add WhisperCppAdapter for local whisper-cpp transcription

internal/transcriber/adapter_whisper_cpp_test.go

@@ -0,0 +1,125 @@
+package transcriber
+
+import (
+	"context"
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+func TestWhisperCppAdapter_ImplementsBatchAdapter(t *testing.T) {
+	// compile-time check that WhisperCppAdapter implements BatchAdapter
+	var _ BatchAdapter = (*WhisperCppAdapter)(nil)
+}
+
+func TestWhisperCppAdapter_EmptyAudio(t *testing.T) {
+	adapter := NewWhisperCppAdapter("/nonexistent/model.bin", "en", 4)
+	text, err := adapter.Transcribe(context.Background(), []byte{})
+	if err != nil {
+		t.Errorf("expected no error for empty audio, got: %v", err)
+	}
+	if text != "" {
+		t.Errorf("expected empty text for empty audio, got: %q", text)
+	}
+}
+
+func TestWhisperCppAdapter_MissingModel(t *testing.T) {
+	adapter := NewWhisperCppAdapter("/nonexistent/path/model.bin", "en", 4)
+
+	// create minimal valid PCM data (just zeros)
+	audioData := make([]byte, 32000) // 1 second at 16kHz 16-bit
+
+	_, err := adapter.Transcribe(context.Background(), audioData)
+	if err == nil {
+		t.Error("expected error for missing model file")
+	}
+	if err != nil && !contains(err.Error(), "model file not found") {
+		t.Errorf("expected 'model file not found' error, got: %v", err)
+	}
+}
+
+func TestWhisperCppAdapter_LanguageConversion(t *testing.T) {
+	// verify adapter stores language for later conversion
+	adapter := NewWhisperCppAdapter("/fake/model.bin", "", 4)
+	if adapter.language != "" {
+		t.Errorf("expected empty language for auto, got: %q", adapter.language)
+	}
+
+	adapter = NewWhisperCppAdapter("/fake/model.bin", "en", 4)
+	if adapter.language != "en" {
+		t.Errorf("expected 'en' language, got: %q", adapter.language)
+	}
+}
+
+func TestWhisperCppAdapter_ThreadsConfig(t *testing.T) {
+	adapter := NewWhisperCppAdapter("/fake/model.bin", "en", 0)
+	if adapter.threads != 0 {
+		t.Errorf("expected threads=0 (auto), got: %d", adapter.threads)
+	}
+
+	adapter = NewWhisperCppAdapter("/fake/model.bin", "en", 8)
+	if adapter.threads != 8 {
+		t.Errorf("expected threads=8, got: %d", adapter.threads)
+	}
+}
+
+func TestWhisperCppAdapter_TempFileCleanup(t *testing.T) {
+	// this test requires whisper-cli and a model to be installed
+	// skip if not available
+	modelPath := os.Getenv("WHISPER_TEST_MODEL")
+	if modelPath == "" {
+		t.Skip("WHISPER_TEST_MODEL not set, skipping temp file cleanup test")
+	}
+
+	adapter := NewWhisperCppAdapter(modelPath, "en", 4)
+
+	// create minimal audio data
+	audioData := make([]byte, 32000)
+
+	// run transcription
+	_, _ = adapter.Transcribe(context.Background(), audioData)
+
+	// check that temp file was cleaned up
+	// (we can't easily verify this without modifying the adapter to expose temp path)
+	// this is more of a visual/log verification
+}
+
+func TestWhisperCppAdapter_ContextCancellation(t *testing.T) {
+	// skip if whisper-cli not installed
+	if _, err := os.Stat("/usr/local/bin/whisper-cli"); os.IsNotExist(err) {
+		t.Skip("whisper-cli not installed")
+	}
+
+	// create a fake model file for this test
+	tmpDir := t.TempDir()
+	fakeModel := filepath.Join(tmpDir, "fake.bin")
+	if err := os.WriteFile(fakeModel, []byte("fake"), 0600); err != nil {
+		t.Fatalf("failed to create fake model: %v", err)
+	}
+
+	adapter := NewWhisperCppAdapter(fakeModel, "en", 4)
+
+	ctx, cancel := context.WithCancel(context.Background())
+	cancel() // cancel immediately
+
+	// create minimal audio data
+	audioData := make([]byte, 32000)
+
+	_, err := adapter.Transcribe(ctx, audioData)
+	if err == nil {
+		t.Error("expected error for cancelled context")
+	}
+}
+
+func contains(s, substr string) bool {
+	return len(s) >= len(substr) && (s == substr || len(s) > 0 && containsHelper(s, substr))
+}
+
+func containsHelper(s, substr string) bool {
+	for i := 0; i <= len(s)-len(substr); i++ {
+		if s[i:i+len(substr)] == substr {
+			return true
+		}
+	}
+	return false
+}