/// <summary>
/// Given a Course.Id and a student's username, enroll the student in that course. If
/// a student record doesn't exist (e.g. the student was never enrolled in a course),
/// a record is created internally and the course is added to the StudentRecord.StudentCourseEnrollments.
/// If the student already has a record, we udpate the student's enrollments with the new course
/// enrollment.
/// </summary>
/// <param name="username">The username is how we uniquely track/identify a StudentRecord</param>
/// <param name="courseId">The Course.Id (unique id of the course)</param>
/// <exception cref="System.InvalidOperationException">
/// <para>
/// 1) If the given course (by Course.Id) does not exist in the system
/// 2) If the student is already enrolled in that course
/// </para>
/// </exception>
/// <returns>A copy of the persisted/updated StudentRecord</returns>
public StudentRecord AddEnrollment(string username, string courseId)
{
IRepository<Course, string> coursesRepo = new BizCollegeRepository<Course, string>();
var course = coursesRepo.Get(courseId);
if (course == null)
throw new InvalidOperationException("That course does not exist in the system");
// Try and retrive the student's record (by username). If they don't
// have an existing record, create a record for them
var student = m_enrollmentsRepo.Get(username);
if (student == null)
{
student = new StudentRecord() { Username = username, StudentCourseEnrollments = new List<Enrollment>() };
}
// Throw an error if the student is already enrolled in this course
foreach (var currentEnrollment in student.StudentCourseEnrollments)
{
if (currentEnrollment.CourseId == courseId)
{
throw new InvalidOperationException("The student is already enrolled in course: " + courseId);
}
}
// Add the new enrollment and save it the updated student record
student.StudentCourseEnrollments.Add(new Enrollment()
{
CourseId = courseId,
DateStarted = DateTime.Now,
DateCompleted = SqlServerHelper.GetSqlServerMinimumDateTimeValue()
});
return m_enrollmentsRepo.AddOrUpdate(student);
}
public void CanGetStudentEnrollment()
{
// dummy username and course id
string username = "******";
string courseId = Guid.NewGuid().ToString();
// Add the dummy student enrollment via the internal repository interfaces
var dummyEnrollment = new StudentRecord(){ Username = username};
dummyEnrollment.StudentCourseEnrollments = new List<Enrollment>();
dummyEnrollment.StudentCourseEnrollments.Add(
new Enrollment()
{
CourseId = courseId,
DateStarted = DateTime.Now,
DateCompleted = SqlServerHelper.GetSqlServerMinimumDateTimeValue()
}
);
var enrollmentsRepo = new BizCollegeRepository<StudentRecord, string>();
dummyEnrollment = enrollmentsRepo.AddOrUpdate(dummyEnrollment);
// Get the student record via the enrollments model interface that the web
// application will use to retrieve student enrollment records by username
IStudentEnrollmentsModel enrollmentsModel = new StudentEnrollmentsModel();
var fromDb = enrollmentsModel.GetStudentRecord(username);
Assert.NotNull(fromDb);
Assert.AreEqual(fromDb.Username, dummyEnrollment.Username);
Assert.NotNull(fromDb.StudentCourseEnrollments);
Assert.AreEqual(fromDb.StudentCourseEnrollments.Count, dummyEnrollment.StudentCourseEnrollments.Count);
Assert.AreEqual(fromDb.StudentCourseEnrollments[0].Id, dummyEnrollment.StudentCourseEnrollments[0].Id);
Assert.AreEqual(fromDb.StudentCourseEnrollments[0].CourseId, dummyEnrollment.StudentCourseEnrollments[0].CourseId);
Assert.AreEqual(fromDb.StudentCourseEnrollments[0].DateCompleted, dummyEnrollment.StudentCourseEnrollments[0].DateCompleted);
// Clean up Db
enrollmentsRepo.Remove(username);
}
public void CanRemoveStudentEnrollment()
{
// dummy username and course id
string username = "******";
string courseId = Guid.NewGuid().ToString();
// Add the dummy student enrollment via the internal repository interfaces
var dummyEnrollment = new StudentRecord() { Username = username };
dummyEnrollment.StudentCourseEnrollments = new List<Enrollment>();
dummyEnrollment.StudentCourseEnrollments.Add(
new Enrollment()
{
CourseId = courseId,
DateStarted = DateTime.Now,
DateCompleted = SqlServerHelper.GetSqlServerMinimumDateTimeValue()
}
);
var enrollmentsRepo = new BizCollegeRepository<StudentRecord, string>();
dummyEnrollment = enrollmentsRepo.AddOrUpdate(dummyEnrollment);
// Remove the enrollment via the enrollmnent model interface that the webapp
// will use to remove a student's enrollment from their record
IStudentEnrollmentsModel enrollmentsModel = new StudentEnrollmentsModel();
enrollmentsModel.RemoveEnrollment(username, courseId);
// retrieve the enrollment record from the Db and ensure the student has
// no enrollments in his/her student record
var fromDb = enrollmentsRepo.Get(username);
Assert.NotNull(fromDb);
Assert.AreEqual(fromDb.Username, username);
Assert.AreEqual(fromDb.StudentCourseEnrollments.Count, 0);
// clean up Db
enrollmentsRepo.Remove(fromDb.Username);
}
public void CanUpdateExistingStudentEnrollmentsCollection()
{
// dummy username and dummy courses
string username = "******";
var dummyCourse1 = DummyDataGenerator.CreateDummyCourse();
var dummyCourse2 = DummyDataGenerator.CreateDummyCourse();
// Add the dummy courses to the database via the internal course repository interface
IRepository<Course, string> coursesRepo = new BizCollegeRepository<Course, string>();
dummyCourse1.Id = coursesRepo.AddOrUpdate(dummyCourse1).Id;
dummyCourse2.Id = coursesRepo.AddOrUpdate(dummyCourse2).Id;
// Add the dummy student enrollment via the internal enrollments repository interfaces
var dummyEnrollment = new StudentRecord() { Username = username };
dummyEnrollment.StudentCourseEnrollments = new List<Enrollment>();
dummyEnrollment.StudentCourseEnrollments.Add(
new Enrollment()
{
CourseId = dummyCourse1.Id,
DateStarted = DateTime.Now,
DateCompleted = SqlServerHelper.GetSqlServerMinimumDateTimeValue()
}
);
var enrollmentsRepo = new BizCollegeRepository<StudentRecord, string>();
dummyEnrollment = enrollmentsRepo.AddOrUpdate(dummyEnrollment);
// To update the student enrollment, we'll add another enrollment to their
// current enrollment record (so we should have two enrollments after the update)
IStudentEnrollmentsModel model = new StudentEnrollmentsModel();
var updatedRecord = model.AddEnrollment(username, dummyCourse2.Id);
Assert.NotNull(updatedRecord);
Assert.IsNotNullOrEmpty(updatedRecord.Username);
Assert.AreEqual(updatedRecord.Username, username);
Assert.NotNull(updatedRecord);
Assert.IsNotNullOrEmpty(updatedRecord.Username);
Assert.NotNull(updatedRecord.StudentCourseEnrollments);
Assert.AreEqual(updatedRecord.StudentCourseEnrollments.Count, 2);
var updatedEnrollments = new List<Enrollment>(updatedRecord.StudentCourseEnrollments);
Assert.AreEqual(updatedEnrollments[0].CourseId, dummyCourse1.Id);
Assert.AreEqual(updatedEnrollments[1].CourseId, dummyCourse2.Id);
// Clean up Db
enrollmentsRepo.Remove(username);
coursesRepo.Remove(dummyCourse1.Id);
coursesRepo.Remove(dummyCourse2.Id);
}