Stack Trace MassTransfferOwnershipController.doSearch: line 306, column 1
                   MassCaseTransferTestClass.MassCaseTransferTestClass: line 52, column 1

My Controllers method

 public PageReference doSearch()
    { 
       
        theResultList = new List<wrapperClass>();
        
        //system.debug('IN THE LOOP'+toUserFunc);
        
        if(selectedCaseFiler <> 'Select from list...' && selectedCaseFiler1 == 'Select from list...'&&  selectedCaseFiler2 == 'Select from list...')
        {
            CaseFiler = String.escapeSingleQuotes(selectedCaseFiler);
            CaseFilter = String.escapeSingleQuotes(selectedFilterValue);
            theQ = 'SELECT id,OwnerId,CaseNumber,Origin,Priority,Status,Account.Name,New_Owner__c  FROM Case WHERE OwnerId = :myId AND '+CaseFiler+' = :CaseFilter';
            
        }
        else if(selectedCaseFiler <> 'Select from list...' && selectedCaseFiler1 <> 'Select from list...' &&  selectedCaseFiler2 == 'Select from list...')
        {
              CaseFilerFirst = String.escapeSingleQuotes(selectedCaseFiler);
              CaseFilterFirst = String.escapeSingleQuotes(selectedFilterValue);
              CaseFilerFirst1 = String.escapeSingleQuotes(selectedCaseFiler1);
              CaseFilterFirst1 = String.escapeSingleQuotes(selectedFilterValue1);
             theQ = 'SELECT id,OwnerId,CaseNumber,Origin,Priority,Status,Account.Name,New_Owner__c FROM Case WHERE OwnerId = :myId AND '+CaseFilerFirst+' = :CaseFilterFirst AND '+CaseFilerFirst1+' = :CaseFilterFirst1 ';
            system.debug('IF LOOP 2 '+theQ);
        }
        else if(selectedCaseFiler <> 'Select from list...' && selectedCaseFiler1 <> 'Select from list...' &&  selectedCaseFiler2 <> 'Select from list...')
        {
            CaseFilerSecond = String.escapeSingleQuotes(selectedCaseFiler );
            CaseFilterSecond = String.escapeSingleQuotes(selectedFilterValue);
            CaseFilerSecond1 = String.escapeSingleQuotes(selectedCaseFiler1 );
            CaseFilterSecond1 = String.escapeSingleQuotes(selectedFilterValue1);
            CaseFilerSecond2 = String.escapeSingleQuotes(selectedCaseFiler2 );
            CaseFilterSecond2 = String.escapeSingleQuotes(selectedFilterValue2);
              
            theQ = 'SELECT id,OwnerId,CaseNumber,Origin,Priority,Status,Account.Name,New_Owner__c FROM Case WHERE OwnerId = :myId AND '+ CaseFilerSecond +' = :CaseFilterSecond AND '+ CaseFilerSecond1+' = :CaseFilterSecond1 AND '+CaseFilerSecond2+' = :CaseFilterSecond2 ';           
           system.debug('IF LOOP 3 '+theQ);
        }
        else
        {
        
            theQ = 'SELECT id,OwnerId,CaseNumber,Origin,Priority,Status,Account.Name,New_Owner__c FROM Case WHERE OwnerId = '+myId;
        }
        /*
        else
        {
            theQ = 'SELECT id,OwnerId FROM '+selectedObject+' WHERE OwnerId = :myId AND Stage = \''+selectedOpportunityFiler+'\'';
        }
        */
        
        system.debug('THE QUERY IS:-'+theQ);
        for(Case s : Database.Query(theQ))
        {
            system.debug('THE S:-'+s);
            wrapperClass wc = new wrapperClass(s);
            system.debug('THE WC:-'+wc);
            theResultList.add(wc);
        }
        system.debug('THE LIST IS:-'+theResultList);
        if(theResultList.isEmpty())
        {
             ApexPages.AddMessage(new ApexPages.Message(ApexPages.Severity.INFO, 'NO RECORDS FOUND.'));
             showResult = FALSE;
        }
        showResult = TRUE;
        
        
        return null;
    }

My Test Class

@isTest(SeeAllData=true)
private class MassCaseTransferTestClass
{
    static testMethod void MassCaseTransferTestClass()
    {
        Test.setCurrentPage(Page.MassTransfferOwnershipPage);

       List <User> user= [select id from User where Profile.Name = 'System Administrator'];
        
        String userId;   
        for(User usr: user)
        {
            userId = usr.id;
         }  
        
        
        Case c = new Case(OwnerId=userId,Origin='Phone',Subject='Test Case 1');
        insert c;
        
       
        
        Transffer_Ownership__c testObj = new Transffer_Ownership__c(User__c=userId);
        insert testObj; 
        
       
        ApexPages.Standardcontroller sc = New ApexPages.StandardController(testObj);
        MassTransfferOwnershipController mct = new MassTransfferOwnershipController(sc);    
        
        ApexPages.Standardcontroller sc1 = New ApexPages.StandardController(c);
        MassTransfferOwnershipController mct1 = new MassTransfferOwnershipController(sc1);    
        
        
        
        mct1.selectedCaseFiler = 'Origin';
        mct1.selectedCaseFiler1 = 'Origin';
        mct1.selectedCaseFiler2 = 'Origin';
       
        
        mct.getObjectsList(); //Covered
        mct.getblockChoices(); //Covered
        mct.getCaseFilersList(); //Covered
        mct1.getFiltersList(); //Covered
        
        mct.userPopulate();
        mct.touserPopulate();
        
        
        mct1.getOpportunityFilersList();
       
        mct1.getFiltersList1();
        mct1.getFiltersList2();
        mct1.doSearch();
        mct1.doTransfer(); 
        mct1.doTransfer1(); 
        mct1.finalMethod(); 
        
    }
    
    static testMethod void MassCaseTransferTestClass_2()
    {
    
      List<User> user = [select id from User where Profile.Name = 'System Administrator'];
      
      String userId ;
      for(User usr: user)
        {
            userId  = usr.id;
        }
        
      Case c2 = new Case(OwnerId=userId ,Priority='High',Subject='Test Case 2');
      insert c2;
      
      Transffer_Ownership__c testObj = new Transffer_Ownership__c(User__c=userId);
      insert testObj;
        
        
       
        ApexPages.Standardcontroller sc = New ApexPages.StandardController(testObj);
        MassTransfferOwnershipController mct = new MassTransfferOwnershipController(sc);    
      
      ApexPages.Standardcontroller sc2 = New ApexPages.StandardController(c2);
      MassTransfferOwnershipController mct2 = new MassTransfferOwnershipController(sc2);   

      
 
      mct2.selectedCaseFiler = 'Priority';
      mct2.selectedCaseFiler1 = 'Priority';
      mct2.selectedCaseFiler2 = 'Priority'; 
      
      
       mct.getObjectsList(); //Covered
        mct.getblockChoices(); //Covered
        mct.getCaseFilersList(); //Covered
        mct2.getFiltersList(); //Covered
        
        mct.userPopulate();
        mct.touserPopulate();
        
        
        mct2.getOpportunityFilersList();
       
        
        mct2.getFiltersList1();
        mct2.getFiltersList2();
        mct2.doSearch();
        mct2.doTransfer();
   
       
    }
    
    static testMethod void MassCaseTransferTestClass_3()
    {
    
      List<User> user = [select id from User where Profile.Name = 'System Administrator'];
      
      String userId ;
      
       for(User usr: user)
        {
            userId = usr.id;
        }
      
          
      Case c3 = new Case(OwnerId=userId ,Status='Open',Subject='Test Case 2');
      insert c3;
      
      Transffer_Ownership__c testObj = new Transffer_Ownership__c(User__c=userId);
      insert testObj;
        
        
       
        ApexPages.Standardcontroller sc = New ApexPages.StandardController(testObj);
        MassTransfferOwnershipController mct = new MassTransfferOwnershipController(sc);    
      
      ApexPages.Standardcontroller sc3 = New ApexPages.StandardController(c3);
      MassTransfferOwnershipController mct3 = new MassTransfferOwnershipController(sc3);   

      
 
      mct3.selectedCaseFiler = 'Status';
      mct3.selectedCaseFiler1 = 'Status';
      mct3.selectedCaseFiler2 = 'Status'; 
      
      
       mct.getObjectsList(); //Covered
        mct.getblockChoices(); //Covered
        mct.getCaseFilersList(); //Covered
        mct3.getFiltersList(); //Covered
        
        mct.userPopulate();
        mct.touserPopulate();
        
        
        mct3.getOpportunityFilersList();
       
        
        mct3.getFiltersList1();
        mct3.getFiltersList2();
        mct3.doSearch();
        mct3.doTransfer();
   
    }

}