix-arg nil)
+           (tmr-sound-file "/tmp/keep-me.mp3")
+           (notification-sound "/tmp/the-default.mp3"))
+       (cj/tmr-select-sound-file)
+       (should (equal tmr-sound-file "/tmp/keep-me.mp3"))))))
+
+(ert-deftest test-chrono-tools-select-boundary-missing-dir ()
+  "Boundary: missing sounds dir leaves `tmr-sound-file' unchanged."
+  (let ((current-prefix-arg nil)
+        (sounds-dir (expand-file-name (format "missing-%s" (random)) "/tmp"))
+        (tmr-sound-file "/tmp/keep-me.mp3")
+        (notification-sound "/tmp/the-default.mp3"))
+    (cj/tmr-select-sound-file)
+    (should (equal tmr-sound-file "/tmp/keep-me.mp3"))))
+
+(ert-deftest test-chrono-tools-select-boundary-cancel-returns-no-change ()
+  "Boundary: empty completion result leaves `tmr-sound-file' unchanged."
+  (test-chrono-tools--with-sounds-dir
+   '("alpha.mp3")
+   (lambda (_dir)
+     (let ((current-prefix-arg nil)
+           (tmr-sound-file "/tmp/keep-me.mp3")
+           (notification-sound "/tmp/the-default.mp3"))
+       (cl-letf (((symbol-function 'completing-read)
+                  (lambda (&rest _) "")))
+         (cj/tmr-select-sound-file))
+       (should (equal tmr-sound-file "/tmp/keep-me.mp3"))))))
+
+(provide 'test-chrono-tools-tmr-sound)
+;;; test-chrono-tools-tmr-sound.el ends here