feat(music): pin the playlist cursor to the number gutter

Vertical motion over thumbnail rows and the stretch-space that right-aligns the metadata drifts point to arbitrary visual columns, usually line end. The rows aren't editable text, so the cursor now lives at the row start (the number column). A buffer-local post-command snap sends every landing back there. Kill, shift (C-up/C-down), and play already act on the whole row, so all track operations happen from the number. An active isearch keeps point until it ends, then the snap lands on the match's row.

1 files changed, 78 insertions, 0 deletions

diff --git a/tests/test-music-config--pin-point.el b/tests/test-music-config--pin-point.el
new file mode 100644
index 00000000..2d6fa916
--- /dev/null
+++ b/tests/test-music-config--pin-point.el
@@ -0,0 +1,78 @@
+;;; test-music-config--pin-point.el --- Tests for the playlist gutter cursor -*- coding: utf-8; lexical-binding: t; -*-
+;;
+;; Author: Craig Jennings <c@cjennings.net>
+;;
+;;; Commentary:
+;; The playlist cursor lives pinned at the start of the row (the number
+;; gutter).  The rows are rendered track lines, not editable text, and
+;; vertical motion over thumbnails and stretch-space drifts point to
+;; arbitrary visual columns (usually line end).  A buffer-local
+;; post-command snap enforces the model for every motion command.  The one
+;; exception is an active isearch, which owns point placement until it ends.
+
+;;; Code:
+
+(require 'ert)
+(require 'cl-lib)
+
+(defvar cj/custom-keymap (make-sparse-keymap)
+  "Stub keymap for testing.")
+
+(require 'music-config)
+
+;;; Normal Cases
+
+(ert-deftest test-music-pin-point-snaps-mid-line-to-bol ()
+  "Normal: point mid-row snaps back to the beginning of the line."
+  (with-temp-buffer
+    (insert "track one\ntrack two\n")
+    (goto-char (point-min))
+    (forward-char 5)
+    (cj/music--pin-point-to-bol)
+    (should (bolp))
+    (should (= (point) (point-min)))))
+
+(ert-deftest test-music-pin-point-noop-at-bol ()
+  "Normal: point already at the row start stays put."
+  (with-temp-buffer
+    (insert "track one\ntrack two\n")
+    (goto-char (point-min))
+    (forward-line 1)
+    (let ((before (point)))
+      (cj/music--pin-point-to-bol)
+      (should (= (point) before)))))
+
+;;; Boundary Cases
+
+(ert-deftest test-music-pin-point-skips-during-isearch ()
+  "Boundary: an active isearch owns point; the pin defers until it ends."
+  (with-temp-buffer
+    (insert "track one\ntrack two\n")
+    (goto-char (point-min))
+    (forward-char 5)
+    (let ((isearch-mode t))
+      (cj/music--pin-point-to-bol))
+    (should-not (bolp))))
+
+(ert-deftest test-music-pin-point-empty-buffer-no-error ()
+  "Boundary: an empty buffer is a no-op, no error."
+  (with-temp-buffer
+    (should-not (cj/music--pin-point-to-bol))
+    (should (bolp))))
+
+;;; Hook wiring
+
+(ert-deftest test-music-pin-point-ensure-wires-post-command-hook ()
+  "Normal: the playlist buffer gets the pin on its buffer-local
+post-command-hook."
+  (let (created)
+    (cl-letf (((symbol-function 'emms-playlist-mode) #'ignore))
+      (unwind-protect
+          (progn
+            (setq created (cj/music--ensure-playlist-buffer))
+            (with-current-buffer created
+              (should (member #'cj/music--pin-point-to-bol post-command-hook))))
+        (when (buffer-live-p created) (kill-buffer created))))))
+
+(provide 'test-music-config--pin-point)
+;;; test-music-config--pin-point.el ends here