Retrieve data from MockRepository? - unit-testing

Question

I'm new to Unit Testing and I'm using Rhino Mock in ASP.NET MVC
I have created a main test class with this code :
[TestFixture]
public class PersistenceTest
{
[Test]
protected T SaveAndLoadEntity<T>(T entity) where T : BaseEntity
{
var mockDataSource = MockRepository.GenerateMock<IRepository<T>>();
mockDataSource.Add(entity);
var fromDb = mockDataSource.FindBy(entity.Id);
return fromDb;
}
}
and create a customer test class like this :
[TestFixture]
public class CustomerTests : PersistenceTest
{
[Test]
public void Can_Save_And_Load_Customer()
{
var customer = new Customer()
{
Id = 12,
Name = "Reza",
Family = "Pazooki",
Company = "Rozaneh",
Email = "ipazooki#gmail.com",
Mobile = "09352463668",
Fax = "021-44869059",
Tel = "021-44869059",
WebSite = "www.rozanehmedia.com"
};
var fromDb = SaveAndLoadEntity(customer);
fromDb.ShouldNotBeNull();
}
}
but when run the code, it says that return value from Database is NULL!!!
I don't know what is wrong with my code but I save and retrieve data from mock repository and it seems every thing is ok.
tnx form any help in forward :)

Answer 1

Mocks are used to record invocations on objects for further verification or to provide values when called (later behavior requires setup).
In your SaveAndLoadEntity method you make calls to mock (Add and FindBy). Since mock is a fake object with no real behavior, those calls do nothing (they don't save nor extract any entities to/from database).
If you want to test persistence layer you should be doing tests against real database instance (or optionally, in-memory one).
// [Test] attribute is not needed
protected T SaveAndLoadEntity<T>(T entity) where T : BaseEntity
{
var dataSource = new DataSource("connection string");
dataSource.Add(entity);
var fromDb = dataSource.FindBy(entity.Id);
return fromDb;
}
At the moment you are making calls to not-setup mock which doesn't achieve anything.

Answer 2

Thank you jimmy_keen.
I change my code according to your advice like this and it worked great :)
[TestFixture]
public class PersistenceTest
{
protected ISession Session;
protected ITransaction Transaction;
[SetUp]
public void SetUp()
{
var helper = new NHibernateHelper("...connectionString....");
Session = helper.SessionFactory.OpenSession();
Transaction = Session.BeginTransaction();
}
protected T SaveAndLoadEntity<T>(T entity) where T : BaseEntity
{
Session.Save(entity);
Transaction.Commit();
var fromDb = Session.Get<T>(entity.Id);
return fromDb;
}
}