Helper Class test class

public with sharing class RenewalUtils {
 public static String OppLineDisc(String QOppID, String Quoteid, String ProdCode) {
   Decimal Disctot;
   Opportunity ropp = [select Prior_Year_Opportunity__c from opportunity where id = :QOppID and recordtype.name = 'Renewal Opportunity']; 
   List<AggregateResult>  Opplst = [select avg(Discount_Percent__c) totdisc
                                    from OpportunityLineItem 
                                    where Opportunityid = :ropp.Prior_Year_Opportunity__c and 
                                          product2.productcode = :ProdCode 
                                          ];
   for (AggregateResult arOpplst : Opplst)
     {
       Disctot = ((Decimal)arOpplst.get('totdisc'));
     }                                              
     system.debug(Disctot);
      return string.valueof(Disctot);
 }
public static String OppLineID(String QOppID, String Quoteid, String ProdCode) {
   Opportunity ropp = [select Prior_Year_Opportunity__c from opportunity where id = :QOppID and recordtype.name = 'Renewal Opportunity']; 
   OpportunityLineItem  Opplst = [select id
                                    from OpportunityLineItem 
                                    where Opportunityid = :ropp.Prior_Year_Opportunity__c and 
                                          product2.productcode = :ProdCode limit 1
                                          ];
     system.debug(Opplst.id);
      return string.valueof(Opplst.id);
 } 
}