The Unit Test of Silverlight Applications with Asynchronous Service Callbacks

using System;
using System.Collections.Generic;
using System.Runtime.Serialization;
using System.ServiceModel;
using System.Text;

namespace SilverlightHostWebApplication
{
    [DataContract]
    public class Student
    {
        [DataMember(Order = 0)]
        public string ID { get; set; }
        [DataMember(Order = 1)]
        public string Name { get; set; }
        [DataMember(Order = 2)]
        public DateTime EnrollmentDate { get; set; }
        [DataMember(Order = 3)]
        public int Score { get; set; }
        [DataMember(Order = 4)]
        public string Gender { get; set; }
    }

    [ServiceContract]
    public class StudentService
    {
        [OperationContract]
        public List<Student> GenerateStudents(int NoOfStudents)
        {
            // This is the correct method.
            // It returns exactly the same number of students
            // as requested.
            return CreateStudentsList(NoOfStudents);
        }

        [OperationContract]
        public List<Student> GenerateStudentsWithError(int NoOfStudents)
        {
            // This method has an artificial error.
            // It is used to generate a failure in the unit test.
            // The number of students generated is (NoOfStudents - 1)
            return CreateStudentsList(NoOfStudents - 1);
        }

        private List<Student> CreateStudentsList(int NoOfStudents)
        {
            List<Student> students = new List<Student>();

            Random rd = new Random();
            for (int i = 1; i <= NoOfStudents; i++)
            {
                int score = Convert.ToInt16(60 + rd.NextDouble() * 40);
                students.Add(new Student()
                {
                    ID = "ID No." + i.ToString(),
                    Name = "Student Name " + i.ToString(),
                    EnrollmentDate = DateTime.Now,
                    Score = score,
                    Gender = (score >= 80) ? "Famle" : "Male"
                });
            }

            return students;
        }
    }
}