### Question:
DictionaryHelper { public static void registerEntityType( String entityType ) { registerEntityType( null, entityType, null ); } protected  DictionaryHelper(); static void registerEntityType( String entityType ); static void registerEntityType(
    final String linkType, final String entityType, final String parentEntityType ); @VisibleForTesting static void clearEntityRegistry(); static void registerStructuralLinkType( String linkType ); static void registerDataFlowLinkType( String linkType ); static boolean isStructuralLinkType( String linkType ); static boolean isDataFlowLinkType( String linkType ); static boolean isEntityType( String nodeType ); static void registerEntityTypes(); static String getNonEntityToEntityLinkType(); static boolean addNonEntityToEntityLinkTypeLabel(); static Set<String> getEntityLinkTypes(); static String getParentEntityNodeType( final String linkType, final String nodeName ); static boolean linksToRoot( final String linkType, final String nodeName ); static String getCategoryForType( String type ); static String getColorForCategory( String category ); static IMetaverseNode createMetaverseNode( String id, String name, String type, Properties properties ); static IMetaverseNode addChildNode( String id, String name, String type,
                                             Properties properties, IMetaverseNode parent, String relationship ); static final Set<String> STRUCTURAL_LINK_TYPES; static final Set<String> ENTITY_NODE_TYPES; static final Set<String> DATAFLOW_LINK_TYPES; static Map<String, String> typeCategoryMap; }### Answer:
@Test public void testRegisterEntityType() { int numEntityNodes = DictionaryHelper.ENTITY_NODE_TYPES.size(); assertEquals( numEntityNodes, DictionaryHelper.ENTITY_NODE_TYPES.size() ); DictionaryHelper.registerEntityType( null ); assertEquals( numEntityNodes, DictionaryHelper.ENTITY_NODE_TYPES.size() ); DictionaryHelper.registerEntityType( "" ); assertEquals( numEntityNodes, DictionaryHelper.ENTITY_NODE_TYPES.size() ); DictionaryHelper.registerEntityType( " " ); assertEquals( numEntityNodes, DictionaryHelper.ENTITY_NODE_TYPES.size() ); DictionaryHelper.registerEntityType( "newEntityType" ); assertTrue( DictionaryHelper.ENTITY_NODE_TYPES.contains( "newEntityType" ) ); assertEquals( numEntityNodes + 1, DictionaryHelper.ENTITY_NODE_TYPES.size() ); }