shadows/framework/src/main/java/org/robolectric/shadows/ShadowSoundPool.java
@Implementation
  protected int load(String path, int priority) {
    int soundId = soundIds.getAndIncrement();
    idToPaths.put(soundId, path);
    return soundId;
  }
@Implementation
  protected int load(String path, int priority) {
    int soundId = soundIds.getAndIncrement();
    idToPaths.put(soundId, path);
    return soundId;
  }
FileDescriptor which would make it difficult to check if a given sound has been placed.