### Question:
MatchingGoldStandard implements Serializable { public void printGSReport() { int numPositive = getPositiveExamples().size(); int numNegative = getNegativeExamples().size(); int ttl = numPositive + numNegative; double positivePerCent = (double) numPositive / (double) ttl * 100.0; double negativePerCent = (double) numNegative / (double) ttl * 100.0; logger.info(String .format("The gold standard has %d examples", ttl)); logger.info(String .format("\t%d positive examples (%.2f%%)", numPositive, positivePerCent)); logger.info(String .format("\t%d negative examples (%.2f%%)", numNegative, negativePerCent)); if (getPositiveExamples().size() != canonicalPositiveExamples.size()) { logger.warn("The gold standard contains duplicate positive examples!"); } if (getNegativeExamples().size() != canonicalNegativeExamples.size()) { logger.warn("The gold standard contains duplicate negative examples!"); } HashSet<String> allExamples = new HashSet<>(); allExamples.addAll(canonicalPositiveExamples); allExamples.addAll(canonicalNegativeExamples); if (allExamples.size() != (canonicalPositiveExamples.size() + canonicalNegativeExamples.size())) { logger.warn("The gold standard contains an example that is both labelled as positive and negative!"); } } MatchingGoldStandard(); List<Pair<String, String>> getPositiveExamples(); List<Pair<String, String>> getNegativeExamples(); void addPositiveExample(Pair<String, String> example); void addNegativeExample(Pair<String, String> example); boolean containsPositive(String id1, String id2); boolean containsPositive(Matchable record1, Matchable record2); boolean containsNegative(String id1, String id2); boolean containsNegative(Matchable record1, Matchable record2); void setComplete(boolean isComplete); boolean isComplete(); void loadFromCSVFile(File file); void writeToCSVFile(File file); void loadFromTSVFile(File file); void writeToTSVFile(File file); void printGSReport(); void printBalanceReport(); void removeNonexistingExamples(DataSet<T,?> records);  }### Answer:
@Test public void testPrintGSReport() throws IOException { MatchingGoldStandard gs = new MatchingGoldStandard(); gs.addPositiveExample(new Pair<>("a", "b")); gs.addPositiveExample(new Pair<>("a", "b")); gs.addNegativeExample(new Pair<>("a", "b")); gs.addNegativeExample(new Pair<>("a", "b")); gs.printGSReport(); }