TDD Banking Kata + SOLID + Strategy & Factory Patterns

Description of the Kata: https://kata-log.rocks/banking-kata

Completed Work

• Basic account operations: deposit, withdrawal, and account statement generation.
• TDD (Test-Driven Development).
• Basic Error Handling. In this exercise, I also wanted to explore SOLID principles and the Strategy Design Pattern.
  • SOLID Principles.
  • Design Patterns added:
    • Factory Pattern.
    • Strategy Pattern: Applied for handling different types of fees.

In a Real-World Scenario

The correct level of abstraction needs to be thought through well. Here are other points not covered in this Kata:

• Mocking or Fakes (for Unit Tests)
• Tasks / Asynchronous operations
• Implementing persistence
• Creating RESTful API endpoints and Services
• Authentication & Authorization
• Event-Driven Architecture (integration with other services)
• Dockerization & Microservices (depends on the context)
• CI/CD Pipeline
• Performance Optimization
• Monitoring & Logging
• Documentation

Example of Use of Fees from the Client:

var account = new BankAccount(1000, transactionFactory);
var fixedFeeStrategy = new FixedFeeStrategy(10); // $10 fixed fee
var percentageFeeStrategy = new PercentageFeeStrategy(0.02m); // 2% fee

// Use fixed fee strategy
account.Withdraw(100, fixedFeeStrategy);

// Use percentage fee strategy
account.Withdraw(200, percentageFeeStrategy);