code: protected void printGroundtruth(final String user, final Map<Long, Double> groundtruthItems, final PrintStream out, final OUTPUT_FORMAT format) {
          for (Entry<Long, Double> e : groundtruthItems.entrySet()) {
              switch (format) {
                  case TRECEVAL:
                      out.println(user + "\tQ0\t" + e.getKey() + "\t" + e.getValue());
                      break;
                  default:
                  case SIMPLE:
                      out.println(user + "\t" + e.getKey() + "\t" + e.getValue());
                      break;
              }
          }
      }
docs: Internal function to print the ground truth (the test set).
  
  @param user The user (as a String).
  @param groundtruthItems The ground truth items for the user.
  @param out Where to print.
  @param format The format of the printer.