feat(recording): validate system audio device before recording

Add pre-recording validation that catches stale or drifted system audio
devices before they cause silent recordings. When the default audio
output changes (Bluetooth reconnect, device switch) between setup and
recording, the monitor device is auto-updated. Warns if no audio is
currently playing through the monitored sink.

Co-Authored-By: Craig Jennings <c@cjennings.net>

1 files changed, 162 insertions, 0 deletions

diff --git a/tests/test-video-audio-recording-validate-system-audio.el b/tests/test-video-audio-recording-validate-system-audio.el
new file mode 100644
index 00000000..ef730ab3
--- /dev/null
+++ b/tests/test-video-audio-recording-validate-system-audio.el
@@ -0,0 +1,162 @@
+;;; test-video-audio-recording-validate-system-audio.el --- Tests for cj/recording--validate-system-audio -*- lexical-binding: t; -*-
+
+;;; Commentary:
+;; Unit tests for cj/recording--validate-system-audio function.
+;; Tests the pre-recording validation that catches stale/drifted system
+;; audio devices before they cause silent recordings.
+
+;;; Code:
+
+(require 'ert)
+
+;; Stub dependencies before loading the module
+(defvar cj/custom-keymap (make-sparse-keymap)
+  "Stub keymap for testing.")
+
+(require 'video-audio-recording)
+
+;;; Setup and Teardown
+
+(defun test-validate-setup ()
+  "Reset device variables before each test."
+  (setq cj/recording-system-device nil))
+
+(defun test-validate-teardown ()
+  "Clean up device variables after each test."
+  (setq cj/recording-system-device nil))
+
+;;; Normal Cases
+
+(ert-deftest test-validate-system-audio-normal-device-matches-default-no-change ()
+  "Test that no change occurs when device matches current default and audio is active."
+  (test-validate-setup)
+  (unwind-protect
+      (let ((cj/recording-system-device "alsa_output.usb-Jabra-00.analog-stereo.monitor"))
+        (cl-letf (((symbol-function 'shell-command-to-string)
+                   (lambda (cmd)
+                     (cond
+                      ((string-match-p "sources short" cmd)
+                       "65\talsa_output.usb-Jabra-00.analog-stereo.monitor\tPipeWire\ts32le 2ch 48000Hz\tSUSPENDED\n")
+                      ((string-match-p "sinks short" cmd)
+                       "65\talsa_output.usb-Jabra-00.analog-stereo\tPipeWire\ts32le 2ch 48000Hz\tSUSPENDED\n")
+                      ((string-match-p "sink-inputs" cmd) "Sink Input #1\n\tSink: 65\n")
+                      ((string-match-p "get-default-sink" cmd) "alsa_output.usb-Jabra-00.analog-stereo")
+                      (t "")))))
+          (cj/recording--validate-system-audio)
+          (should (equal "alsa_output.usb-Jabra-00.analog-stereo.monitor"
+                         cj/recording-system-device))))
+    (test-validate-teardown)))
+
+(ert-deftest test-validate-system-audio-normal-stale-device-auto-updates ()
+  "Test that a stale (non-existent) device is auto-updated to current default."
+  (test-validate-setup)
+  (unwind-protect
+      (let ((cj/recording-system-device "old_disappeared_device.monitor")
+            (messages nil))
+        (cl-letf (((symbol-function 'shell-command-to-string)
+                   (lambda (cmd)
+                     (cond
+                      ((string-match-p "sources short" cmd)
+                       ;; Old device NOT in list
+                       "65\talsa_output.usb-Jabra-00.analog-stereo.monitor\tPipeWire\ts32le 2ch 48000Hz\tSUSPENDED\n")
+                      ((string-match-p "sinks short" cmd)
+                       "65\talsa_output.usb-Jabra-00.analog-stereo\tPipeWire\ts32le 2ch 48000Hz\tSUSPENDED\n")
+                      ((string-match-p "sink-inputs" cmd) "Sink Input #1\n\tSink: 65\n")
+                      ((string-match-p "get-default-sink" cmd) "alsa_output.usb-Jabra-00.analog-stereo")
+                      (t ""))))
+                  ((symbol-function 'message)
+                   (lambda (fmt &rest args)
+                     (push (apply #'format fmt args) messages))))
+          (cj/recording--validate-system-audio)
+          (should (equal "alsa_output.usb-Jabra-00.analog-stereo.monitor"
+                         cj/recording-system-device))
+          (should (cl-some (lambda (m) (string-match-p "no longer exists" m)) messages))))
+    (test-validate-teardown)))
+
+(ert-deftest test-validate-system-audio-normal-drifted-default-auto-updates ()
+  "Test that device is updated when default sink has drifted."
+  (test-validate-setup)
+  (unwind-protect
+      (let ((cj/recording-system-device "alsa_output.pci-0000.hdmi-stereo.monitor")
+            (messages nil))
+        (cl-letf (((symbol-function 'shell-command-to-string)
+                   (lambda (cmd)
+                     (cond
+                      ((string-match-p "sources short" cmd)
+                       ;; Old device still exists
+                       (concat "65\talsa_output.pci-0000.hdmi-stereo.monitor\tPipeWire\ts32le 2ch 48000Hz\tSUSPENDED\n"
+                               "69\talsa_output.usb-Jabra-00.analog-stereo.monitor\tPipeWire\ts32le 2ch 48000Hz\tSUSPENDED\n"))
+                      ((string-match-p "sinks short" cmd)
+                       "69\talsa_output.usb-Jabra-00.analog-stereo\tPipeWire\ts32le 2ch 48000Hz\tSUSPENDED\n")
+                      ((string-match-p "sink-inputs" cmd) "Sink Input #1\n\tSink: 69\n")
+                      ;; But default has changed to Jabra
+                      ((string-match-p "get-default-sink" cmd) "alsa_output.usb-Jabra-00.analog-stereo")
+                      (t ""))))
+                  ((symbol-function 'message)
+                   (lambda (fmt &rest args)
+                     (push (apply #'format fmt args) messages))))
+          (cj/recording--validate-system-audio)
+          (should (equal "alsa_output.usb-Jabra-00.analog-stereo.monitor"
+                         cj/recording-system-device))
+          (should (cl-some (lambda (m) (string-match-p "default output changed" m)) messages))))
+    (test-validate-teardown)))
+
+(ert-deftest test-validate-system-audio-normal-no-audio-warns ()
+  "Test that no active audio triggers a y-or-n-p warning."
+  (test-validate-setup)
+  (unwind-protect
+      (let ((cj/recording-system-device "alsa_output.usb-Jabra-00.analog-stereo.monitor")
+            (prompted nil))
+        (cl-letf (((symbol-function 'shell-command-to-string)
+                   (lambda (cmd)
+                     (cond
+                      ((string-match-p "sources short" cmd)
+                       "65\talsa_output.usb-Jabra-00.analog-stereo.monitor\tPipeWire\ts32le 2ch 48000Hz\tSUSPENDED\n")
+                      ((string-match-p "sinks short" cmd)
+                       "65\talsa_output.usb-Jabra-00.analog-stereo\tPipeWire\ts32le 2ch 48000Hz\tSUSPENDED\n")
+                      ;; No sink inputs — nothing playing
+                      ((string-match-p "sink-inputs" cmd) "")
+                      ((string-match-p "get-default-sink" cmd) "alsa_output.usb-Jabra-00.analog-stereo")
+                      (t ""))))
+                  ((symbol-function 'y-or-n-p)
+                   (lambda (prompt)
+                     (setq prompted prompt)
+                     t)))  ; User says yes, continue
+          (cj/recording--validate-system-audio)
+          (should prompted)
+          (should (string-match-p "No audio is playing" prompted))))
+    (test-validate-teardown)))
+
+(ert-deftest test-validate-system-audio-normal-no-audio-user-cancels ()
+  "Test that user declining the warning cancels recording."
+  (test-validate-setup)
+  (unwind-protect
+      (let ((cj/recording-system-device "alsa_output.usb-Jabra-00.analog-stereo.monitor"))
+        (cl-letf (((symbol-function 'shell-command-to-string)
+                   (lambda (cmd)
+                     (cond
+                      ((string-match-p "sources short" cmd)
+                       "65\talsa_output.usb-Jabra-00.analog-stereo.monitor\tPipeWire\ts32le 2ch 48000Hz\tSUSPENDED\n")
+                      ((string-match-p "sinks short" cmd)
+                       "65\talsa_output.usb-Jabra-00.analog-stereo\tPipeWire\ts32le 2ch 48000Hz\tSUSPENDED\n")
+                      ((string-match-p "sink-inputs" cmd) "")
+                      ((string-match-p "get-default-sink" cmd) "alsa_output.usb-Jabra-00.analog-stereo")
+                      (t ""))))
+                  ((symbol-function 'y-or-n-p)
+                   (lambda (_prompt) nil)))  ; User says no
+          (should-error (cj/recording--validate-system-audio) :type 'user-error)))
+    (test-validate-teardown)))
+
+;;; Boundary Cases
+
+(ert-deftest test-validate-system-audio-boundary-nil-device-skips-validation ()
+  "Test that nil system device skips all validation."
+  (let ((cj/recording-system-device nil)
+        (shell-called nil))
+    (cl-letf (((symbol-function 'shell-command-to-string)
+               (lambda (_cmd) (setq shell-called t) "")))
+      (cj/recording--validate-system-audio)
+      (should-not shell-called))))
+
+(provide 'test-video-audio-recording-validate-system-audio)
+;;; test-video-audio-recording-validate-system-audio.el ends here