Linq to Sql Adding Two Records for a Single User

Question

I am going nuts here! I am trying to figure out that why my UserRepository.Save method is inserting two records for the same user.

Here is the code:

 [TestFixture]
    public class foo
    {
        private IUserRepository _userRepository;
        private IRoleRepository _roleRepository;
        private User _user; 

        [SetUp]
        public void ini()
        {
            EStudy.Domain.Model.Configuration.StructureMapConfiguration.Configure();

            _userRepository = ObjectFactory.GetInstance<IUserRepository>();
            _roleRepository = ObjectFactory.GetInstance<IRoleRepository>(); 

            _user = new User()
            {
                FirstName = "Mohammad",
                LastName = "Azam",
                UserName = "azamsharp",
                Password = "password",
                Active = true,
                DateCreated = DateTime.Now,
                DateModified = DateTime.Now,
                Email = "[email protected]",
            };

        }

        [Test]
        public void boo()
        {
            _user.AddRole(_roleRepository.GetByName("Student"));
            _userRepository.Save(_user); 
            Assert.IsTrue(_user.UserId > 0); 
        }


    }

updated: The simplest test that is failing. The test boo fails.