Add deleteBookById() with idempotency; Update tests to use findById()

Author: codesungrape

src/main/java/com/codesungrape/hmcts/bookapi/service/BookService.java

@@ -2,18 +2,21 @@
 
 import com.codesungrape.hmcts.bookapi.dto.BookRequest;
 import com.codesungrape.hmcts.bookapi.entity.Book;
+import com.codesungrape.hmcts.bookapi.exception.ResourceNotFoundException;
 import com.codesungrape.hmcts.bookapi.repository.BookRepository;
 import lombok.RequiredArgsConstructor;
 import org.springframework.stereotype.Service;
 
+import java.util.UUID;
+
 /**
  * Service layer responsible for all business logic related to the Book resource.
  */
 @Service
 @RequiredArgsConstructor // Lombok creates constructor for dependency injection
 public class BookService {
 
-    // Create a field to store the repo
+    // Create a field to store the repo in this scope to be accessed and used/reused by methods below
     private final BookRepository bookRepository;
 
     /**
@@ -54,4 +57,18 @@ public Book createBook(BookRequest request) {
 
         return savedBook;
     }
+
+    // Soft Delete
+    public void deleteBookById(UUID bookId) {
+
+        // find the book only if it's not already soft-deleted
+        Book book = bookRepository.findById(bookId)
+            .orElseThrow(() -> new ResourceNotFoundException("Book not found"));
+
+        // Idempotent way to mark soft-delete and save
+        if (!book.isDeleted()) {
+            book.setDeleted(true);
+            bookRepository.save(book);
+        }
+    }
 }

src/test/java/com/codesungrape/hmcts/bookapi/BookServiceTest.java

@@ -283,7 +283,7 @@ void testDelete_Book_ShouldThrowException_WhenIdNotFound() {
 
         // Arrange: As goal is to test what happens when the resource doesn't exist,
         // we intentionally simulate DB returning NO result
-        when(testBookRepository.findByIdAndDeletedFalse(testId)).thenReturn(Optional.empty());
+        when(testBookRepository.findById(testId)).thenReturn(Optional.empty());
 
         // ACT and ASSERT: throw ResourceNotFoundException when calling the delete method.
         assertThrows(
@@ -303,7 +303,7 @@ void testDeleteBookById_Success() {
         // Arrange:
         persistedBook.setDeleted(false); // ensure starting state
 
-        when(testBookRepository.findByIdAndDeletedFalse(testId))
+        when(testBookRepository.findById(testId))
             .thenReturn(Optional.of(persistedBook));
 
         when(testBookRepository.save(any(Book.class)))
@@ -316,7 +316,7 @@ void testDeleteBookById_Success() {
         assertTrue(persistedBook.isDeleted());
 
         // Assert: repository methods were called correctly
-        verify(testBookRepository, times(1)).findByIdAndDeletedFalse(testId);
+        verify(testBookRepository, times(1)).findById(testId);
         verify(testBookRepository, times(1)).save(persistedBook);
     }
 }