Hi have created test class for below class
Class
public class DispatcherNewCaseController {

   public DispatcherNewCaseController(ApexPages.StandardController controller) {
        this.controller = controller;
        system.debug('in controller');
        //getRedir();
    }
    
    public PageReference getRedir() {

        User u = [Select firstname, IsPortalEnabled__c From user Where Id = :UserInfo.getUserId()];
        system.debug('user first name=='+u.IsPortalEnabled__c);// added by santosh
        PageReference redir;

        if (u.IsPortalEnabled__c == false) {
           
            redir  = new PageReference('/500/e?retURL=/500/o');
            redir.getParameters().put('nooverride','1');
               }


         else {
             redir = new PageReference('/apex/casecreation');
           
        }

       redir.setRedirect(true);
       return redir ;
    }

   
     private final ApexPages.StandardController controller;
}

Testclass:
@istest
public class DispatcherNewCaseController{
static testMethod void DispatcherNewCaseController(){
      
     Account testAccount = new Account(name='Test Company Name',Billing_Account_Number__c='CONTROLLER');
     insert testAccount;
    
    Account testAccount2 = new Account(name='Test Company Name',Billing_Account_Number__c='CONTROLLER');   
    
     DispatcherNewCaseController dc = new DispatcherNewCaseController();
     dc.acctNum='CONTROLLER';
    
     Case ca = new Case(Subject='Test Controller Acct Case');
     ca.Product ='FinancialForce Accounting';
     ca.Product Area = 'Admin Screens';
     ca.Priority = '3-Major Problem';
    
     dc.c = ca;    
     dc.submitcase();    

insert testAccount2;
 dc.submitcase();    
}
}

Iam facing issue on test class please help me to create test class on above apex class ;;