From 3bc33fc34cf8f6dd70b683da55208613f2ba7271 Mon Sep 17 00:00:00 2001
From: Mathias <mthbqv@gmail.com>
Date: Thu, 1 Oct 2026 16:46:14 +0200
Subject: [PATCH] test(audio): ffmpeg transcode to 16 kHz mono PCM, always
 (red)

Red: audio.FFmpeg is undefined.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
---
 internal/adapters/audio/ffmpeg_test.go | 58 ++++++++++++++++++++++++++
 1 file changed, 58 insertions(+)
 create mode 100644 internal/adapters/audio/ffmpeg_test.go

diff --git a/internal/adapters/audio/ffmpeg_test.go b/internal/adapters/audio/ffmpeg_test.go
new file mode 100644
index 0000000..1aaf6d1
--- /dev/null
+++ b/internal/adapters/audio/ffmpeg_test.go
@@ -0,0 +1,58 @@
+package audio_test
+
+import (
+	"context"
+	"errors"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"git.d-ma.be/mathias/tapir/internal/adapters/audio"
+)
+
+func TestFFmpegToWAV_AsksForSixteenKilohertzMonoPCMAlways(t *testing.T) {
+	// Always transcode, even when the input already is 16 kHz mono: a Teams export
+	// often is, and the point is to not ASSUME (ADR-033). Records the argv.
+	rec := filepath.Join(t.TempDir(), "argv")
+	bin := stub(t, `printf '%s\n' "$@" > `+rec+`; : > "$(eval echo \${$#})"`)
+
+	err := (&audio.FFmpeg{Bin: bin}).ToWAV(context.Background(), "/spool/in", filepath.Join(t.TempDir(), "out.wav"))
+
+	require.NoError(t, err)
+	raw, err := os.ReadFile(rec)
+	require.NoError(t, err)
+	argv := strings.Split(strings.TrimSpace(string(raw)), "\n")
+	joined := " " + strings.Join(argv, " ") + " "
+	for _, want := range []string{" -ac 1 ", " -ar 16000 ", " -c:a pcm_s16le ", " -vn ", " -i /spool/in "} {
+		assert.Contains(t, joined, want)
+	}
+	assert.True(t, strings.HasSuffix(strings.TrimSpace(joined), "out.wav"), "the output path is the last argument")
+}
+
+func TestFFmpegToWAV_NonzeroExitIsAnErrorCarryingStderr(t *testing.T) {
+	bin := stub(t, `echo "moov atom not found" >&2; exit 1`)
+
+	err := (&audio.FFmpeg{Bin: bin}).ToWAV(context.Background(), "/in", filepath.Join(t.TempDir(), "o.wav"))
+
+	require.Error(t, err)
+	assert.Contains(t, err.Error(), "moov atom not found")
+}
+
+func TestFFmpegToWAV_ZeroExitWithNoOutputIsAnError(t *testing.T) {
+	bin := stub(t, `exit 0`)
+
+	err := (&audio.FFmpeg{Bin: bin}).ToWAV(context.Background(), "/in", filepath.Join(t.TempDir(), "never-written.wav"))
+
+	require.Error(t, err)
+}
+
+func TestFFmpegToWAV_MissingBinaryIsAnError(t *testing.T) {
+	err := (&audio.FFmpeg{Bin: filepath.Join(t.TempDir(), "no-ffmpeg")}).ToWAV(context.Background(), "/in", "/out.wav")
+
+	require.Error(t, err)
+	assert.False(t, errors.Is(err, context.Canceled))
+}