Test class getting DUPLICATE_USERNAME error even with unique username workaround

Question

I have a class that creates a user from a contact record, so I uses the Salesforce knowledge article to make sure the email address of the test contact is unique, so it can generate a unique username, but I'm still getting the duplicate username error.

What could be causing this?

Here is my test class:

@isTest
public with sharing class CreateCommunityUser_Test {
@isTest
public static void testUserCreation(){
    ID StandardAccountRecordID = [SELECT ID FROM RecordType WHERE SobjectType = 'Account' AND Name = 'Standard Account' LIMIT 1].Id;

    String orgId = UserInfo.getOrganizationId();
    String dateString = String.valueof(Datetime.now()).replace(' ','').replace(':','').replace('-','');
    Integer randomInt = Integer.valueOf(math.rint(math.random()*1000000));
    String uniqueName = orgId + dateString + randomInt;

    List<Account> accountsToInsert = new List<Account>();
    Account testAccount = new Account(
        recordTypeId = StandardAccountRecordID
    );
    testAccount = (Account)TestFactory.createSObject(testAccount);
    accountsToInsert.add(testAccount);
    insert accountsToInsert;

    Contact c = new Contact(
        FirstName = 'User',
        LastName = 'Test',
        AccountId = testAccount.Id,
        TDW_Access_Type__c = 'Product',
        Email = uniqueName + '@test' + orgId + '.org'
    );

    insert c;
    List<Id> contacts = new List<Id>();
    contacts.add(c.Id);

    // Set mock callout class 
    Test.setMock(HttpCalloutMock.class, new MockHttpResponseGenerator());
    
    // Call method to test.
    // This causes a fake response to be sent
    // from the class that implements HttpCalloutMock. 
    test.startTest();
    CreateCommunityUser.createExternalUser(contacts);
    test.stopTest();
            
  
}
}

Here's the class:

public without sharing class CreateCommunityUser {
@InvocableMethod(label='Create Community User' description='Creates TDW Access Community User' category='Contact')
public static void createExternalUser(List<Id> contactIds){
    Id contactId = contactIds[0];
    Id userProfileId = [SELECT Id FROM Profile WHERE Name = 'TDW Access User' LIMIT 1].Id;
    Contact userContact = [SELECT Email,FirstName,LastName, TDW_Access_Type__c,AccountId  FROM Contact WHERE Id = :contactId LIMIT 1];
    User u = new User();
    u.Username = userContact.Email;
    u.Email = userContact.Email;
    u.FirstName = userContact.FirstName;
    u.LastName = userContact.LastName;
    u.Community_Experience__c = userContact.TDW_Access_Type__c;
    u.UserPreferencesHideS1BrowserUI = true;
    u.ProfileId = userProfileId;
    u.ContactId = userContact.Id;
    u.UserPreferencesHideSfxWelcomeMat = true;
    u.LocaleSidKey = 'en_US';
    u.LanguageLocaleKey = 'en_US';
    u.UserPermissionsSFContentUser = true;
    u.Alias = userContact.FirstName.left(4) + '.' + userContact.LastName.left(3);
    u.TimeZoneSidKey = 'America/Chicago';
    u.EmailEncodingKey = 'ISO-8859-1';
    

    // generating unique value for community nickname. 
    String nickname = ((userContact.FirstName != null && userContact.FirstName.length() > 0) ? userContact.FirstName.substring(0,1) : '' ) + userContact.LastName.substring(0,1);
            nickname += String.valueOf(Crypto.getRandomInteger()).substring(1,7);
    u.CommunityNickname = nickname;


    System.debug('Creating user');

    insert u;

    System.debug('New user created with Id: ' + u.Id);

    JSONUserGenerator.generateJSONContent(u.Id);



}
}

Answer 1

The issue was that the CreateCommunityUser class was being invoked by a flow when the new contact was created, and then invoked again when I called CreateCommunityUser.createExternalUser(contacts);