anchor.diff:              'country': null
             }
           ],
  -        'avatar': null
  +        'avatar': null,
  +        'birthday': null
         },
       ),
     ]);
  
positive.code:       "emails": [],
        "phones": [],
        "postalAddresses": [],
        "avatar": null
      });
    });
  }
  
negative.code:   });
  
    test('should get contacts', () async {
      final contacts = await ContactsService.getContacts();
      expect(contacts.length, 2);
      expect(contacts, everyElement(isInstanceOf<Contact>()));
      expect(contacts.toList()[0].givenName, 'givenName1');
      expect(contacts.toList()[1].postalAddresses.toList()[0].label, 'label');
      expect(contacts.toList()[1].emails.toList()[0].label, 'label');
      expect(contacts.toList()[1].birthday, DateTime(1994, 2, 1));
    });
  
    test('should add contact', () async {
  