Test Data Factory in Apex Salesforce

@isTest
public class TestDataFactory {
    public static Id createAccount(){
        Account testAcc = new Account(
            Name = 'Test Account',
            Type = 'Site'
        );
        insert testAcc;
        
        return testAcc.Id;
    }

    public static Id createContractForAccount(Id accId, String emailId){
        Contact con = new Contact();
        con.FirstName = 'First Test';
        con.LastName = 'Last Test';
        con.Email = emailId;
        con.Phone = '999-999-9999';
        con.AccountId = accId;
        con.MailingStreet = '123 Test Avenue';
        con.MailingCity = 'Test';
        con.MailingState = 'Florida';
        con.MailingPostalCode = '30010';
        con.MailingCountry = 'United States';
        insert con;
        
        return con.Id;
    }

    public static Id createContactForAccount(Id accId, String emailId){
        Contact con = new Contact();
        con.FirstName = 'First Test';
        con.LastName = 'Last Test';
        con.Email = emailId;
        con.Phone = '999-999-9999';
        con.AccountId = accId;
        con.MailingStreet = '123 Test Avenue';
        con.MailingCity = 'Test';
        con.MailingState = 'Florida';
        con.MailingPostalCode = '30010';
        con.MailingCountry = 'United States';
        insert con;
        
        return con.Id;
    }

    public static Id createOpportunityForAccount(Id accId, String Stagename){
        Opportunity opp = new Opportunity();
        opp.Name ='Test'; 
        opp.AccountID = accId;
        opp.Type = 'New';
        opp.CloseDate = System.today();
        opp.StageName = Stagename;
        
        insert opp;
        
        return opp.Id;
    }

    public static Id createProduct2(){
        Product2 prod = new Product2(
            Name = 'Product X',
            ProductCode = 'Pro-X',
            isActive = true
        );
        
        insert prod;
        
        return prod.Id;
    }

    public static Id createPricebookEntry(Id productId){
        PricebookEntry standardPriceEntry = new PricebookEntry();
        standardPriceEntry.IsActive = true;
        standardPriceEntry.Product2Id = productId;
        standardPriceEntry.Pricebook2Id = Test.getStandardPricebookId();
        standardPriceEntry.UnitPrice = 10;
        standardPriceEntry.UseStandardPrice = false;
        insert standardPriceEntry;
        
        return standardPriceEntry.Id;
    }

    public static Id createOppLineItem(Id oppId, Id priceBookEntryId, String oppStatus){
        OpportunityLineItem  oppLineItem = new OpportunityLineItem();
        oppLineItem.OpportunityId = oppId;
        oppLineItem.Quantity = 1;
        oppLineItem.PricebookEntryId = priceBookEntryId;
        oppLineItem.TotalPrice = 100.00;
        insert oppLineItem;
        
        return oppLineItem.Id;
    }


    public static void createTestOpportunityContactRole(ID oppId, ID conId){
        OpportunityContactRole ContactRoleObj = new OpportunityContactRole();
        ContactRoleObj.ContactId = conId;
        ContactRoleObj.IsPrimary = true;
        ContactRoleObj.OpportunityId = oppId;
        
        insert ContactRoleObj;
    }

    public static void createTestOrder(ID accId){
        Order order = new Order(
            AccountId = accId,
            EffectiveDate = System.today(),
            Status = 'Draft',
            PriceBook2Id = Test.getStandardPricebookId()
        );
        insert order;
    }

    public static void createTestOrderLine(ID orderId, Id product2Id, Id pricebookEntryId){
        OrderItem lineItem = new OrderItem();
        lineItem.OrderId = orderId;
        lineItem.Quantity = 10;
        lineItem.UnitPrice = 240;
        lineItem.Product2id = product2Id;
        lineItem.PricebookEntryId = pricebookEntryId;
        insert lineItem;

        // Now update & Activate the Order
        Order order = new Order();
        order.Id = orderId;
        order.Status = 'Activated';
        update order;
    }
}

@isTest
public class OrderTest{

   @isTest 
   public void myUnitTest() {
        Account acc = TestDataFactory.createAccount();
        Contact cont = TestDataFactory.createContactForAccount(acc.id, 'test@g.com');
        Product2 pro = TestDataFactory.createProduct2();
        PricebookEntry standardPriceEntry = TestDataFactory.createPricebookEntry(pro.Id);
        Order order = TestDataFactory.createTestOrder(acc.Id);
        OrderItem lineItem = TestDataFactory.createTestOrderLine(order.Id, pro.Id, standardPriceEntry.Id);
   }

}