Add unit and integration tests for core healthcare services

[kmuwanga83]

📌 Problem

The project lacks sufficient automated tests, increasing the risk of bugs.

🎯 Objective

Improve reliability by adding test coverage.

✅ Tasks

• Write unit tests for:
  • services
  • business logic
• Write integration tests for API endpoints
• Use JUnit and Mockito (or relevant frameworks)

🧪 Acceptance Criteria

• Tests run successfully
• Core features are covered
• Test instructions are documented