public void CantDeleteMembershipUser()
        {
            using (EF_ZMT_DbContext.EF_ZMT_DbContext context = new EF_ZMT_DbContext.EF_ZMT_DbContext())
            {
                context.Context.ExecuteStoreCommand("DELETE FROM MembershipUser");
                FixedAssetService transaction = new FixedAssetService();
                MembershipUser user = new MembershipUser()
                {
                    login = "******",
                    email = "*****@*****.**",
                    creation_date = DateTime.Now,
                    is_online = false,
                    name = "Jan",
                    surname = "Kowalski",
                    is_active = true,
                    last_login_date = DateTime.Now,
                    password = "******"
                };

                transaction.AddMembershipUser(user);
                Assert.AreEqual(context.Context.MembershipUsers.Count(), 1);
                user = context.Context.MembershipUsers.FirstOrDefault(x => x.login == "user123");
                transaction.DeleteMembershipUser(user);
                user = context.Context.MembershipUsers.FirstOrDefault(x => x.login == "user123");
                Assert.IsNull(user);
                Assert.AreEqual(context.Context.MembershipUsers.Count(), 0);
            }
        }