public void ConcurrencyTests()
{
//Get the same record but loaded from two separate contexts so the tracking won't overlap.
ICustomerRepository repository = new CustomerRepository(_dbContext);
var secondContext = new EntityContext();
//add new customer to db.
var newCustomer = CreateCustomer(repository);
//load this customer from context 1
var firstCustomer1 = repository.GetById(newCustomer.CustomerId);
firstCustomer1.City = "newCity3";
//load the same customer from context 2
ICustomerRepository secondRepository = new CustomerRepository(secondContext);
var firstCustomer2 = secondRepository.GetById(firstCustomer1.CustomerId);
//Check the states
Debug.WriteLine(_dbContext.Entry(newCustomer).State);
Debug.WriteLine(_dbContext.Entry(firstCustomer1).State);
Debug.WriteLine(secondContext.Entry(firstCustomer2).State);
//Modify the second customer. We have the same TimeStamp as the original record
//however the timestamp in the database would've been updated already.
firstCustomer2.Address = "222 main st" + DateTime.Now.ToString();
Debug.WriteLine(secondContext.Entry(firstCustomer2).State);
//This should update that customer.
repository.Update(firstCustomer1);
repository.Save();
//This should throw an exception.
secondRepository.Update(firstCustomer2);
secondRepository.Save();
secondContext.Dispose();
}