Following are the code:



@isTest
public class TestDataUtil {
  // need to set as golobal list, can be access within class
       List<Account> lstAccount = new List<Account>(); 
       List<Product2> lstProducts = new List<Product2>();
       List<Order> lstOrders = new List<Order>();


  public static List<Account> createTestRecordsAccount(Integer numRecords) {
        List<Account> accts = new List<Account>();
        for(Integer i=0;i<numRecords;i++) {
            Account acco = new Account(Name='TestAccount'+i, Phone = '123456789'+i, Fax = '123455677'+i);
            accts.add(acco);
        }
            insert accts;
          return accts;
    }

 public static List<Product2> createTestRecordsProducts(Integer numRecords) {
      List<Product2> lstProducts = new List<Product2>();
         for(Integer i=0;i<numRecords;i++) {
              Product2 prod = new Product2(Name = 'Example Product '+i,
                                        Description = 'This is the Product description.'+i,
                                        ProductCode = 'EX1234'+i,
                                        StockKeepingUnit = 'EX5678'+i,
                                        Family = 'Example Product Family'+i,
                                        QuantityUnitOfMeasure = 'inches'+i,
                                        DisplayUrl = 'https://www.DisplayUrl.com/'+i,
                                        ExternalId = 'ID #1234'+i
                                        );
                   lstProducts.add(prod);}
                    insert lstProducts;    
              return lstProducts;
     }
     
     public static List<Order> createTestOrder(Integer numRecords, Boolean ifInsert) {
          List<Order> lstOrders = new List<Order>();
         List<Account> accts =  TestDataUtil.createTestRecordsAccount(numRecords);
         List<Pricebook2> pBook =  TestDataUtil.createTestPricebook(numRecords, ifInsert);

         for(Integer i=0;i<numRecords;i++) {
          Order ordo = new Order(Name = 'Test Order ',
                                Status = 'Draft',
                                EffectiveDate = system.today(),
                                EndDate = system.today() + 4,
                                AccountId = accts[i].id,
                                Pricebook2Id =  pBook[i].Id,
                                ShippingStreet  = 'shipping Address shipping Street   );
           lstOrders.add(ordo);
                insert lstOrders;
          return lstOrders;
     }



Question:
I have added  List  'lstAccount, lstProducts, lstOrders' as golobal. 

Now adding method and returning the List where needed. 

On 'createTestOrder' method i am calling   'createTestRecordsAccount  & createTestPricebook' again. 

Is there anyway i can save the list in these golobal list 'lstAccount, lstProducts',   MEANS where-ever i need data from these method firstly i'll check the list (lstAccount..size() >0 && lstAccount !=null). 

If lstAccount.size>0, means i have the data, so no need to call 'createTestRecordsAccount ' method again. saving dml iteration. 
    
  like following: 

  public static List<Account> createTestRecordsAccount(Integer numRecords) {
        List<Account> accts = new List<Account>();
        for(Integer i=0;i<numRecords;i++) {
            Account acco = new Account(Name='TestAccount'+i, Phone = '123456789'+i, Fax = '123455677'+i);
            accts.add(acco);
        }
            insert accts;

lstAccount.add(acco);  /// saving in golobal LIST ... (how to save it)?
          return accts;
    }  



​​​​​​​Thanks in advance ......