Object Graph State(s) while Disconnected or Between different DataContext(s)

Note: The following are typically injected: IRepositoryProvider, IDataContextAsync, IDataContextAsync, IRepository, IRepositoryAsync vs. manually instantiated as they are in the code samples below.

// Create new customer
using (IDataContextAsync context = new NorthwindContext())
using (IUnitOfWorkAsync unitOfWork = new UnitOfWork(context, _repositoryProvider))
{
    IRepositoryAsync<Customer> customerRepository = new Repository<Customer>(context, unitOfWork);

    var customerForInsertGraphTest = new Customer
    {
        CustomerID = "LLE38",
        CompanyName = "CBRE",
        ContactName = "Long Le",
        ContactTitle = "App/Dev Architect",
        Address = "11111 Sky Ranch",
        City = "Dallas",
        PostalCode = "75042",
        Country = "USA",
        Phone = "(222) 222-2222",
        Fax = "(333) 333-3333",
        ObjectState = ObjectState.Added,
        Orders = new[]
        {
            new Order()
            {
                CustomerID = "LLE38",
                EmployeeID = 1,
                OrderDate = DateTime.Now,
                ObjectState = ObjectState.Added,
            }, 
            new Order()
            {
                CustomerID = "LLE39",
                EmployeeID = 1,
                OrderDate = DateTime.Now,
                ObjectState = ObjectState.Added
            }, 
        }
    };

    customerRepository.InsertOrUpdateGraph(customerForInsertGraphTest);
    unitOfWork.SaveChanges();
}

Customer customerForUpdateDeleteGraphTest = null;

            //  Query for newly created customer by ID from a new context, to ensure it's not pulling from cache
using (IDataContextAsync context = new NorthwindContext())
using (IUnitOfWorkAsync unitOfWork = new UnitOfWork(context, _repositoryProvider))
{
    IRepositoryAsync<Customer> customerRepository = new Repository<Customer>(context, unitOfWork);
                
        customerForUpdateDeleteGraphTest = customerRepository
        .Query(x => x.CustomerID == "LLE38")
        .Include(x => x.Orders)
        .Select()
        .SingleOrDefault();

    // Testing that customer was created
    Assert.AreEqual(customerForUpdateDeleteGraphTest.CustomerID, "LLE38");

    // Testing that orders in customer graph were created
    Assert.IsTrue(customerForUpdateDeleteGraphTest.Orders.Count == 2);

    // Make changes to the object graph while in this context, will save these 
    // changes in another context, testing managing states between and/or while disconnected
    // from the orginal DataContext

    // Updating the customer in the graph
    customerForUpdateDeleteGraphTest.City = "Houston";
    customerForUpdateDeleteGraphTest.ObjectState = ObjectState.Modified;

    // Updating the order in the graph
    var firstOrder = customerForUpdateDeleteGraphTest.Orders.Take(1).Single();
    firstOrder.ShipCity = "Houston";
    firstOrder.ObjectState = ObjectState.Modified;

    // Deleting one of the orders from the graph
    var secondOrder = customerForUpdateDeleteGraphTest.Orders.Skip(1).Take(1).Single();
    secondOrder.ObjectState = ObjectState.Deleted;
}

//  Query for newly created customer by ID from a new context, to ensure it's not pulling from cache
using (IDataContextAsync context = new NorthwindContext())
using (IUnitOfWorkAsync unitOfWork = new UnitOfWork(context, _repositoryProvider))
{
    IRepositoryAsync<Customer> customerRepository = new Repository<Customer>(context, unitOfWork);

    // Testing changes to graph while disconncted from it's orginal DataContext
    // Saving changes while graph was previous DataContext that was already disposed
    customerRepository.InsertOrUpdateGraph(customerForUpdateDeleteGraphTest);
    unitOfWork.SaveChanges();

    customerForUpdateDeleteGraphTest = customerRepository
        .Query(x => x.CustomerID == "LLE38")
        .Include(x => x.Orders)
        .Select()
        .SingleOrDefault();

    Assert.AreEqual(customerForUpdateDeleteGraphTest.CustomerID, "LLE38");

    // Testing for order(2) was deleted from the graph
    Assert.IsTrue(customerForUpdateDeleteGraphTest.Orders.Count == 1);

    // Testing that customer was updated in the graph
    Assert.IsTrue(customerForUpdateDeleteGraphTest.City == "Houston");

    // Testing that order was updated in the graph.
    Assert.IsTrue(customerForUpdateDeleteGraphTest.Orders.ToArray()[0].ShipCity == "Houston");
}