正确的ASP单元测试.净MVC5

我已经得到了以下代码，我不知道我已经为这些方法写出了哪些适当的单元测试，以及如何完成。基本上我想用nunit。framework。

提前感谢你的任何线索!

   [AllowAnonymous]
        public ActionResult ForgotPassword(string id)
        {
            var model = new ForgotPasswordViewModel();
            if (!string.IsNullOrEmpty(id))
            {
                #region Process Reset Password Key
                try
                {
                    var forgotPasswordEvent = AppModel.ForgotPasswordEvents.SingleOrDefault(x => x.UIDHash == id);
                    if (forgotPasswordEvent != null)
                    {
                        var stringToHash = string.Format("{0}---{1}---{2}", forgotPasswordEvent.UID.ToString(),
                                    forgotPasswordEvent.UserId.ToString(), forgotPasswordEvent.Created.ToString());
                        var readyHash = SecurityHelper.GetHashString(stringToHash);
                        if (id == readyHash)
                        {
                            var forgotPasswordEventUserId = forgotPasswordEvent.UserId.ToString();
                            var realUser = AppModel.AspNetUsers.SingleOrDefault(x => x.Id == forgotPasswordEventUserId);
                            if (realUser != null)
                            {
                                var resetPasswordViewModel = new ResetPasswordViewModel();
                                resetPasswordViewModel.ResetPasswordData = id;
                                resetPasswordViewModel.UserName = realUser.UserName;
                                return RedirectToAction("ResetPassword", "Account", resetPasswordViewModel); // ResetPassword(resetPasswordViewModel);
                            }
                        }
                    }
                    else
                    {
                        return RedirectToAction("Index", "Home");
                    }
                }
                catch (Exception)
                {
                }
                #endregion
            }
            #region Check if the user is logged in and fill out fileds for him.
            var sessionManager = SessionWrapper.GetFromSession<SessionManager>("_SessionManager");
            if (sessionManager != null)
            {
                var clientId = sessionManager.AppUser.ClientId;
                if (clientId != null)
                {
                    model.Email = sessionManager.AppUser.EmailID;
                    model.UserName = sessionManager.AppUser.UserName;
                    model.IsLoggedInUser = true;
                }
            }
            #endregion
            return View(model);
        }
        [HttpPost]
        [AllowAnonymous]
        public ActionResult ForgotPassword(ForgotPasswordViewModel model, FormCollection formCollection)
        {
            if (ModelState.IsValid)
            {
                try
                {
                    #region Check user input
                    var user = AppModel.AspNetUsers.SingleOrDefault(x => x.UserName == model.UserName);
                    var areErrors = false;
                    if (user == null)
                    {
                        ModelState.AddModelError("UserDoesnotExist", DLMModelEntities.Properties.Resource.UserDoesNotExist);
                        areErrors = true;
                    }
                    if (user.EmailID != model.Email)
                    {
                        ModelState.AddModelError("EmailIsWrong", DLMModelEntities.Properties.Resource.EmailIsWrong);
                        areErrors = true;
                    }
                    if (areErrors)
                        return View(model);
                    #endregion
                    #region Send Email and inform user
                    try
                    {
                        var forgotPasswordEvent = new ForgotPasswordEvent();
                        var resetPasswordEmailUserState = new ResetPasswordEmailUserState();
                        resetPasswordEmailUserState.ForgotPasswordEventId = Guid.NewGuid();
                        resetPasswordEmailUserState.UserId = Guid.Parse(user.Id);
                        resetPasswordEmailUserState.Created = DateTime.Now;
                        forgotPasswordEvent.UID = resetPasswordEmailUserState.ForgotPasswordEventId;
                        forgotPasswordEvent.UserId = resetPasswordEmailUserState.UserId;
                        forgotPasswordEvent.IsSent = false;
                        forgotPasswordEvent.Created = resetPasswordEmailUserState.Created;
                        var stringToHash = string.Format("{0}---{1}---{2}", resetPasswordEmailUserState.ForgotPasswordEventId.ToString(),
                             resetPasswordEmailUserState.UserId.ToString(), resetPasswordEmailUserState.Created.ToString());
                        forgotPasswordEvent.UIDHash = SecurityHelper.GetHashString(stringToHash);
                        AppModel.ForgotPasswordEvents.Add(forgotPasswordEvent);
                        AppModel.SaveChanges();
                        var smtp = (SmtpSection)ConfigurationManager.GetSection("system.net/mailSettings/smtp");
                        // Set the MailerModel properties that will be passed to the MvcMailer object.
                        var m = new MailerModel();
                        m.UserName = user.UserName;
                        m.ResetPasswordLink = string.Format("{0}/{1}", Request.Url.AbsoluteUri, forgotPasswordEvent.UIDHash);
                        m.FromEmail = smtp.From;
                        m.Subject = AppConfiguration.ResetEmailSubject;
                        m.ToEmail = model.Email;                     
                        var client = new SmtpClientWrapper();
                        client.SendCompleted += (sender, e) =>
                        {
                            if (e.Error != null || e.Cancelled)
                            {
                                // Handle Error                                
                            }
                            else
                            {
                                try
                                {
                                    var forgotPasswordEventsToUpdate = AppModel.ForgotPasswordEvents.SingleOrDefault(x => x.UID == resetPasswordEmailUserState.ForgotPasswordEventId);
                                    if (forgotPasswordEventsToUpdate != null)
                                    {
                                        forgotPasswordEventsToUpdate.IsSent = true;
                                        AppModel.SaveChanges();
                                    }
                                }
                                catch (Exception ex)
                                {                                    
                                    ModelState.AddModelError("EmailEx", ex.Message);
                                }
                            }
                        };
                        Mailer.PasswordReset(m).SendAsync(resetPasswordEmailUserState, client);
                        model.IsResetEMailSent = true;
                    }
                    catch (Exception ex)
                    {
                        ModelState.AddModelError("EmailEx", ex.Message);
                    }
                    #endregion
                }
                catch (Exception ex)
                {
                    ModelState.AddModelError("EmailEx", ex.Message);
                }
            }
            return View(model);
        }