test: Add comprehensive test suite for video-audio-recording module

Added 83 test cases across 9 test files with 100% pass rate, covering
device detection, parsing, grouping, and complete workflow integration.

## What Was Done

### Refactoring for Testability
- Extracted `cj/recording--parse-pactl-output` from `cj/recording-parse-sources`
- Separated parsing logic from shell command execution
- Enables testing with fixture data instead of live system calls

### Test Fixtures Created
- `pactl-output-normal.txt` - All device types (built-in, USB, Bluetooth)
- `pactl-output-empty.txt` - Empty output
- `pactl-output-single.txt` - Single device
- `pactl-output-monitors-only.txt` - Only monitor devices
- `pactl-output-inputs-only.txt` - Only input devices
- `pactl-output-malformed.txt` - Invalid/malformed output

### Unit Tests (8 files, 78 test cases)
1. **test-video-audio-recording-friendly-state.el** (10 tests)
   - State name conversion: SUSPENDED→Ready, RUNNING→Active

2. **test-video-audio-recording-parse-pactl-output.el** (14 tests)
   - Parse raw pactl output into structured data
   - Handle empty, malformed, and mixed valid/invalid input

3. **test-video-audio-recording-parse-sources.el** (6 tests)
   - Shell command wrapper testing with mocked output

4. **test-video-audio-recording-detect-mic-device.el** (13 tests)
   - Documents bugs: Returns ID numbers instead of device names
   - Doesn't filter monitors (legacy function, not actively used)

5. **test-video-audio-recording-detect-system-device.el** (13 tests)
   - Works correctly: Returns full device names
   - Tests monitor detection with various device types

6. **test-video-audio-recording-group-devices-by-hardware.el** (12 tests)
   - CRITICAL: Bluetooth MAC address normalization (colons vs underscores)
   - Device pairing logic (mic + monitor from same hardware)
   - Friendly name assignment
   - Filters incomplete devices

7. **test-video-audio-recording-check-ffmpeg.el** (3 tests)
   - ffmpeg availability detection

8. **test-video-audio-recording-get-devices.el** (7 tests)
   - Auto-detection fallback logic
   - Error handling for incomplete detection

### Integration Tests (1 file, 5 test cases)
9. **test-integration-recording-device-workflow.el** (5 tests)
   - Complete workflow: parse → group → friendly names
   - Bluetooth MAC normalization end-to-end
   - Incomplete device filtering across components
   - Malformed data graceful handling

## Key Testing Insights

### Bugs Documented
- `cj/recording-detect-mic-device` has bugs (returns IDs, doesn't filter monitors)
- These functions appear to be legacy code not used by main workflow
- Tests document current behavior to catch regressions if fixed

### Critical Features Validated
- **Bluetooth MAC normalization**: Input uses colons (00:1B:66:C0:91:6D),
  output uses underscores (00_1B_66_C0_91_6D), grouping normalizes correctly
- **Device pairing**: Only devices with BOTH mic and monitor are included
- **Friendly names**: USB/PCI/Bluetooth patterns correctly identified

### Test Coverage
- Normal cases: Valid inputs, typical workflows
- Boundary cases: Empty, single device, incomplete pairs
- Error cases: Malformed input, missing devices, partial detection

## Test Execution
All tests pass: 9/9 files, 83/83 test cases (100% pass rate)

```bash
make test-file FILE=test-video-audio-recording-*.el
# All pass individually

# Integration test also passes
make test-file FILE=test-integration-recording-device-workflow.el
```

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

1 files changed, 194 insertions, 0 deletions

diff --git a/tests/test-video-audio-recording-group-devices-by-hardware.el b/tests/test-video-audio-recording-group-devices-by-hardware.el
new file mode 100644
index 00000000..0abe5f6c
--- /dev/null
+++ b/tests/test-video-audio-recording-group-devices-by-hardware.el
@@ -0,0 +1,194 @@
+;;; test-video-audio-recording-group-devices-by-hardware.el --- Tests for cj/recording-group-devices-by-hardware -*- lexical-binding: t; -*-
+
+;;; Commentary:
+;; Unit tests for cj/recording-group-devices-by-hardware function.
+;; Tests grouping of audio sources by physical hardware device.
+;; Critical test: Bluetooth MAC address normalization (colons vs underscores).
+;;
+;; This function is used by the quick setup command to automatically pair
+;; microphone and monitor devices from the same hardware.
+
+;;; Code:
+
+(require 'ert)
+
+;; Stub dependencies before loading the module
+(defvar cj/custom-keymap (make-sparse-keymap)
+  "Stub keymap for testing.")
+
+;; Now load the actual production module
+(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-video-audio-recording-group-devices-by-hardware-normal-all-types-grouped ()
+  "Test grouping of all three device types (built-in, USB, Bluetooth).
+This is the key test validating the complete grouping logic."
+  (let ((output (test-load-fixture "pactl-output-normal.txt")))
+    (cl-letf (((symbol-function 'shell-command-to-string)
+               (lambda (_cmd) output)))
+      (let ((result (cj/recording-group-devices-by-hardware)))
+        (should (listp result))
+        (should (= 3 (length result)))
+        ;; Check that we have all three device types
+        (let ((names (mapcar #'car result)))
+          (should (member "Built-in Laptop Audio" names))
+          (should (member "Bluetooth Headset" names))
+          (should (member "Jabra SPEAK 510 USB" names)))
+        ;; Verify each device has both mic and monitor
+        (dolist (device result)
+          (should (stringp (car device)))           ; friendly name
+          (should (stringp (cadr device)))          ; mic device
+          (should (stringp (cddr device)))          ; monitor device
+          (should-not (string-suffix-p ".monitor" (cadr device)))  ; mic not monitor
+          (should (string-suffix-p ".monitor" (cddr device))))))))  ; monitor has suffix
+
+(ert-deftest test-video-audio-recording-group-devices-by-hardware-normal-built-in-paired ()
+  "Test that built-in laptop audio devices are correctly paired."
+  (let ((output (test-load-fixture "pactl-output-normal.txt")))
+    (cl-letf (((symbol-function 'shell-command-to-string)
+               (lambda (_cmd) output)))
+      (let* ((result (cj/recording-group-devices-by-hardware))
+             (built-in (assoc "Built-in Laptop Audio" result)))
+        (should built-in)
+        (should (string-match-p "pci-0000_00_1f" (cadr built-in)))
+        (should (string-match-p "pci-0000_00_1f" (cddr built-in)))
+        (should (equal "alsa_input.pci-0000_00_1f.3.analog-stereo" (cadr built-in)))
+        (should (equal "alsa_output.pci-0000_00_1f.3.analog-stereo.monitor" (cddr built-in)))))))
+
+(ert-deftest test-video-audio-recording-group-devices-by-hardware-normal-usb-paired ()
+  "Test that USB devices (Jabra) are correctly paired."
+  (let ((output (test-load-fixture "pactl-output-normal.txt")))
+    (cl-letf (((symbol-function 'shell-command-to-string)
+               (lambda (_cmd) output)))
+      (let* ((result (cj/recording-group-devices-by-hardware))
+             (jabra (assoc "Jabra SPEAK 510 USB" result)))
+        (should jabra)
+        (should (string-match-p "Jabra" (cadr jabra)))
+        (should (string-match-p "Jabra" (cddr jabra)))))))
+
+(ert-deftest test-video-audio-recording-group-devices-by-hardware-normal-bluetooth-paired ()
+  "Test that Bluetooth devices are correctly paired.
+CRITICAL: Tests MAC address normalization (colons in input, underscores in output)."
+  (let ((output (test-load-fixture "pactl-output-normal.txt")))
+    (cl-letf (((symbol-function 'shell-command-to-string)
+               (lambda (_cmd) output)))
+      (let* ((result (cj/recording-group-devices-by-hardware))
+             (bluetooth (assoc "Bluetooth Headset" result)))
+        (should bluetooth)
+        ;; Input has colons: bluez_input.00:1B:66:C0:91:6D
+        (should (equal "bluez_input.00:1B:66:C0:91:6D" (cadr bluetooth)))
+        ;; Output has underscores: bluez_output.00_1B_66_C0_91_6D.1.monitor
+        ;; But they should still be grouped together (MAC address normalized)
+        (should (equal "bluez_output.00_1B_66_C0_91_6D.1.monitor" (cddr bluetooth)))))))
+
+;;; Boundary Cases
+
+(ert-deftest test-video-audio-recording-group-devices-by-hardware-boundary-empty-returns-empty ()
+  "Test that empty pactl output returns empty list."
+  (cl-letf (((symbol-function 'shell-command-to-string)
+             (lambda (_cmd) "")))
+    (let ((result (cj/recording-group-devices-by-hardware)))
+      (should (listp result))
+      (should (null result)))))
+
+(ert-deftest test-video-audio-recording-group-devices-by-hardware-boundary-only-inputs-returns-empty ()
+  "Test that only input devices (no monitors) returns empty list.
+Devices must have BOTH mic and monitor to be included."
+  (let ((output (test-load-fixture "pactl-output-inputs-only.txt")))
+    (cl-letf (((symbol-function 'shell-command-to-string)
+               (lambda (_cmd) output)))
+      (let ((result (cj/recording-group-devices-by-hardware)))
+        (should (listp result))
+        (should (null result))))))
+
+(ert-deftest test-video-audio-recording-group-devices-by-hardware-boundary-only-monitors-returns-empty ()
+  "Test that only monitor devices (no inputs) returns empty list."
+  (let ((output (test-load-fixture "pactl-output-monitors-only.txt")))
+    (cl-letf (((symbol-function 'shell-command-to-string)
+               (lambda (_cmd) output)))
+      (let ((result (cj/recording-group-devices-by-hardware)))
+        (should (listp result))
+        (should (null result))))))
+
+(ert-deftest test-video-audio-recording-group-devices-by-hardware-boundary-single-complete-device ()
+  "Test that single device with both mic and monitor is returned."
+  (let ((output "50\talsa_input.pci-0000_00_1f.3.analog-stereo\tPipeWire\ts32le 2ch 48000Hz\tSUSPENDED\n49\talsa_output.pci-0000_00_1f.3.analog-stereo.monitor\tPipeWire\ts32le 2ch 48000Hz\tSUSPENDED\n"))
+    (cl-letf (((symbol-function 'shell-command-to-string)
+               (lambda (_cmd) output)))
+      (let ((result (cj/recording-group-devices-by-hardware)))
+        (should (= 1 (length result)))
+        (should (equal "Built-in Laptop Audio" (caar result)))))))
+
+(ert-deftest test-video-audio-recording-group-devices-by-hardware-boundary-mixed-complete-incomplete ()
+  "Test that only devices with BOTH mic and monitor are included.
+Incomplete devices (only mic or only monitor) are filtered out."
+  (let ((output (concat
+                 ;; Complete device (built-in)
+                 "50\talsa_input.pci-0000_00_1f.3.analog-stereo\tPipeWire\ts32le 2ch 48000Hz\tSUSPENDED\n"
+                 "49\talsa_output.pci-0000_00_1f.3.analog-stereo.monitor\tPipeWire\ts32le 2ch 48000Hz\tSUSPENDED\n"
+                 ;; Incomplete: USB mic with no monitor
+                 "100\talsa_input.usb-device.mono-fallback\tPipeWire\ts16le 1ch 16000Hz\tSUSPENDED\n"
+                 ;; Incomplete: Bluetooth monitor with no mic
+                 "81\tbluez_output.AA_BB_CC_DD_EE_FF.1.monitor\tPipeWire\ts24le 2ch 48000Hz\tRUNNING\n")))
+    (cl-letf (((symbol-function 'shell-command-to-string)
+               (lambda (_cmd) output)))
+      (let ((result (cj/recording-group-devices-by-hardware)))
+        ;; Only the complete built-in device should be returned
+        (should (= 1 (length result)))
+        (should (equal "Built-in Laptop Audio" (caar result)))))))
+
+;;; Error Cases
+
+(ert-deftest test-video-audio-recording-group-devices-by-hardware-error-malformed-output-returns-empty ()
+  "Test that malformed pactl output returns empty list."
+  (let ((output (test-load-fixture "pactl-output-malformed.txt")))
+    (cl-letf (((symbol-function 'shell-command-to-string)
+               (lambda (_cmd) output)))
+      (let ((result (cj/recording-group-devices-by-hardware)))
+        (should (listp result))
+        (should (null result))))))
+
+(ert-deftest test-video-audio-recording-group-devices-by-hardware-error-unknown-device-type ()
+  "Test that unknown device types get generic 'USB Audio Device' name."
+  (let ((output (concat
+                 "100\talsa_input.usb-unknown_device-00.analog-stereo\tPipeWire\ts16le 2ch 16000Hz\tSUSPENDED\n"
+                 "99\talsa_output.usb-unknown_device-00.analog-stereo.monitor\tPipeWire\ts16le 2ch 48000Hz\tSUSPENDED\n")))
+    (cl-letf (((symbol-function 'shell-command-to-string)
+               (lambda (_cmd) output)))
+      (let ((result (cj/recording-group-devices-by-hardware)))
+        (should (= 1 (length result)))
+        ;; Should get generic USB name (not matching Jabra pattern)
+        (should (equal "USB Audio Device" (caar result)))))))
+
+(ert-deftest test-video-audio-recording-group-devices-by-hardware-error-bluetooth-mac-case-variations ()
+  "Test that Bluetooth MAC addresses work with different formatting.
+Tests the normalization logic handles various MAC address formats."
+  (let ((output (concat
+                 ;; Input with colons (typical)
+                 "79\tbluez_input.AA:BB:CC:DD:EE:FF\tPipeWire\tfloat32le 1ch 48000Hz\tSUSPENDED\n"
+                 ;; Output with underscores (typical)
+                 "81\tbluez_output.AA_BB_CC_DD_EE_FF.1.monitor\tPipeWire\ts24le 2ch 48000Hz\tRUNNING\n")))
+    (cl-letf (((symbol-function 'shell-command-to-string)
+               (lambda (_cmd) output)))
+      (let ((result (cj/recording-group-devices-by-hardware)))
+        (should (= 1 (length result)))
+        (should (equal "Bluetooth Headset" (caar result)))
+        ;; Verify both devices paired despite different MAC formats
+        (let ((device (car result)))
+          (should (string-match-p "AA:BB:CC" (cadr device)))
+          (should (string-match-p "AA_BB_CC" (cddr device))))))))
+
+(provide 'test-video-audio-recording-group-devices-by-hardware)
+;;; test-video-audio-recording-group-devices-by-hardware.el ends here