public void TestForeignKeyInterceptors()
{
    var em = new EntityManager(shouldConnect: false);

    //Make an order
    var order = em.CreateEntity<Order>();
    order.EntityAspect.AddToManager();

    //Make a customer - and generate a new ID for it
    var customer = em.CreateEntity<Customer>();
    customer.CustomerID = Guid.NewGuid();
    customer.EntityAspect.AddToManager();

    //The CustomerID field should currently be NULL
    var originalCustomerId = order.CustomerID;
    Assert.IsNull(originalCustomerId);

    //Various bools used to see what things get fired
    var propertyChangeFired = false;
    var afterSetFired = false;
    var beforeSetFired = false;

    //Add before and after set interceptors to the CustomerID field
    Order.PropertyMetadata.CustomerID.SetterInterceptor.AddAction(
        PropertyInterceptorTiming.After,
        args => { afterSetFired = true; });

    Order.PropertyMetadata.CustomerID.SetterInterceptor.AddAction(
        PropertyInterceptorTiming.Before,
        args => { beforeSetFired = true; });

    //Also watch for property change notifications
    order.PropertyChanged += (s, e) =>
        {
            if (e.PropertyName == "CustomerID")
                propertyChangeFired = true;
        };

    //Assign the customer entity - this will trigger the Customer and CustomerID fields to get changed
    order.Customer = customer;

    //Verify that the CustomerID did in fact get updated
    var newCustomerId = order.CustomerID;
    Assert.AreEqual(customer.CustomerID, newCustomerId);
    Assert.AreNotEqual(originalCustomerId, newCustomerId);

    //Now see what things got fired

    //PropertyChanged event is raised
    Assert.IsTrue(propertyChangeFired); 

    //But before and after set interceptors don't.  These next two tests will fail.
    Assert.IsTrue(afterSetFired); //Fails
    Assert.IsTrue(beforeSetFired);//Fails
}