public async Task SignUp()
        {
            ParseUser user = new ParseUser {
                Username = username,
                Password = password,
                Email    = email,
                Mobile   = mobile
            };
            await user.SignUp();

            TestContext.WriteLine(user.Username);
            TestContext.WriteLine(user.Password);

            Assert.NotNull(user.ObjectId);
            TestContext.WriteLine(user.ObjectId);
            Assert.NotNull(user.SessionToken);
            TestContext.WriteLine(user.SessionToken);
            Assert.AreEqual(user.Email, email);
        }