Felbook.Models.MessageService.SendMessageToUsers C# (CSharp) Метод

        public void SendMessageToUsers(User sender, ISet<User> recievers, Message prevMessage, string text)
        {
            Message msg = new Message();
            msg.Created = DateTime.Now;
            msg.Sender = sender;
            msg.ReplyTo = prevMessage;
            msg.Text = text;
            //msg.Readers.Add(sender);

            foreach (var reciever in recievers)
            {
                msg.Recievers.Add(reciever);
            }

            db.MessageSet.AddObject(msg);
            db.SaveChanges();
        }

        public void SendMessageToUsersTest()
        {
            FelBookDBEntities DbEntities = new FelBookDBEntities();
            MessageService target = new MessageService(DbEntities);

            User mockSender = User.CreateUser(0, "test", "test",
                DateTime.Now, "mail", "sender", "");
            DbEntities.UserSet.AddObject(mockSender);
            User mockReciever = User.CreateUser(0, "test", "test",
                DateTime.Now, "mail", "reciever", "");
            DbEntities.UserSet.AddObject(mockReciever);
            DbEntities.SaveChanges();

            ISet<User> recievers = new HashSet<User>();
            recievers.Add(mockReciever);
            Message prevMessage = null;
            string text = "some text";
            target.SendMessageToUsers(mockSender, recievers, prevMessage, text);

            Message message1 = DbEntities.MessageSet.Single(m => m.Sender.Username == mockSender.Username);
            Assert.AreEqual(mockSender, message1.Sender);
            Assert.IsTrue(message1.Recievers.Contains(mockReciever));
            Assert.AreEqual(text, message1.Text);
            Assert.IsNull(message1.ReplyTo);

            recievers = new HashSet<User>();
            recievers.Add(mockSender);
            prevMessage = message1;
            text = "some other text";
            target.SendMessageToUsers(mockReciever, recievers, prevMessage, text);

            Message message2 = DbEntities.MessageSet.Single(m => m.Sender.Username == mockReciever.Username);
            Assert.AreEqual(mockReciever, message2.Sender);
            Assert.IsTrue(message2.Recievers.Contains(mockSender));
            Assert.AreEqual(text, message2.Text);
            Assert.AreEqual(message1, message2.ReplyTo);

            DbEntities.MessageSet.DeleteObject(message2);
            DbEntities.MessageSet.DeleteObject(message1);
            DbEntities.UserSet.DeleteObject(mockReciever);
            DbEntities.UserSet.DeleteObject(mockSender);
            DbEntities.SaveChanges();
        }