public void IsNotNull()
{
ICriteriaBuilder cb = EJBContainer.Instance.EntityManager.GetCriteriaBuilder();
ICriteriaQuery cq = cb.CreateQuery();
IRoot r = cq.From("Students");
IPredicate exp = cb.IsNotNull(r.Get("LastName"));
Assert.AreEqual("Students.LastName IS NOT NULL", exp.ExpressionValue);
}