1 files changed, 52 insertions, 0 deletions
diff --git a/src/audio/backend/silent_backend.h b/src/audio/backend/silent_backend.h
new file mode 100644
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+++ b/src/audio/backend/silent_backend.h
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+// This file is part of the 64k demo project.
+// It implements a silent test backend for testing audio.cc without hardware.
+// Useful for achieving high test coverage and triggering edge cases.
+
+#pragma once
+
+#if !defined(STRIP_ALL)
+
+#include "../audio_backend.h"
+#include <atomic>
+
+// Silent backend for testing - no audio output, pure inspection
+// Allows testing audio.cc logic (buffer management, playback time tracking)
+// without requiring audio hardware or miniaudio
+class SilentBackend : public AudioBackend {
+ public:
+  SilentBackend();
+  ~SilentBackend() override;
+
+  // AudioBackend interface
+  void init() override;
+  void start() override;
+  void shutdown() override;
+  float get_realtime_peak() override;
+
+  // Test inspection interface
+  bool is_initialized() const { return initialized_; }
+  bool is_started() const { return started_; }
+  int get_frames_rendered() const { return frames_rendered_.load(); }
+  int get_voice_trigger_count() const { return voice_trigger_count_.load(); }
+
+  // Manual control for testing edge cases
+  void set_peak(float peak) { test_peak_ = peak; }
+  void reset_stats() {
+    frames_rendered_ = 0;
+    voice_trigger_count_ = 0;
+  }
+
+  // Event hooks (inherited from AudioBackend)
+  void on_voice_triggered(float timestamp, int spectrogram_id, float volume,
+                          float pan) override;
+  void on_frames_rendered(int num_frames) override;
+
+ private:
+  bool initialized_;
+  bool started_;
+  std::atomic<int> frames_rendered_;
+  std::atomic<int> voice_trigger_count_;
+  float test_peak_; // Controllable peak for testing
+};
+
+#endif /* !defined(STRIP_ALL) */