public void UpdatePurchaseTest()
        {
            IPurchaseRepository repo = new PurchaseRepository();

            //            IUnitOfWork unit = new UnitOfWork();
            //           IPurchaseRepository repo = new PurchaseRepository(unit);

            var header = repo.Single(x => x.VendorID == 1699);

            Assert.IsNotNull(header);

            header.VendorID = 1700;

            var details = header.PurchaseOrderDetails.Where(x => x.ProductID == 999).AsQueryable();
            Assert.IsNotNull(details);

            var detail = details.FirstOrDefault();
            detail.ProductID= 997;
            detail.OrderQty = 300;
            var newdet = new PurchaseOrderDetail();
            newdet.DueDate = DateTime.Now.Date;
            newdet.ModifiedDate = DateTime.Now.Date;
            newdet.LineTotal = 10;
            newdet.OrderQty = 10;
            newdet.ProductID = 999;
            newdet.PurchaseOrderID = header.PurchaseOrderID;
            newdet.ReceivedQty = 0;
            newdet.RejectedQty = 0;
            newdet.StockedQty = 0;
            newdet.UnitPrice = 10;
            header.PurchaseOrderDetails.Add(newdet);
            header.PurchaseOrderDetails.Add(new PurchaseOrderDetail()
            {
                DueDate = DateTime.Now.Date
                ,
                OrderQty = 25
                ,
                ProductID = 998
                ,
                UnitPrice = 600
                ,
                LineTotal = 700
                ,
                ReceivedQty = 25
                ,
                RejectedQty = 0
                ,
                StockedQty = 0
                ,
                ModifiedDate = DateTime.Now.Date
            });

            repo.Attach(header);

            header = repo.Single(x => x.VendorID == 1700);
            Assert.IsNotNull(header);

            details = header.PurchaseOrderDetails.Where(x => x.ProductID == 997).AsQueryable();
            Assert.IsNotNull(details);

            //var pocoDept = Mapper.Map<Department, dDepartment>(department);
            //return pocoDept;
        }