Fluent NHibernate, One-to-many with Orphan Delete

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using NHibernate;
using FluentNHibernate.Mapping;
using NUnit.Framework;

namespace NStackExample.Data.Tests
{

public class Parent : Entity
{

private ICollection m_Children = new HashSet();

public virtual ICollection Children
{
get { return m_Children; }
protected set { m_Children = value; }
}

}

public class Child : Entity
{

private Parent m_Parent;

public virtual Parent Parent
{
get { return m_Parent; }
set { m_Parent = value; }
}

}

public class ParentMapping : ClassMap
{
public ParentMapping()
{
Id((Parent x) => x.ID).GeneratedBy.GuidComb();
HasMany((Parent x) => x.Children)
.AsSet()
.WithForeignKeyConstraintName("ParentChildren")
.Cascade.AllDeleteOrphan()
.Inverse();
}
}

public class ChildMapping : ClassMap
{
public ChildMapping()
{
Id((Child x) => x.ID).GeneratedBy.GuidComb();
References((Child x) => x.Parent)
.Cascade.All()
.WithForeignKey("ChildParent")
.Not.Nullable();
}
}

[TestFixture()]
public class ParentMappingTests
{

[Test()]
public void CanCascadeSaveFromParentToChild()
{
Guid ID;
Parent P;
Child C;
using (SQLiteDatabaseScope Scope = new SQLiteDatabaseScope())
{
using (ISession Session = Scope.OpenSession())
{
using (ITransaction Tran = Session.BeginTransaction())
{
P = new Parent();

//Add a child of the parent
C = new Child { Parent = P };
P.Children.Add(C);

ID = (Guid) Session.Save(P);
Tran.Commit();
}
Session.Clear();

using (ITransaction Tran = Session.BeginTransaction())
{

P = Session.Get(ID);

Assert.IsNotNull(P);
Assert.AreEqual(ID, P.ID);

Assert.AreEqual(1, P.Children.Count);
Assert.AreNotSame(C, P.Children.First());
Assert.AreEqual(C.ID , P.Children.First().ID );
Assert.AreSame(P.Children.First().Parent, P);

Tran.Commit();

}
}

}
}

[Test()]
public void CanDeleteOrphanFromParentToChildren()
{
Guid ID;
Parent P;
Child C;
using (SQLiteDatabaseScope Scope = new SQLiteDatabaseScope())
{
using (ISession Session = Scope.OpenSession())
{
using (ITransaction Tran = Session.BeginTransaction())
{
P = new Parent();

//Add a child of the parent
C = new Child { Parent = P };
P.Children.Add(C);

ID = (Guid) Session.Save(P);
Tran.Commit();
}
Session.Clear();

using (ITransaction Tran = Session.BeginTransaction())
{

P = Session.Get(ID);

Assert.IsNotNull(P);
Assert.AreEqual(ID, P.ID);

Assert.AreEqual(1, P.Children.Count);
Assert.AreNotSame(C, P.Children.First());
Assert.AreEqual(C.ID, P.Children.First().ID );
Assert.AreSame(P.Children.First().Parent, P);

Tran.Commit();
}
Session.Clear();

//Orphan the child
C = P.Children.First();
P.Children.Remove(C);
C.Parent = null;

using (ITransaction Tran = Session.BeginTransaction())
{
//Orhpaned child should be deleted
Session.SaveOrUpdate(P);
Tran.Commit();
}
Session.Clear();

using (ITransaction Tran = Session.BeginTransaction())
{
P = Session.Get(ID);

Assert.AreEqual(0, P.Children.Count);

Tran.Commit();

}
}
}
}

}

}