How to test DAL implemented using linq2sql and Repository pattern? - unit-testing

Question

Here is a part of my DAL.
DataContext interface:
public interface IDataContextFactory
{
System.Data.Linq.DataContext Context { get; }
void SaveAll();
}
Here is my data context class which contains generated classes:
partial class InternetRailwayTicketSalesDataContext: DataContext, IDataContextFactory
{
public System.Data.Linq.DataContext Context
{
get { return this; }
}
public void SaveAll()
{
this.SubmitChanges();
}
}
Here is my Repository interface:
public interface IRepository<T> where T : class
{
/// <summary>
/// Return all instances of type T.
/// </summary>
/// <returns></returns>
IEnumerable<T> GetAll();
}
Here is my Repository interface implementation:
public class Repository<T> : IRepository<T> where T : class
{
protected IDataContextFactory _dataContextFactory;
/// <summary>
/// Return all instances of type T.
/// </summary>
/// <returns></returns>
public IEnumerable<T> GetAll()
{
return GetTable;
}
private System.Data.Linq.Table<T> GetTable
{
get { return _dataContextFactory.Context.GetTable<T>(); }
}
}
Here is an interface for concrete repository class:
interface IPasswayRepository
{
bool IsPasswayExists(int id);
}
And finally here is a concrete repository class implementation:
class PasswayRepository:Repository<Passway>, IPasswayRepository
{
public PasswayRepository(IDataContextFactory context)
: base(context)
{
}
public bool IsPasswayExists(int id)
{
if (GetAll().Where(pass => pass.Id == id && pass.IsDeleted == false).Count() > 0)
return true;
else
return false;
}
}
Can you give me an example of how to test IsPasswayExists method? (you can use any mock framework if you want to).