Apex test class throwing error for lead conversion

Question

I am writing a test class but on running I am getting the following error continuously.

System.DmlException: ConvertLead failed. First exception on row 0; first error: CANNOT_UPDATE_CONVERTED_LEAD, This lead was already converted to the contact Lead1234 on 25/07/2019.: []

Can anyone helps me out on this issue?

My apex class is below.

@isTest
public class TestContactCreationFromLead {
  static testMethod void ContactCreationFromLeadtrigger(){
Account acc = new Account(Name='TestAccount',Pardot_Program_Name__c='Accounting and Finance');
insert acc;
Account acc1 = new Account(Name='TestAccount',Pardot_Program_Name__c='Disability Studies');
insert acc1;
Lead le1 = new Lead(LastName='Lead1234', Email='Lead1@gtg4.com', Status='New',Company='Test',Expected_Year_of_Enrolment__c=2028,What_is_your_primary_program_of_interest__c='Accounting and Finance',Other_Programs_of_Interest__c='Disability Studies',Parent_or_guardian__c=false);
insert le1;
test.startTest();
if(le1.Parent_or_guardian__c=false){
Contact c = new Contact(AccountId=acc.Id,LastName=le1.LastName,Email=le1.Email);
insert C;
   hed__Affiliation__c hed = new hed__Affiliation__c(hed__Account__c=acc.Id,hed__Contact__c=c.Id,hed__Primary__c=true);
    insert hed;
   hed__Affiliation__c hed1 = new hed__Affiliation__c(hed__Account__c=acc1.Id,hed__Contact__c=c.Id,hed__Primary__c=false);
    insert hed1;
}
Lead l1 = new Lead(LastName='Lead245', Email='Lead1@g234.com', Status='New',Company='Test',Expected_Year_of_Enrolment__c=2028,What_is_your_primary_program_of_interest__c='Accounting and Finance',Other_Programs_of_Interest__c='Disability Studies',Parent_First_Name__c='ParentF',Parent_Last_Name__c='ParentL',Parent_Email__c='Parentemail@g.in',Parent_or_guardian__c=true);
insert l1;
if(l1.Parent_or_guardian__c=true){
    Contact c1= new Contact(AccountId=acc.Id,LastName=l1.LastName,Email=l1.Email);
    insert c1;
    Contact c2= new Contact(AccountId=acc.Id,LastName=l1.Parent_Last_Name__c,FirstName=l1.Parent_First_Name__c,Email=l1.Parent_Email__c);
    Insert c2;
    hed__Affiliation__c hed2 = new hed__Affiliation__c(hed__Account__c=acc.Id,hed__Contact__c=c1.Id,hed__Primary__c=true);
    insert hed2;
    hed__Affiliation__c hed3 = new hed__Affiliation__c(hed__Account__c=acc1.Id,hed__Contact__c=c1.Id,hed__Primary__c=false);
    insert hed3;
    hed__Relationship__c rel = new hed__Relationship__c(hed__Contact__c=c1.Id,hed__RelatedContact__c=c2.Id,hed__Type__c='Parent');
    insert rel;
}
database.leadConvert lc = new database.leadConvert();
       lc.setLeadId(le1.id);

       leadStatus convertStatus = [SELECT Id, MasterLabel FROM LeadStatus WHERE IsConverted=true LIMIT 1];
        lc.setConvertedStatus(convertStatus.MasterLabel);
  String currentemail = le1.Email;
  List<Contact> id1 = [SELECT Id, Email,AccountId FROM Contact WHERE Email = :currentemail];
            String Idcon;
            string accname123;
             for(Contact ce1 : id1){
                      Idcon = ce1.Id;
                      accname123 = ce1.AccountId;
          }
     lc.setContactId(Idcon);
              lc.setAccountId(accname123);

       Database.LeadConvertResult lcr = Database.convertLead(lc);
       System.assert(lcr.isSuccess());
test.stopTest();
   }
    }

Answer 1

Achieved it finally, I should not convert lead in test class as it is already converted by trigger, so instead converting lead in test class need to fetch the converted Id.

replaced the conversion lead with following code and finally achieved.

    le1 = [SELECT ConvertedAccountId FROM Lead WHERE Id = :le1.Id];
    System.assertNotEquals(null, le1.ConvertedAccountId, 'Expected lead to be converted.');
    }