invocable apex to find duplicate contacts using the new findDuplicates apex stuff

findDupes

public class Flow_FindDupes {
 
    //https://developer.salesforce.com/forums/?id=906F0000000AzDeIAK
    
  @InvocableMethod(label='Get Dupes' description='Returns something')
  public static List<Contact> getDuplicateContacts(List<Contact> contacts) {
 	 system.debug('contacts size = ' + contacts.size());
     list<sObject> dasContacts = new list<sobject>();
     dasContacts.addall((List<sObject>)(contacts));
      list<Contact> duplicateContacts = new list<Contact>();
      Datacloud.FindDuplicatesResult[] results = Datacloud.FindDuplicates.findDuplicates(dasContacts);
      if(results.size() > 0){
		for (Datacloud.FindDuplicatesResult findDupeResult : results) {
	  		for (Datacloud.DuplicateResult dupeResult : findDupeResult.getDuplicateResults()) {
    			for (Datacloud.MatchResult matchResult : dupeResult.getMatchResults()) {
      				for (Datacloud.MatchRecord matchRecord : matchResult.getMatchRecords()) {
        				System.debug('Duplicate Record: ' + matchRecord.getRecord());
        				contact c = (Contact) matchRecord.getRecord();
                        duplicateContacts.add(c);
      				}
    			}
  			}
		}
      }
    return duplicateContacts;
      
	}
}
    

very cool - i do recall hacking on this some years back! re the test class, if you enable duplicate rules on contact that would block the insert of those two identical contacts, i think your test class would fail. if your dupe rule is set to alert only and not to block, then you can use database.insert and set allowDuplicates to true - see this post : https://salesforce.stackexchange.com/questions/78670/disable-duplicate-check-for-apex-class

if its set to block, i'm not sure how to do a good test of it!