Testing Wrapper Class: Constructor not defined: [ClassName].<Constructor>()

Question

I am trying to test this (uploaded to pastebin due length) wrapper class. I was trying to follow two previous SFSE's, however I am getting errors. See code below (errors in comments):

@isTest
public class testAddBasketGasQuoteFromMonitor{
    static testMethod void validateTestMyClass() {
        electricity_meter__c testGasMeter = testUtil.initGasMeter();
    String meterNameInner = String.valueOf( testGasMeter.get('Name') );
    String meterAQ = String.valueOf('100');
    String meterID = String.valueOf('123123123123');  
        AddBasketGasQuoteFromMonitor.WrapperClassEx testWrapperPack = new AddBasketGasQuoteFromMonitor.WrapperClassEx(testGasMeter,meterNameInner,meterAQ,meterID);
        // Error: Constructor not defined: [AddBasketGasQuoteFromMonitor].<Constructor>()
        //AddBasketGasQuoteFromMonitor controller = new AddBasketGasQuoteFromMonitor();
        // Error: Variable does not exist: getwrapperObj
        //for (AddBasketGasQuoteFromMonitor.WrapperClassEx wrap : testWrapperPack.getwrapperObj){}       
}

Any ideas on what I am doing wrong?

EDIT: Wrapper class code below

public with sharing class AddBasketGasQuoteFromMonitor{
    @TestVisible Public List<WrapperClassEx> WrapperList{get;set;}
    public AddBasketGasQuoteFromMonitor(ApexPages.StandardSetController controller) {
      mycon = controller;
      Selectedmeters = mycon.getSelected();
    }
    public AddBasketGasQuoteFromMonitor(ApexPages.StandardController controller) {
      mycon2 = controller;

    }
    public List<sobject> Selectedmeters {get; set;} 
    ApexPages.StandardSetController mycon;
    ApexPages.StandardController mycon2; 
   @TestVisible Public List<WrapperClassEx> getwrapperObj(){
      id lineId = mycon2.getId();  
      //List<Account> accList = [Select id,name from account limit 5];
      //List<Line_del__c> SelectedLines = [select Linked_Monitor_Line__r.id from Line_del__c where id in: SelectedMeters];
      List<electricity_meter__c> MeterList = [Select id,name,AQ__c,meter_details__c from electricity_meter__c where (Linked_Monitor_Line__c =: lineId)]; 
      WrapperList = New List<WrapperClassEx>();
      for(electricity_meter__c met: MeterList){
        String meterNameInner = String.valueOf( met.get('Name') );
        String meterAQ = String.valueOf( met.get('AQ__c') );
        String meterID = String.valueOf( met.get('meter_details__c') );  
        WrapperList.add(New WrapperClassEx(met,meterNameInner,meterAQ,meterID )); 
      } 
      return WrapperList;
   } 
Public String options{get;set;}
    // Get the list of suppliers
    public List<SelectOption> getSuppliers(){
        List<SelectOption> options = new List<SelectOption>();        
        Schema.DescribeFieldResult fieldResult =
        Electricity_Meter__c.Current_Supplier__c.getDescribe();
        List<Schema.PicklistEntry> ple = fieldResult.getPicklistValues();        
        for( Schema.PicklistEntry f : ple)
            {
            options.add(new SelectOption(f.getLabel(), f.getValue()));
            }       
        return options;
    }

   @TestVisible Public Class WrapperClassEx{
     Public     Account     accObj  {get;set;}
     Public     Sobject     elecObj {get;set;}
     Public     Boolean     checkBox{get;set;}
     Public     string      meterName{get;set;}
     Public     double      dayrate {get;set;}
     Public     string      meterID {get;set;}  
     Public     double      standing{get;set;}
     Public     string      supplier{get;set;} 
     Public     string      AQ      {get;set;}
     Public     string      AQQ     {get;set;}          
     Public WrapperClassEx(sobject accRec, string meterNameMethodVar, string meterAQ, string meterIDs ){
        elecObj = accRec;
        meterName = meterNameMethodVar;
         AQ=meterAQ;
         meterID=meterIDs;
     }
   }

    public List<Quote__C> newQuotes {get; set;}  

    public void save(){  
        newQuotes = new list<Quote__c>();
        for (WrapperClassEx wrap : WrapperList){
            newQuotes.add(new Quote__c(
                consumption__c=decimal.valueOf(wrap.AQQ),
                Day_rate__c=decimal.valueOf(wrap.dayrate),
                Standing_Charge__c=decimal.valueOf(wrap.standing), 
                Supplier__c=wrap.supplier,
                All_Products__c=wrap.elecObj.id
                ));
            }

        try {
            insert newQuotes;
        } catch (DmlException ex){
            ApexPages.addMessages(ex);
        } 
    }
}

Answer 1

The problem is that you try to create an instance of AddBasketGasQuoteFromMonitor with the line AddBasketGasQuoteFromMonitor controller = new AddBasketGasQuoteFromMonitor(); However, your class AddBasketGasQuoteFromMonitor only has a constructor that takes a ApexPages.StandardController as a parameter. So in your test, when you want to create an instance, you have to supply a StandardController.

For example:

PageReference pr = Page.MyPage;
Test.SetCurrentPage(pr);
electricity_meter__c testGasMeter = testUtil.initGasMeter();
ApexPages.StandardController stdC = new ApexPages.StandardController((sObject)testGasMeter);

AddBasketGasQuoteFromMonitor controller = new AddBasketGasQuoteFromMonitor(stdC);