test(org-noter-config): cover preferred-split, slug, template, predicates

Four new test files for the pure-and-near-pure helpers in
org-noter-config.el. The interactive heavyweights (cj/org-noter-start,
cj/org-noter-insert-note-dwim, cj/org-noter--toggle-notes-window,
cj/org-noter--find-notes-file, cj/org-noter--create-notes-file) are
out of scope for this pass — they need org-noter loaded and a real
session, or a substantial internal/wrapper split before they can be
tested without spinning up real PDFs and EPUBs.

- preferred-split: 5 tests walking the 1.4 width-to-height threshold
  from both sides plus a square-frame boundary.
- title-to-slug: 7 tests covering multi-word, single-word, mixed
  punctuation, leading/trailing junk, collapsed runs, digits, and
  empty input.
- generate-notes-template: 5 tests with org-id-uuid mocked, asserting
  the rendered template carries the UUID, the dual ROAM_REFS /
  NOTER_DOCUMENT pointers, the title-and-category lines, the
  ReadingNotes filetag, and the trailing Notes heading.
- predicates: 13 tests covering cj/org-noter--in-document-p,
  cj/org-noter--in-notes-file-p, cj/org-noter--session-active-p,
  cj/org-noter--get-document-path, and cj/org-noter--extract-document-title.
  Mocks derived-mode-p, org-entry-get, and buffer-file-name at the
  boundary so the suite doesn't require pdf-tools or nov.

The require chain in each test file is user-constants → keybindings →
org-noter-config because cj/org-noter-notes-directory captures
roam-dir from user-constants and the prefix-map binding at the bottom
of org-noter-config references cj/custom-keymap.

30 new tests, all passing. Full suite green.

1 files changed, 52 insertions, 0 deletions

diff --git a/tests/test-org-noter-config--preferred-split.el b/tests/test-org-noter-config--preferred-split.el
new file mode 100644
index 00000000..c99d63f4
--- /dev/null
+++ b/tests/test-org-noter-config--preferred-split.el
@@ -0,0 +1,52 @@
+;;; test-org-noter-config--preferred-split.el --- Tests for cj/org-noter--preferred-split -*- lexical-binding: t; -*-
+
+;;; Commentary:
+;; Tests for `cj/org-noter--preferred-split'. The function returns
+;; `horizontal-split' when the frame's width-to-height ratio exceeds
+;; 1.4, otherwise `vertical-split'. Tests mock the frame-pixel-*
+;; primitives to walk the threshold from both sides.
+
+;;; Code:
+
+(require 'ert)
+(require 'cl-lib)
+
+(add-to-list 'load-path (expand-file-name "modules" user-emacs-directory))
+(require 'user-constants)
+(require 'keybindings)
+(require 'org-noter-config)
+
+(defmacro test-org-noter-config--with-frame-size (width height &rest body)
+  "Run BODY with `frame-pixel-width' / `frame-pixel-height' mocked to WIDTH and HEIGHT."
+  (declare (indent 2) (debug t))
+  `(cl-letf (((symbol-function 'frame-pixel-width) (lambda (&optional _) ,width))
+             ((symbol-function 'frame-pixel-height) (lambda (&optional _) ,height)))
+     ,@body))
+
+(ert-deftest test-org-noter-config-preferred-split-wide-returns-horizontal ()
+  "Normal: a 16:9 wide frame returns horizontal-split (side-by-side)."
+  (test-org-noter-config--with-frame-size 1920 1080
+    (should (eq 'horizontal-split (cj/org-noter--preferred-split)))))
+
+(ert-deftest test-org-noter-config-preferred-split-tall-returns-vertical ()
+  "Normal: a tall portrait frame returns vertical-split (stacked)."
+  (test-org-noter-config--with-frame-size 800 1200
+    (should (eq 'vertical-split (cj/org-noter--preferred-split)))))
+
+(ert-deftest test-org-noter-config-preferred-split-square-returns-vertical ()
+  "Boundary: a square frame is below the 1.4 threshold; returns vertical."
+  (test-org-noter-config--with-frame-size 1000 1000
+    (should (eq 'vertical-split (cj/org-noter--preferred-split)))))
+
+(ert-deftest test-org-noter-config-preferred-split-just-above-threshold-horizontal ()
+  "Boundary: a width-to-height ratio of 1.5 returns horizontal."
+  (test-org-noter-config--with-frame-size 1500 1000
+    (should (eq 'horizontal-split (cj/org-noter--preferred-split)))))
+
+(ert-deftest test-org-noter-config-preferred-split-just-below-threshold-vertical ()
+  "Boundary: a width-to-height ratio of 1.3 returns vertical."
+  (test-org-noter-config--with-frame-size 1300 1000
+    (should (eq 'vertical-split (cj/org-noter--preferred-split)))))
+
+(provide 'test-org-noter-config--preferred-split)
+;;; test-org-noter-config--preferred-split.el ends here