Add transcription provider comparison chain

internal/transcription/client_test.go

@@ -23,6 +23,41 @@ func TestAdjustLeadSilence(t *testing.T) {
 	}
 }
 
+func TestNormalizeProviderOrder(t *testing.T) {
+	got := normalizeProviderOrder([]string{"whisperx", "qwen", "voxtral", "qwen2-audio"})
+	want := []string{ProviderWhisperX, ProviderQwenAudio, ProviderVoxtral}
+	if len(got) != len(want) {
+		t.Fatalf("providers = %#v, want %#v", got, want)
+	}
+	for i := range want {
+		if got[i] != want[i] {
+			t.Fatalf("providers = %#v, want %#v", got, want)
+		}
+	}
+}
+
+func TestNewWithOptionsBuildsComparisonProviders(t *testing.T) {
+	client := NewWithOptions(Options{
+		Providers:        []string{"whisperx", "qwen2-audio", "voxtral-small"},
+		WhisperXURL:      "http://whisperx",
+		QwenAudioBaseURL: "http://qwen",
+		VoxtralBaseURL:   "http://voxtral",
+	})
+	if client == nil {
+		t.Fatal("client is nil")
+	}
+	got := make([]string, 0, len(client.providers))
+	for _, provider := range client.providers {
+		got = append(got, provider.Name)
+	}
+	want := []string{ProviderWhisperX, ProviderQwenAudio, ProviderVoxtral}
+	for i := range want {
+		if got[i] != want[i] {
+			t.Fatalf("providers = %#v, want %#v", got, want)
+		}
+	}
+}
+
 func near(got, want float64) bool {
 	return math.Abs(got-want) < 0.000001
 }