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, 91 insertions, 0 deletions

diff --git a/tests/test-video-audio-recording--sink-has-active-audio-p.el b/tests/test-video-audio-recording--sink-has-active-audio-p.el
new file mode 100644
index 00000000..eab0745a
--- /dev/null
+++ b/tests/test-video-audio-recording--sink-has-active-audio-p.el
@@ -0,0 +1,91 @@
+;;; test-video-audio-recording--sink-has-active-audio-p.el --- Tests for cj/recording--sink-has-active-audio-p -*- lexical-binding: t; -*-
+
+;;; Commentary:
+;; Unit tests for cj/recording--sink-has-active-audio-p function.
+;; Tests parsing of pactl sink-inputs output to detect active audio streams.
+
+;;; Code:
+
+(require 'ert)
+
+;; Stub dependencies before loading the module
+(defvar cj/custom-keymap (make-sparse-keymap)
+  "Stub keymap for testing.")
+
+(require 'video-audio-recording)
+
+;;; Test Fixtures Helper
+
+(defun test-load-fixture (filename)
+  "Load fixture file FILENAME from tests/fixtures directory."
+  (let ((fixture-path (expand-file-name
+                       (concat "tests/fixtures/" filename)
+                       user-emacs-directory)))
+    (with-temp-buffer
+      (insert-file-contents fixture-path)
+      (buffer-string))))
+
+;;; Normal Cases
+
+(ert-deftest test-sink-has-active-audio-p-normal-active-sink-returns-t ()
+  "Test that active audio on our sink returns non-nil."
+  (let ((output (test-load-fixture "pactl-sink-inputs-active.txt")))
+    (should (cj/recording--sink-has-active-audio-p "65" output))))
+
+(ert-deftest test-sink-has-active-audio-p-normal-different-sink-returns-nil ()
+  "Test that audio on a different sink returns nil."
+  (let ((output (test-load-fixture "pactl-sink-inputs-different-sink.txt")))
+    (should-not (cj/recording--sink-has-active-audio-p "65" output))))
+
+;;; Boundary Cases
+
+(ert-deftest test-sink-has-active-audio-p-boundary-empty-output-returns-nil ()
+  "Test that empty pactl output returns nil."
+  (should-not (cj/recording--sink-has-active-audio-p "65" "")))
+
+(ert-deftest test-sink-has-active-audio-p-boundary-no-sink-inputs-returns-nil ()
+  "Test that output with no sink inputs returns nil."
+  (let ((output (test-load-fixture "pactl-sink-inputs-empty.txt")))
+    (should-not (cj/recording--sink-has-active-audio-p "65" output))))
+
+(ert-deftest test-sink-has-active-audio-p-boundary-multiple-inputs-one-matches ()
+  "Test that multiple sink inputs where one matches returns non-nil."
+  (let ((output (concat "Sink Input #42\n"
+                        "\tSink: 73\n"
+                        "\tCorked: no\n"
+                        "Sink Input #43\n"
+                        "\tSink: 65\n"
+                        "\tCorked: no\n")))
+    (should (cj/recording--sink-has-active-audio-p "65" output))))
+
+(ert-deftest test-sink-has-active-audio-p-boundary-index-substring-no-false-match ()
+  "Test that sink index 6 does not match sink 65."
+  (let ((output (test-load-fixture "pactl-sink-inputs-active.txt")))
+    (should-not (cj/recording--sink-has-active-audio-p "6" output))))
+
+;;; get-sink-index tests
+
+(ert-deftest test-get-sink-index-normal-returns-index ()
+  "Test that sink name is resolved to its index."
+  (let ((output "65\talsa_output.usb-Jabra-00.analog-stereo\tPipeWire\ts32le 2ch 48000Hz\tSUSPENDED\n"))
+    (should (equal "65" (cj/recording--get-sink-index
+                         "alsa_output.usb-Jabra-00.analog-stereo" output)))))
+
+(ert-deftest test-get-sink-index-normal-nonexistent-returns-nil ()
+  "Test that non-existent sink name returns nil."
+  (let ((output "65\talsa_output.usb-Jabra-00.analog-stereo\tPipeWire\ts32le 2ch 48000Hz\tSUSPENDED\n"))
+    (should-not (cj/recording--get-sink-index "nonexistent-sink" output))))
+
+(ert-deftest test-get-sink-index-boundary-empty-output-returns-nil ()
+  "Test that empty output returns nil."
+  (should-not (cj/recording--get-sink-index "any-sink" "")))
+
+(ert-deftest test-get-sink-index-normal-multiple-sinks ()
+  "Test correct index returned when multiple sinks present."
+  (let ((output (concat "65\talsa_output.pci-0000.hdmi-stereo\tPipeWire\ts32le 2ch 48000Hz\tSUSPENDED\n"
+                        "69\talsa_output.usb-Jabra-00.analog-stereo\tPipeWire\ts32le 2ch 48000Hz\tSUSPENDED\n")))
+    (should (equal "69" (cj/recording--get-sink-index
+                         "alsa_output.usb-Jabra-00.analog-stereo" output)))))
+
+(provide 'test-video-audio-recording--sink-has-active-audio-p)
+;;; test-video-audio-recording--sink-has-active-audio-p.el ends here