Hi everyone,
I am new bie to Salesforce.
This is my first  Test class.
I tried but somewhere i did mistake.
anyone give me guidelines to solve this.
 

My class


public class opentasks {

    public List<OpenActivity> open{get;set;}

    public Id leadld{get;set;}
   
    public list<wrapperclass> listwrapper{get;set;}
    

    public opentasks(ApexPages.StandardController controller){

        leadld = ApexPages.CurrentPage().getparameters().get('id');
        list<task> open1 =new list<Task>();

        listwrapper = new list<wrapperclass>();
         


        list<lead>   le =[SELECT Name, (Select Id,Subject, WhoId, ActivityDate,Status, Priority, OwnerId FROM Tasks WHERE IsClosed=false)

                            FROM Lead WHERE Id = :leadld];

        if(!le.isEmpty()){
            
            for(Task k: le[0].Tasks)

            {

               listwrapper.add(new Wrapperclass(k));
               
            }

        }

    }

     

    public class wrapperclass

    {
        public  boolean checked{get;set;}

        public Task k{get;set;}

        public Wrapperclass(Task k){

            this.k=k;

        }

    }

  public PageReference close()

    {  

        list<Task> listofopen=new list<Task>();

        if(!listwrapper.isEmpty()){

            for(Integer i=0; i<listwrapper.size();i++)

            {
                wrapperclass w = listwrapper[i];
           
                if(w.checked==true){
                    system.debug(w);
                    w.k.status='completed';
                    listofopen.add(w.k);
                    listwrapper.remove(i);
                    i--;
   
                                }
             
            }

        }

        if(listofopen.isEmpty())

        {

            ApexPages.addMessage(new ApexPages.Message(ApexPages.Severity.ERROR,'Select atleast one column '));

        }

        else{

           update listofopen;   

        }
       

My test class:

public class c{
static TestMethod void testforlead()
{ 
Test.StartTest();
User user =new User(Id=UserInfo.getUserID());

System.runAs(usr){
Lead l1=new Lead();
l1.Text(80)='shobana';
l1.Company='rix';
l1.Status='Working-contacted';
Insert l1;

Task t1=new Task();
t1.Owner='shoba shoba';
t1.Subject='cc';
t1.Priority='High';
t1.Status='In progress';
t1.Whoid=l1.Id;
Insert t1;
 ApexPages.StandardController stdcontroller = new ApexPages.Standardcontroller(l1);
 opentasks cls= new opentasks( stdcontroller);
 cls.close();
 for(wrapperclass w:cls.listwrapper)

            {
              
 w.Checked=true;
break;
 } 

cls.close();
}
Test.stopTest();
 
 }
 
}

Thank you in advance.