Testing Data Model in project that uses NHibernate for persistence

I'm still new with NHibernate, so correct me if I'm wrong on any of this.

When you are using NHibernate to build collections of objects 开发者_C百科from database records, NH takes care of instantiating your collections and populating them.

How do you instantiate your ISet collections when you are writing tests that don't actually use NH?

You can instantiate a field by using the constructor or by instantiating the field directly in the declaration. Classes mapped with NHibernate can be persistence ignorant.

public class MyEntity
{
   private readonly ISet<ChildEntity> children;

   public MyEntity()
   {
      children = new HashedSet<ChildEntity>();
   }

   public IEnumerable<ChildEntity> Children
   {
      get { return children; }
   }

   public void AddChild(Child child)
   {
     children.Add(child);
   }
}

Assuming you're testing something other than the data layer itself (like your domain logic, for example), you can simply create the objects yourself and populate them with test case data. Or you could be really sneaky and create a database with all your test cases.