### Question:
LabelValueExtractorRegistry { public static LabelValueExtractorRegistry getInstance() { return INSTANCE; } private  LabelValueExtractorRegistry(); static LabelValueExtractorRegistry getInstance(); synchronized void registerExtractors(ClassLoader classLoader); @SuppressWarnings("unchecked") Optional<Set<LabelValueExtractor<T>>> getLabelValueExtractors(Class<T> sourceType); void applyLabelValueExtractors(Class<T> sourceType, T source, BiConsumer<String, Set<Object>> extractedValuesConsumer);  }### Answer:
@Test public void getInstance() { assertThat(LabelValueExtractorRegistry.getInstance()).isNotNull(); }
@Test public void defaultExtractorsAreLoaded() { LabelValueExtractorRegistry registry = LabelValueExtractorRegistry.getInstance(); assertLabelExtractorsLoaded(TaskData.class, registry, DefaultLabels.AFFINITIES.name(), DefaultTaskDataAffinitiesValueExtractor.class); assertLabelExtractorsLoaded(TaskData.class, registry, DefaultLabels.SKILLS.name(), DefaultTaskDataSkillsValueExtractor.class); assertLabelExtractorsLoaded(TaskData.class, registry, TestTaskDataLabelValueExtractor.TEST_LABEL, TestTaskDataLabelValueExtractorOverride.class); assertLabelExtractorsLoaded(User.class, registry, DefaultLabels.AFFINITIES.name(), DefaultUserAffinitiesValueExtractor.class); assertLabelExtractorsLoaded(User.class, registry, DefaultLabels.SKILLS.name(), DefaultUserSkillsValueExtractor.class); }