### Question:
GroupByDefaultTreeBuilder implements ActiveGroupByTreeBuilder, AvailableGroupByTreeBuilder { @Override public String getGroupByName() { return "Source"; }  Set<String> getCategories(); DataGroupController getDataGroupController(); @Override String getGroupByName(); @Override GroupCategorizer getGroupCategorizer(); @Override Comparator<? super DataGroupInfo> getGroupComparator(); @Override Predicate<DataGroupInfo> getDataCategoryFilter(); @Override Predicate<DataGroupInfo> getGroupFilter(); Toolbox getToolbox(); @Override TreeOptions getTreeOptions(); @Override Comparator<? super DataTypeInfo> getTypeComparator(); @Override void initializeForActive(Toolbox toolbox); @Override void initializeForAvailable(Toolbox toolbox); @Override void setGroupComparator(Comparator<? super DataGroupInfo> comp); void setTypeComparator(Comparator<? super DataTypeInfo> comp); boolean isActiveGroupsOnly(); boolean isSubNodesForMultiMemberGroups();  }### Answer:
@Test public void testGetGroupByName() { GroupByDefaultTreeBuilder builder = new GroupByDefaultTreeBuilder(); assertEquals("Source", builder.getGroupByName()); }