c# - Unit test fluent nhibernate repository with in memory sql lite - no such table error

Question

I'm trying to write unit tests for a repository pattern using Fluent NHibernate. I chose to use an in-memory sqlite database in order to avoid sql server access (which can be done for integration tests).

Here are the classes I used:

public enum ExpenseCategory
{
    Eat,
    Clothes,
    Car,
    Leisure,
    Rent,
    House,
    Lecture,
    Trip,
    Restaurent
}

public class Expense
{
    public virtual int Id { get; set; }
    public virtual ExpenseCategory Category { get; set; }
    public virtual double Amount { get; set; }
    public virtual bool IsNecessary { get; set; }
    public virtual bool IsPeriodic { get; set; }
    public virtual string Comment { get; set; }
}

    public ExpenseMapping()
    {
        Table("Expense");
        Id(x => x.Id).Column("idexpense");
        Map(x => x.Category).Column("category");
        Map(x => x.Amount).Column("amount");
        Map(x => x.IsNecessary).Column("isnecessary");
        Map(x => x.IsPeriodic).Column("isperiodic");
        Map(x => x.Comment).Column("comment");
    }
    interface IRepository<T>
{
    T GetById(int id);
    void SaveOrUpdate(T entity);
    void Delete(T entity);
    List<T> GetAll();
}

public interface IDatabase
{
    Configuration Config { get; set; }
    ISessionFactory Session { get; set; }
}

public class NhibernateRepository<T> : IRepository<T>
{
    private readonly Configuration _configuration;
    private readonly ISessionFactory _session;

    public NhibernateRepository(IDatabase database)
    {
        _configuration = database.Config;
        _session = database.Session;

    }

    public T GetById(int id)
    {
        T retrievedObject;
        using (var session = _session.OpenSession())
        {
            using (var transaction = session.BeginTransaction())
            {
                retrievedObject = session.Get<T>(id);
                transaction.Commit();
            }
        }
        return retrievedObject;
    }

    public void SaveOrUpdate(T entity)
    {
        using (var session = _session.OpenSession())
        {
            using (var transaction = session.BeginTransaction())
            {
                session.SaveOrUpdate(entity);
                transaction.Commit();
            }
        }
    }

    public void Delete(T entity)
    {
        using (var session = _session.OpenSession())
        {
            using (var transaction = session.BeginTransaction())
            {
                session.Delete(entity);
                transaction.Commit();
            }
        }
    }

    public List<T> GetAll()
    {
        IList<T> allObjects;
        using (var session = _session.OpenSession())
        {
            using (var transaction = session.BeginTransaction())
            {
                allObjects = session.CreateCriteria(typeof (T)).List<T>();
                transaction.Commit();
            }
        }

        return (List<T>)allObjects;
    }
}


public class DatabaseSqlLite : IDatabase, IDisposable
{
    public Configuration Config { get; set; }
    public ISessionFactory Session { get; set; }

    public DatabaseSqlLite()
    {
        Session = Fluently.Configure()
            .Database(SQLiteConfiguration.Standard.InMemory().ShowSql())
            .Mappings(m => m.FluentMappings
                            .Add(typeof(ExpenseMapping))
                      )
            .ExposeConfiguration(x => Config = x)
            .BuildSessionFactory();

        SchemaExport export = new SchemaExport(Config);
        export.Execute(true, true, false, Session.OpenSession().Connection, null);

    }

    public void Dispose()
    {
        //S.Dispose();
    }
}

public class DatabaseSqlServer : IDatabase
{
    public Configuration Config { get; set; }
    public ISessionFactory Session { get; set; }

    public DatabaseSqlServer()
    {
       Config = Fluently.Configure()
       .Database(MsSqlConfiguration.MsSql2008
                    .ConnectionString(m => m.Server(@".\SqlExpress")
                    .Database("databasename")
                    .TrustedConnection()))
                .Mappings(m => m.FluentMappings.AddFromAssembly(Assembly.GetExecutingAssembly()))
                .BuildConfiguration();

       Session = Config.BuildSessionFactory();
    }
}

Using DatabaseSqlServer class from a console application gives me correct results. Trying to unit test using DatabaseSqlLite class gives me errors:

public class RespositoryTest
{
    [Fact]
    public void InsertAndLoadExpense()
    {
        var database = new DatabaseSqlLite();

        var repository = new NhibernateRepository<Expense>(database);

        var expense = new Expense()
            {
                Amount = 3,
                IsNecessary = true,
                IsPeriodic = true,
                Category = ExpenseCategory.Car
            };
        repository.SaveOrUpdate(expense);
        Assert.Equal(1, repository.GetAll().Count);
    }
}

Errors:

PRAGMA foreign_keys = OFF

drop table if exists Expense

PRAGMA foreign_keys = ON

create table Expense (
    idexpense  integer primary key autoincrement,
   category TEXT,
   amount DOUBLE,
   isnecessary BOOL,
   isperiodic BOOL,
   comment TEXT
)

NHibernate: INSERT INTO Expense (category, amount, isnecessary, isperiodic, comment) VALUES (@p0, @p1, @p2, @p3, @p4); select last_insert_rowid();@p0 = 'Car' [Type: String (0)], @p1 = 3 [Type: Double (0)], @p2 = True [Type: Boolean (0)], @p3 = True [Type: Boolean (0)], @p4 = NULL [Type: String (0)]

NHibernate.Exceptions.GenericADOException could not insert: [MoneyManagerCore.Expense][SQL: INSERT INTO Expense (category, amount, isnecessary, isperiodic, comment) VALUES (?, ?, ?, ?, ?); select last_insert_rowid()] à NHibernate.Id.Insert.AbstractReturningDelegate.PerformInsert(SqlCommandInfo insertSQL, ISessionImplementor session, IBinder binder) à NHibernate.Persister.Entity.AbstractEntityPersister.Insert(Object[] fields, Boolean[] notNull, SqlCommandInfo sql, Object obj, ISessionImplementor session) à NHibernate.Persister.Entity.AbstractEntityPersister.Insert(Object[] fields, Object obj, ISessionImplementor session) à NHibernate.Action.EntityIdentityInsertAction.Execute() à NHibernate.Engine.ActionQueue.Execute(IExecutable executable) à NHibernate.Event.Default.AbstractSaveEventListener.PerformSaveOrReplicate(Object entity, EntityKey key, IEntityPersister persister, Boolean useIdentityColumn, Object anything, IEventSource source, Boolean requiresImmediateIdAccess) à NHibernate.Event.Default.AbstractSaveEventListener.PerformSave(Object entity, Object id, IEntityPersister persister, Boolean useIdentityColumn, Object anything, IEventSource source, Boolean requiresImmediateIdAccess) à NHibernate.Event.Default.AbstractSaveEventListener.SaveWithGeneratedId(Object entity, String entityName, Object anything, IEventSource source, Boolean requiresImmediateIdAccess) à NHibernate.Event.Default.DefaultSaveOrUpdateEventListener.SaveWithGeneratedOrRequestedId(SaveOrUpdateEvent event) à NHibernate.Event.Default.DefaultSaveOrUpdateEventListener.EntityIsTransient(SaveOrUpdateEvent event) à NHibernate.Event.Default.DefaultSaveOrUpdateEventListener.PerformSaveOrUpdate(SaveOrUpdateEvent event) à NHibernate.Event.Default.DefaultSaveOrUpdateEventListener.OnSaveOrUpdate(SaveOrUpdateEvent event) à NHibernate.Impl.SessionImpl.FireSaveOrUpdate(SaveOrUpdateEvent event) à NHibernate.Impl.SessionImpl.SaveOrUpdate(Object obj) à MoneyManagerRepository.NhibernateRepository`1.SaveOrUpdate(T entity) dans NhibernateRepository.cs: line 56 à UnitTests.RespositoryTest.InsertAndLoadExpense() dans RespositoryTest.cs: line 28 System.Data.SQLite.SQLiteException SQL logic error or missing database no such table: Expense

Can anyone help me to resolve this?