test(music-config): cover playlist commands + random-aware navigation

Second pass on music-config. The first batch covered assertion guards, the M3U picker, EMMS lazy setup, and the smaller commands. This batch covers the remaining interactive playlist commands and the random-history navigation pair:

- `cj/music-playlist-load`: loads the selected file via `emms-play-playlist`, errors when the chosen file isn't on disk.
- `cj/music-playlist-reload`: replays the buffer-local playlist file, errors when none is associated.
- `cj/music-playlist-edit`: opens the M3U file in another window when the buffer is clean.
- `cj/music-next`: delegates to `emms-next` or `emms-random` based on `emms-random-playlist`.
- `cj/music-previous`: emms-previous when not random; with random + history pops the top, finds it in the playlist, selects + starts; with random + no history messages; with random and a missing track, messages.
- `cj/music--consume-track`: no-op when consume-mode is off, kills the selected track when on.

EMMS primitives (`emms-playlist-clear`, `emms-play-playlist`, `emms-stop`, `emms-random`, `emms-next`, `emms-previous`, `emms-start`, `emms-playlist-select`, `emms-playlist-mode-kill-track`) are stubbed throughout.

1 files changed, 261 insertions, 0 deletions

diff --git a/tests/test-music-config-playlist-commands.el b/tests/test-music-config-playlist-commands.el
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+;;; test-music-config-playlist-commands.el --- Tests for the music-config playlist commands -*- coding: utf-8; lexical-binding: t; -*-
+;;
+;; Author: Craig Jennings <c@cjennings.net>
+;;
+;;; Commentary:
+;; Sibling tests cover the pure helpers and a first batch of small
+;; commands.  This file covers the remaining interactive playlist
+;; commands plus the random-aware navigation pair:
+;;
+;;   cj/music-playlist-load
+;;   cj/music-playlist-reload
+;;   cj/music-playlist-edit
+;;   cj/music-next
+;;   cj/music-previous
+;;   cj/music--consume-track
+;;
+;; EMMS primitives (`emms-playlist-clear', `emms-play-playlist',
+;; `emms-stop', `emms-random', `emms-next', `emms-previous',
+;; `emms-start', `emms-playlist-select') are stubbed throughout.
+;;
+;;; Code:
+
+(require 'ert)
+(require 'cl-lib)
+(require 'testutil-general)
+
+(defvar-keymap cj/custom-keymap :doc "Stub keymap for testing")
+
+(let ((emms-dir (car (file-expand-wildcards
+                      (expand-file-name "elpa/emms-*" user-emacs-directory)))))
+  (when emms-dir
+    (add-to-list 'load-path emms-dir)))
+
+(require 'emms)
+(require 'emms-playlist-mode)
+(require 'music-config)
+
+(defun test-mc-pc--setup ()
+  "Per-test setup."
+  (cj/create-test-base-dir)
+  (let ((buf (get-buffer-create cj/music-playlist-buffer-name)))
+    (with-current-buffer buf
+      (emms-playlist-mode)
+      (setq emms-playlist-buffer-p t)
+      (setq cj/music-playlist-file nil))
+    (setq emms-playlist-buffer buf)
+    buf))
+
+(defun test-mc-pc--teardown ()
+  "Per-test cleanup."
+  (when-let ((buf (get-buffer cj/music-playlist-buffer-name)))
+    (with-current-buffer buf
+      (setq cj/music-playlist-file nil))
+    (kill-buffer buf))
+  (cj/delete-test-base-dir))
+
+;;; cj/music-playlist-load
+
+(ert-deftest test-mc-playlist-load-normal-loads-selected-file ()
+  "Normal: user picks an existing playlist; load wires it via emms-play-playlist."
+  (test-mc-pc--setup)
+  (unwind-protect
+      (let ((tmp (make-temp-file "test-mc-pl-" nil ".m3u"))
+            (played nil))
+        (with-temp-file tmp (insert "track.mp3\n"))
+        (cl-letf (((symbol-function 'cj/music--get-m3u-files)
+                   (lambda () (list (cons "test.m3u" tmp))))
+                  ((symbol-function 'completing-read)
+                   (lambda (&rest _) "test.m3u"))
+                  ((symbol-function 'emms-playlist-clear) #'ignore)
+                  ((symbol-function 'emms-play-playlist)
+                   (lambda (f) (setq played f)))
+                  ((symbol-function 'message) #'ignore))
+          (cj/music-playlist-load))
+        (should (equal played tmp))
+        (delete-file tmp))
+    (test-mc-pc--teardown)))
+
+(ert-deftest test-mc-playlist-load-error-on-missing-file ()
+  "Error: user picks a name whose file isn't on disk -> user-error."
+  (test-mc-pc--setup)
+  (unwind-protect
+      (cl-letf (((symbol-function 'cj/music--get-m3u-files)
+                 (lambda () '(("ghost.m3u" . "/nope/ghost.m3u"))))
+                ((symbol-function 'completing-read)
+                 (lambda (&rest _) "ghost.m3u"))
+                ((symbol-function 'emms-playlist-clear) #'ignore)
+                ((symbol-function 'emms-play-playlist) #'ignore))
+        (should-error (cj/music-playlist-load) :type 'user-error))
+    (test-mc-pc--teardown)))
+
+;;; cj/music-playlist-reload
+
+(ert-deftest test-mc-playlist-reload-replays-current-file ()
+  "Normal: with a valid playlist file the function plays it again."
+  (test-mc-pc--setup)
+  (unwind-protect
+      (let ((tmp (make-temp-file "test-mc-reload-" nil ".m3u"))
+            (played nil))
+        (with-temp-file tmp (insert "track.mp3\n"))
+        (with-current-buffer cj/music-playlist-buffer-name
+          (setq cj/music-playlist-file tmp))
+        (cl-letf (((symbol-function 'emms-playlist-clear) #'ignore)
+                  ((symbol-function 'emms-play-playlist)
+                   (lambda (f) (setq played f)))
+                  ((symbol-function 'message) #'ignore))
+          (cj/music-playlist-reload))
+        (should (equal played tmp))
+        (delete-file tmp))
+    (test-mc-pc--teardown)))
+
+(ert-deftest test-mc-playlist-reload-error-no-associated-file ()
+  "Error: no associated playlist file -> assert step errors with user-error."
+  (test-mc-pc--setup)
+  (unwind-protect
+      (with-current-buffer cj/music-playlist-buffer-name
+        (setq cj/music-playlist-file nil)
+        (should-error (cj/music-playlist-reload) :type 'user-error))
+    (test-mc-pc--teardown)))
+
+;;; cj/music-playlist-edit
+
+(ert-deftest test-mc-playlist-edit-opens-other-window-when-clean ()
+  "Normal: with a clean playlist, edit opens the file in another window."
+  (test-mc-pc--setup)
+  (unwind-protect
+      (let ((tmp (make-temp-file "test-mc-edit-" nil ".m3u"))
+            (opened nil))
+        (with-temp-file tmp (insert "track.mp3\n"))
+        (with-current-buffer cj/music-playlist-buffer-name
+          (setq cj/music-playlist-file tmp))
+        (cl-letf (((symbol-function 'cj/music--playlist-modified-p)
+                   (lambda () nil))
+                  ((symbol-function 'find-file-other-window)
+                   (lambda (p) (setq opened p))))
+          (cj/music-playlist-edit))
+        (should (equal opened tmp))
+        (delete-file tmp))
+    (test-mc-pc--teardown)))
+
+;;; cj/music-next / cj/music-previous
+
+(ert-deftest test-mc-next-uses-emms-next-when-not-random ()
+  "Normal: with random off, next delegates to emms-next."
+  (let ((emms-random-playlist nil)
+        (called nil))
+    (cl-letf (((symbol-function 'emms-next)
+               (lambda () (setq called 'next)))
+              ((symbol-function 'emms-random)
+               (lambda () (setq called 'random))))
+      (cj/music-next))
+    (should (eq called 'next))))
+
+(ert-deftest test-mc-next-uses-emms-random-when-random-on ()
+  "Normal: with random on, next picks a random track."
+  (let ((emms-random-playlist t)
+        (called nil))
+    (cl-letf (((symbol-function 'emms-next)
+               (lambda () (setq called 'next)))
+              ((symbol-function 'emms-random)
+               (lambda () (setq called 'random))))
+      (cj/music-next))
+    (should (eq called 'random))))
+
+(ert-deftest test-mc-previous-uses-emms-previous-when-not-random ()
+  "Normal: with random off, previous delegates to emms-previous."
+  (let ((emms-random-playlist nil)
+        (called nil))
+    (cl-letf (((symbol-function 'emms-previous)
+               (lambda () (setq called 'prev))))
+      (cj/music-previous))
+    (should (eq called 'prev))))
+
+(ert-deftest test-mc-previous-empty-random-history-messages-and-delegates ()
+  "Boundary: random on but no history -> message + delegate to emms-previous."
+  (let ((emms-random-playlist t)
+        (cj/music--random-history nil)
+        (called nil)
+        (msg nil))
+    (cl-letf (((symbol-function 'emms-previous)
+               (lambda () (setq called 'prev)))
+              ((symbol-function 'message)
+               (lambda (fmt &rest args) (setq msg (apply #'format fmt args)))))
+      (cj/music-previous))
+    (should (eq called 'prev))
+    (should (string-match-p "No random history" msg))))
+
+(ert-deftest test-mc-previous-random-history-jumps-to-popped-track ()
+  "Normal: random with history -> pop name, find pos, emms-playlist-select + start."
+  (test-mc-pc--setup)
+  (unwind-protect
+      (let ((emms-random-playlist t)
+            (cj/music--random-history '("/a/track-2.mp3" "/a/track-1.mp3"))
+            (selected nil)
+            (started nil))
+        (cl-letf (((symbol-function 'cj/music--find-track-in-playlist)
+                   (lambda (name) (when (equal name "/a/track-2.mp3") 42)))
+                  ((symbol-function 'emms-playlist-select)
+                   (lambda (pos) (setq selected pos)))
+                  ((symbol-function 'emms-start)
+                   (lambda () (setq started t))))
+          (cj/music-previous))
+        (should (= selected 42))
+        (should started)
+        ;; Top of history was consumed.
+        (should (equal cj/music--random-history '("/a/track-1.mp3"))))
+    (test-mc-pc--teardown)))
+
+(ert-deftest test-mc-previous-random-popped-track-missing-messages ()
+  "Boundary: history pop returns a track no longer in the playlist -> message."
+  (test-mc-pc--setup)
+  (unwind-protect
+      (let ((emms-random-playlist t)
+            (cj/music--random-history '("/a/gone.mp3"))
+            (started nil)
+            (msg nil))
+        (cl-letf (((symbol-function 'cj/music--find-track-in-playlist)
+                   (lambda (_) nil))
+                  ((symbol-function 'emms-start)
+                   (lambda () (setq started t)))
+                  ((symbol-function 'message)
+                   (lambda (fmt &rest args)
+                     (setq msg (apply #'format fmt args)))))
+          (cj/music-previous))
+        (should-not started)
+        (should (string-match-p "no longer in playlist" msg)))
+    (test-mc-pc--teardown)))
+
+;;; cj/music--consume-track
+
+(ert-deftest test-mc-consume-track-no-op-when-mode-off ()
+  "Boundary: with consume-mode off, the function doesn't touch the playlist."
+  (test-mc-pc--setup)
+  (unwind-protect
+      (let ((cj/music-consume-mode nil)
+            (killed nil))
+        (cl-letf (((symbol-function 'emms-playlist-mode-kill-track)
+                   (lambda () (setq killed t))))
+          (cj/music--consume-track))
+        (should-not killed))
+    (test-mc-pc--teardown)))
+
+(ert-deftest test-mc-consume-track-kills-selected-when-mode-on ()
+  "Normal: with consume on + a live selected marker, kill-track is called."
+  (test-mc-pc--setup)
+  (unwind-protect
+      (let ((cj/music-consume-mode t)
+            (killed nil))
+        (with-current-buffer cj/music-playlist-buffer-name
+          (let ((inhibit-read-only t))
+            (erase-buffer)
+            (insert "track\n"))
+          (setq emms-playlist-selected-marker (point-min-marker)))
+        (cl-letf (((symbol-function 'emms-playlist-mode-kill-track)
+                   (lambda () (setq killed t))))
+          (cj/music--consume-track))
+        (should killed))
+    (test-mc-pc--teardown)))
+
+(provide 'test-music-config-playlist-commands)
+;;; test-music-config-playlist-commands.el ends here