### Question:
AttributesUtil { public static Map<String, Map<String, String>> loadAttributes( Node attributesNode ) { Map<String, Map<String, String>> attributesMap = new HashMap<>(); if ( attributesNode != null ) { List<Node> groupNodes = XmlHandler.getNodes( attributesNode, XML_TAG_GROUP ); for ( Node groupNode : groupNodes ) { String groupName = XmlHandler.getTagValue( groupNode, "name" ); Map<String, String> attributes = new HashMap<>(); attributesMap.put( groupName, attributes ); List<Node> attributeNodes = XmlHandler.getNodes( groupNode, XML_TAG_ATTRIBUTE ); for ( Node attributeNode : attributeNodes ) { String key = XmlHandler.getTagValue( attributeNode, "key" ); String value = XmlHandler.getTagValue( attributeNode, "value" ); if ( key != null && value != null ) { attributes.put( key, value ); } } } } return attributesMap; }  static String getAttributesXml( Map<String, Map<String, String>> attributesMap ); static String getAttributesXml( Map<String, Map<String, String>> attributesMap, String xmlTag ); static Map<String, Map<String, String>> loadAttributes( Node attributesNode ); static final String XML_TAG; static final String XML_TAG_GROUP; static final String XML_TAG_ATTRIBUTE; }### Answer:
@Test public void testLoadAttributes_NullParameter() { PowerMockito.when( AttributesUtil.loadAttributes( any( Node.class ) ) ).thenCallRealMethod(); Map<String, Map<String, String>> attributesMap = AttributesUtil.loadAttributes( null ); assertNotNull( attributesMap ); assertTrue( attributesMap.isEmpty() ); }