Online Learning Platform – Course Enrollment System

Core Requirements

• View all available courses and their enrollment fees.
• Add courses to an enrollment session:
  • If enrollment_id exists, use it.
  • Otherwise, create a new enrollment session for that enrollment_id.
• Scholarship vouchers:
  • Percentage-based scholarships must have a maximum discount cap.
  • Can be applied to an enrollment session.
  • Must be validated for:
    • Expiry date
    • Minimum total enrollment fee eligibility.
• System calculates final payable amount after scholarship application.
• Enrollment can be completed with the discounted amount.
• Course seat capacity must be maintained and updated upon successful enrollment.

Bonus Features

• View student enrollment history (requires a Student entity).
• Handle concurrent scholarship usage:
  • Limited-quantity scholarships.
  • Prevent race conditions when multiple students attempt to use the same limited scholarship.

Expected Deliverables

• Working implementation with proper class structure.
• Basic test cases covering main scenarios.
• Proper error handling.
• Clean and maintainable code.
• Use in-memory data structures instead of an actual database.
• Follow object-oriented design principles.
• Handle edge cases.