I'm getting an error INACTIVE_OWNER_OR_USER, operation performed with inactive user, and I have been doing a lot of research and the cause that I have found for this is its attempting to assign a my lead to inactive user.  So I understand that part I think the issue is now I don't actually know how to fix it, I didn't write this trigger/test class and I'm not sure how to go forward.

Do I need to create a new Test User?  I've never worked on the Lead object before..

Edit**
I added IsActive = True the trigger user query, no luck.

Edit**
I just went talking to anyone that might have an idea about UserTypes, and they have no idea what UserType = 'PowerPartner' is.  So I changed it to a different UserType.. didn't work

Test Class

    @isTest
    private class PartnerLeadShare_test {
    static testMethod void myUnitTest1() {
    List<Lead> leadList = new List<Lead>();
    List<LeadShare> leadShareList = new list<LeadShare>(); 
    
    Lead ld = new Lead();
    ld.lastName = 'Test Zensar';
    ld.Company = 'Zensar';
    ld.Status = 'Open';
    ld.Program_EAU__c ='11';
    insert ld;
    system.debug('ld****' +ld);
    
    GroupMember groupMemberStore = [select GroupId,UserOrGroupId from GroupMember limit 1];
    
    LeadShare ls = new LeadShare(); 
    ls.LeadId = ld.id;
    ls.UserOrGroupId = groupMemberStore.UserOrGroupId ;
    ls.LeadAccessLevel = 'Edit';
    leadShareList.add(ls);
     
     if(leadShareList.size()>0){
     	system.debug('INSIDE LEADSHARE LIST.');
         insert leadShareList;
     }
     }
    }

Don't know this will help but here is my trigger..

    trigger PartnerLeadShare on Lead (after insert,after update) {

    Map<id,User>PartnerUsermap = new Map<id,user>([select id,UserType from user where      UserType = 'PowerPartner' and IsActive = True] );   
    List<GroupMember>GroupMemberList = new List<GroupMember>([select GroupId,UserOrGroupId   from GroupMember]); 
 
    System.debug('PartnerUsermap ===  '  +PartnerUsermap);
    System.debug('GroupMemberList    '+GroupMemberList );

    List<LeadShare> leadShareList = new list<LeadShare>(); 

     if(!PartnerUsermap.isEmpty()){
    for(Lead ld: trigger.new){ 
        for(GroupMember grpmem : GroupMemberList){
            if(grpmem.UserOrGroupId == ld.CreatedById){  
                LeadShare ldShare = new LeadShare (LeadId = ld.id,UserOrGroupId = grpmem.GroupId,LeadAccessLevel = 'Edit'); 
                leadShareList.add(ldShare );
            }
        }
    }
    }
    if(!leadShareList.isEmpty()){
    Database.SaveResult[] lsr = Database.insert(leadShareList,false);           
    Integer i=0;
    for(Database.SaveResult sr : lsr){
        if(!sr.isSuccess()){
        Database.Error err = sr.getErrors()[0]; 
                if(!(err.getStatusCode() == StatusCode.FIELD_FILTER_VALIDATION_EXCEPTION  
                                               &&  err.getMessage().contains('AccessLevel'))){
                   
                    trigger.newMap.get(leadShareList[i].LeadId).
                      addError(
                       'Unable to grant sharing access due to following exception: '
                       + err.getMessage());
                }
        }
       i++;
    }
    }