class CustomSaveInterceptorAddsChildren : EntityServerSaveInterceptor {

    protected override bool ExecuteSave() {

      var customers = this.EntityManager.FindEntities<Customer>(EntityState.AnyAddedModifiedOrDeleted);
      if (customers.Count() > 0) {
        var aCustomer = customers.First();
        var anOrder = new Order();
        anOrder.ShipName = "TestShip";
        aCustomer.Orders.Add(anOrder);
      }

      return base.ExecuteSave();
    }
  }

    var em = new DomainModelEntityManager();

      var aCustomer = CreateNewCustomer(em);
      DoAsyncAction(() => {
        em.SaveChangesAsync(op => {
          Assert.IsTrue(op.CompletedSuccessfully);

          //var savedCustomer = em.FindEntities<Customer>(EntityState.AllButDetached).First();
          //var savedOrder = em.FindEntities<Order>(EntityState.AllButDetached).First();

          var savedCustomer = op.Entities.OfType<Customer>().First();
          var savedOrder = op.Entities.OfType<Order>().First();

          Assert.IsTrue(savedCustomer.Orders.First().OrderID == savedOrder.OrderID);
          Assert.IsTrue(savedOrder.CustomerID == savedCustomer.CustomerID);

          var oldShipName = savedOrder.ShipName;
          savedOrder.ShipName += DateTime.Now.Millisecond.ToString();
          savedOrder.EntityAspect.RejectChanges();
          Assert.IsTrue(savedOrder.ShipName == oldShipName);

          var newShipName = savedOrder.ShipName + DateTime.Now.Millisecond.ToString();
          savedOrder.ShipName = newShipName;
          em.SaveChangesAsync(op2 => {
            Assert.IsTrue(op2.CompletedSuccessfully);
            var theSavedOrder = (Order)op2.Entities.First();
            Assert.IsTrue(theSavedOrder.ShipName == newShipName);
            Exit();
          });
        });
      });