shadows/framework/src/main/java/org/robolectric/shadows/ShadowAudioManager.java
@Implementation
  protected void adjustStreamVolume(int streamType, int direction, int flags) {
    switch (direction) {
      case AudioManager.ADJUST_MUTE:
        streamsMuteState.put(streamType, true);
        break;
      case AudioManager.ADJUST_UNMUTE:
        streamsMuteState.put(streamType, false);
        break;
      default:
        break;
    }
  }
@Implementation
  protected void adjustStreamVolume(int streamType, int direction, int flags) {
    switch (direction) {
      case AudioManager.ADJUST_MUTE:
        streamsMuteState.put(streamType, true);
        break;
      case AudioManager.ADJUST_UNMUTE:
        streamsMuteState.put(streamType, false);
        break;
      default:
        break;
    }
  }
Implements {@link AudioManager#adjustStreamVolume(int, int, int)}.

<p>Currently supports only the directions {@link AudioManager#ADJUST_MUTE} and {@link
AudioManager#ADJUST_UNMUTE}.