奇怪的NHibernate Sqllite.InMemory行为

Question

I am trying to setup database unit tests using the Sqllite.InMemory functionality. If I run an unit test, everything is working fine. If I run the same test a second time I get an System.Data.SQLite.SQLiteException: no such table: Person

After waiting for a while and/or (?) restarting Visual studio I can run the unit test once again.

Is there something wrong with the configuration or the session handling?

public abstract class InMemoryDatabaseFixture : IDisposable
{
    private const string ConnectionString
        = "Data Source=:memory:;Version=3;New=True;Pooling=True;Max Pool Size=1;";

    private readonly ISessionFactory _sessionFactory;
    private readonly ISession _session;

    protected InMemoryDatabaseFixture()
    {
        var config = SQLiteConfiguration.Standard.InMemory().ShowSql().ConnectionString(ConnectionString);
        _sessionFactory = Fluently.Configure()
            .Database(config)
            .Mappings(m => m.FluentMappings.AddFromAssemblyOf<SessionContainer>())
            .ExposeConfiguration(cfg => new SchemaUpdate(cfg).Execute(true, true))
            .BuildSessionFactory();

        _session = _sessionFactory.OpenSession();

        SessionContainer = MockRepository.GenerateMock<ISessionContainer>();
        SessionContainer.Stub(sc => sc.SessionFactory).Return(_sessionFactory);
        SessionContainer.Stub(sc => sc.Session).Return(_session);
    }

    protected ISessionContainer SessionContainer { get; private set; }

    public void Dispose()
    {
        _sessionFactory.Dispose();
        _session.Dispose();
    }
}

Here a simple usage of the base class:

[TestFixture]
public class FinderFixture : InMemoryDatabaseFixture
{
    [Test]
    public void Test()
    {
        var finder = new Finder(SessionContainer);

        var result = finder.Find();

        Assert.That(result, Is.Not.Null);
    }
}

---

Update : After some trials here is finally my working configuration. Exporting the schema after building the SessionFactory is doing the magic.

Configuration configuration = null;
_sessionFactory = Fluently.Configure()
    .Database(SQLiteConfiguration.Standard.InMemory().ShowSql())
    .ExposeConfiguration(cfg => configuration = cfg)
    .Mappings(m => m.FluentMappings.AddFromAssemblyOf<SessionContainer>())
    .BuildSessionFactory();

_session = _sessionFactory.OpenSession();
var export = new SchemaExport(configuration);
export.Execute(true, true, false, _session.Connection, null);

Answer 1

You have requested that connection pooling in the ADO.NET provider be enabled. This will keep the underlying connection active even after NHibernate has closed it.

In my own unit tests, I have simply (based on your original code):

_sessionFactory = Fluently.Configure()
        .Database(SQLiteConfiguration.Standard.InMemory())
        .Mappings(m => m.FluentMappings.AddFromAssemblyOf<SessionContainer>())
        .ExposeConfiguration(cfg => new SchemaUpdate(cfg).Execute(true, true))
        .BuildSessionFactory();

Also, since the session is generated from the session factory, it would be prudent to dispose all sessions before disposing the session factory.