I'm Trying to get the code coverage for the following trigger.

Trigger AutoConverter on Lead (after insert,after update,before update) {
 if(trigger.isafter)
{
          LeadStatus convertStatus = [
          select MasterLabel
          from LeadStatus
          where IsConverted = true
          limit 1
          ];
         List<Database.LeadConvert> leadConverts = new List<Database.LeadConvert>();

          for (Lead lead: Trigger.new) {
          if (!lead.isConverted && lead.Is_the_lead_from_CSA_Sign_Up_page__c == 'Yes') {
               Database.LeadConvert lc = new Database.LeadConvert();
               String oppName = lead.Name;
               
               lc.setLeadId(lead.Id);
               //lc.setOpportunityName(oppName);
               lc.setDoNotCreateOpportunity(true);
               lc.setConvertedStatus(convertStatus.MasterLabel);
               
               leadConverts.add(lc);
          }
        }
       if (!leadConverts.isEmpty()) {
          List<Database.LeadConvertResult> lcr = Database.convertLead(leadConverts);
          if(trigger.isupdate&&lcr[0].success==true){
                  ///
       }
       }
}

Here's the test class:

@isTest
private class Testleadconversiontrigger
{
    private static id leadid;
    //{
      static{
          
          Lead L1 = new Lead();
          L1.firstname = 'f1';
          L1.lastname = 'l1';
          L1.title = 'manager';
          L1.leadsource = 'word of mouth';
          L1.company = 'MOD';
          L1.Is_the_lead_from_CSA_Sign_Up_page__c='Yes';
          Insert L1;
          
          leadid=L1.id;
      }
      static testMethod void Test_LeadConvert(){
          Database.LeadConvert lc = new database.LeadConvert();
          lc.setLeadId(leadid);
          lc.setDoNotCreateOpportunity(true);
          test.StartTest();
          LeadStatus convertStatus = [Select Id, MasterLabel from LeadStatus 
          where IsConverted=true limit 1];         
          //lc.setOwnerId(testUser1.id);
          lc.setConvertedStatus(convertStatus.MasterLabel);
          Database.LeadConvertResult lcr = Database.convertLead(lc);
          System.assert(lcr.isSuccess());
          test.StopTest();
     }
    //}
}

But i'm getting the follwoing error on line no 28 in test class,

Error MessageSystem.DmlException: ConvertLead failed. First exception on row 0; first error: ENTITY_IS_DELETED, entity is deleted: []
Stack TraceClass.Testleadconversiontrigger.Test_LeadConvert: line 28, column 1

Can anyone help me on this?

Thanks in Advance.