### Question:
Audio { public void playSound(AudioInputStream stream, float volume) { init(); for (int i = headIndex; i != tailIndex; i = (i + 1) % MAX_PENDING) { if (getPendingAudio()[i].getStream() == stream) { getPendingAudio()[i].setVolume(Math.max(volume, getPendingAudio()[i].getVolume())); return; } } getPendingAudio()[tailIndex] = new PlayMessage(stream, volume); tailIndex = (tailIndex + 1) % MAX_PENDING; } Audio(); static Audio getInstance(); synchronized void stopService(); synchronized boolean isServiceRunning(); void init(); void playSound(AudioInputStream stream, float volume); AudioInputStream getAudioStream(String filePath); PlayMessage[] getPendingAudio();  }### Answer:
@Test public void testPlaySound() throws UnsupportedAudioFileException, IOException, InterruptedException { audio.playSound(audio.getAudioStream("./etc/Bass-Drum-1.wav"), -10.0f); assertTrue(audio.isServiceRunning()); Thread.sleep(5000); audio.stopService(); assertFalse(audio.isServiceRunning()); }