OneBox Software Engineer Test

Table of Contents

1. Abstract
2. Technologies Used
3. Approach to the Solution
4. Pending Topics
5. Possible Improvements
6. How to Run the Application
7. How to Test the Application

📌Abstract

This project is a solution to the OneBox Software Engineer technical test. It involves simulating the functionality of an e-commerce system. To achieve this we implement a RESTful API using clean architecture principles to manage Product and Cart entities. The API supports CRUD operations for both entities while adhering to industry standards and best practices, such as API-first development, validation, robust error handling and testing.

🔎Technologies Used

• Programming Language: Java 21 🍵
• Framework: Spring Boot 3.4.0 (Spring Web, Spring Data JPA, Hibernate) 🍃
• Database: H2 (In-memory database) 🔋
• Build Tool: Maven 🪶
• API Specification: OpenAPI (openapi-generator-maven-plugin)
• Validation: Hibernate Validator (Jakarta Validation API)
• Testing: JUnit 5, MockMvc 🪲
• Postman: A workspace is created (for demo and manual testing)
• GitHub Workflows: Added an Action to validate Pull Requests
• Docker: optional for an easier deployment 🐋

💡Approach to the Solution

1. API-First Design:

   • Defined endpoints and data models using OpenAPI specifications.
   • Autogenerated DTOs and interfaces using openapi-generator-maven-plugin.

2. Hexagonal Architecture:

   • Divided the project into application, domain, and infrastructure layers for better maintainability and separation of concerns.
   • Used ports and adapters to decouple business logic from infrastructure.
   • Applied Vertical Slice to minimize coupling between Products and Carts.

3. Entity Relationships:

   • Implemented a Product entity, representing individual items in the catalog.
   • Designed a Cart entity with a ManyToMany relationship with Product, allowing multiple products to belong to multiple carts.

4. Validation and Error Handling:

   • Applied constraints at the OpenAPI Specification level for data validation.
   • Used a GlobalExceptionHandler for consistent error responses.

5. Testing:

   • Developed integration tests for the endpoints using MockMvc.
   • Verified data persistence with H2 and tested invalid scenarios.

6. Incremental Development:

   • Followed an iterative approach by first implementing Api, then Product functionality and last extending it to Cart.

⏳Pending Topics

1. Improve Test Coverage:

   • Expand unit tests to cover edge cases more comprehensively.
   • Improve integration tests bad path coverage.
   • Add unit tests to mappers.

2. Security:

   • Authentication and authorization mechanisms (e.g., JWT) are not implemented.
   • To achieve this, e-commerce.yaml should be updated including a SecuritySchema.

3. Code Refactor:

   • Extract mappers into a new class.

4. Caching:

   • Introduce in-memory caching (e.g., Caffeine) for frequently accessed data like product details.

5. API Documentation UI:

   • UI integration for interactive API documentation (e.g.: Swagger UI, Stoplight, Redocly).

6. OpenAPI Refactor:

   • Refactor e-commerce.yaml extracting and reusing schemas, responses, requests and errors.

✏️Possible Improvements

1. Testing Enhancements:

   • Include contract tests to validate API compatibility with consumers.
   • Include a Quality Assurance folder to test in depth the use cases.

2. Monitoring:

   • Integrate tools like Prometheus and Grafana for performance monitoring and trace logs.

3. API Versioning:

   • Introduce versioning to maintain backward compatibility.

4. API Decouple:

   • Extract OpenApi generation and data into a spec repository.

5. Data Persistence:

   • Transition from H2 to a production-grade database (e.g.: PostgreSQL or MySQL).

6. CI/CD:

   • Add environments and GitHub Actions to improve the CI/CD

🚀How to Run the Application

1. Requirements:
   • Docker
2. Clone the Repository:

   git clone https://github.com/FrancescFe/oneboxchallenge.git
   cd oneboxchallenge
   

3. Build the Project and Run the Application:

   docker compose up -d
   

4. Access the API:
   • The Application runs at http://localhost:8080
   • Postman workspace created for testing/demo purpose

🧪How to Test the Application

• This Postman workspace can be used:

https://www.postman.com/material-operator-40700101/workspace/onebox-challenge

Although in the Integration Tests data is inserted into the in-memory database using a schema.sql and data.sql, outside the context of the tests, no data insertion has been automated. It must be done manually.