public async Task CreateUserShouldSuccess()
        {
            User user = new User
            {
                UserId    = "*****@*****.**",
                FirstName = "sam",
                LastName  = "dsouza",
                Notes     = new List <Note>
                {
                    new Note {
                        Id = 1, Title = "Demo", Content = "NoSQL Document DB", CreationDate = DateTime.Now
                    }
                }
            };
            await noteRepository.AddUser(user);

            var result = noteRepository.GetUser("*****@*****.**");

            Assert.IsAssignableFrom <User>(result);
            Assert.AreEqual("sam", result.FirstName);
        }