Test Driven Development

Test-driven development (TDD) is a software development process that relies on the repetition of a very short development cycle viz,

1. Requirements are turned into very specific test cases
2. Test the code using a testing framewrok.
3. Then the code is improved so that the tests pass.
4. Repeat 1 - 3, till the expected Behaviour of the product is achieved.

Library Management Application.

This application is an implementation of a library management application, using the Test Driven Development Approach.

Expected Behaviour of the Library Management Application.

The expected behaviour of the application, is described by the various user stories that are outlined as below:

1. User can view books in library Scenario​: As a User I want to see the books present in the library So that I can chose which book to borrow Given​, there are no books in the library When​, I view the books in the library Then​, I see an empty library Given​, there are books in the library When​, I view the books in the library Then​, I see the list of books in the library

2. User can borrow a book from the library Given​, there are books in the library When​, I choose a book to add to my borrowed list Then​, the book is added to my borrowed list And​, the book is removed from the library Note: Each User has a borrowing limit of 2 books at any point of time

3. User can borrow a copy of a book from the library Given​, there are more than one copy of a book in the library When​, I choose a book to add to my borrowed list Then​, one copy of the book is added to my borrowed list And​, the library has at least one copy of the book left Given​, there is only one copy of a book in the library When​, I choose a book to add to my borrowed list Then​, one copy of the book is added to my borrowed list And​, the book is removed from the library Note: Only 1 copy of a book can be borrowed by a User at any point of time

4. User can return books to the library Given​, I have 2 books in my borrowed list When​, I return one book to the library Then​, the book is removed from my borrowed list And​, the library reflects the updated stock of the book Given​, I have 2 books in my borrowed list When​, I return both books to the library Then​, my borrowed list is empty And​, the library reflects the updated stock of the books

Technical Details of the Application.

The application is built using the following technologies.

1. Spring Boot - The Self hosting application container.
2. a.Spring Web, Spring Data JPA.
3. H2 - In Memory Database (currently Data is not persisted over restart).
4. MockMVC - Testing framework for testing the REST APIs.

Details of the API.

1. GET /books - Lists all the unique books in the Library.
2. POST /books - Create a new book entry or add one more copy to Library Catalog.
3. GET /users - Lists all the users in the Library System.
4. POST /users - Create a new user / return user information if user already exist.
5. GET /catalog/books - List all AVAILABLE books in the Catalog.
6. a GET /catalog/books?bookId - List all AVAILABLE books in the Catalog with the given Book Id.
7. GET /catalog/user/{userId} - List all books BORROWED by the user.
8. POST /catalog/user/{userId} - Perform the user action that is BORROW or RETURN for the given userId.

---