diff --git a/src/test/java/fr/iut_fbleau/but3/dev62/mylibrary/book/usecase/BookUseCaseTest.java b/src/test/java/fr/iut_fbleau/but3/dev62/mylibrary/book/usecase/BookUseCaseTest.java
new file mode 100644
index 0000000..3124c88
--- /dev/null
+++ b/src/test/java/fr/iut_fbleau/but3/dev62/mylibrary/book/usecase/BookUseCaseTest.java
@@ -0,0 +1,148 @@
+package fr.iut_fbleau.but3.dev62.mylibrary.book.usecase;
+
+import fr.iut_fbleau.but3.dev62.mylibrary.customer.CustomerInfo;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Nested;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.InjectMocks;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
+
+import java.util.Optional;
+
+import static org.junit.jupiter.api.Assertions.*;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.*;
+
+
+@ExtendWith(MockitoExtension.class)
+public class BookUseCaseTest {
+
+    @Mock
+    private BookRepository customerRepository;
+
+    @InjectMocks
+    private BookUseCase bookUseCase;
+
+    private String bookISBN;
+    private Book testBook;
+    private BookInfo validBookInfo;
+
+
+    @BeforeEach
+    void setUp() {
+
+        testBook = Book.builder()
+                .isbn(bookISBN)
+                .title("LivreRandom")
+                .author("John Doe")
+                .publisher("RandomPublisher")
+                .publicationDate(date)
+                .price(12.5)
+                .initialStock(50)
+                .categories(cat)
+                .description("Je suis un livre qui est composé de mots.")
+                .language("Francais")
+                .build();
+
+        validBookInfo = new CustomerInfo("LivreRandom", "John Doe", "RandomPublisher", date, 12.5, 50, cat, "Je suis un livre qui est composé de mots.", "Francais");
+    }
+
+
+
+    @Nested
+    @DisplayName("Register Book Tests")
+    public class RegisterBookTests {
+
+        @Test
+        @DisplayName("Should register customer when valid data is provided")
+        void testRegisterBookWithValidData() throws NotValidBookException {
+            when(BookRepository.save(any(Book.class))).thenReturn(testBook);
+
+            String registeredISBN = BookUseCase.registerBook(validBookInfo);
+
+            assertNotNull(registeredISBN);
+            assertEquals(bookISBN, registeredISBN);
+            verify(bookRepository, times(1)).save(any(Book.class));
+        }
+
+        @Test
+        @DisplayName("Should throw exception when customer data is not valid")
+        void testRegisterBookWithInvalidData() {
+            BookInfo invalidBookInfo = new BookInfo("", "", "");
+
+            assertThrows(NotValidBookException.class,
+                    () -> bookUseCase.registerBook(invalidBookInfo));
+
+            verify(bookRepository, never()).save(any(Book.class));
+        }
+
+
+
+
+    }
+
+
+    @Nested
+    @DisplayName("Find customer tests")
+    class FindBookTests {
+
+        @Test
+        @DisplayName("Should return book when ISBN exists")
+        void testFindBookByISBN() {
+            when(BookRepository.findBookByISBN("1234567890123")).thenReturn(Optional.of(testISBN));
+
+            Optional<BookDTO> foundBook = bookUseCase.findBookByISBN("1234567890123");
+
+            assertTrue(foundBook.isPresent());
+            assertEquals(testBook.getISBN(), foundBook.get().getISBN());
+            assertEquals(testBook.getName(), foundBook.get().getName());
+            verify(bookRepository, times(1)).findBookByISBN("1234567890123");
+        }
+
+        @Test
+        @DisplayName("Should return empty Optional when ISBN doesn't exist")
+        void testFindBookByISBNNotFound() {
+            when(bookRepository.findByISBN("9999999999999")).thenReturn(Optional.empty());
+
+            Optional<BookDTO> foundBook = bookUseCase.findBookByISBN("9999999999999");
+
+            assertTrue(foundBook.isEmpty());
+            verify(bookRepository, times(1)).findByISBN("9999999999999");
+        }
+
+    }
+
+    @Nested
+    @DisplayName("Delete book tests")
+    class DeleteBookTests {
+
+        @Test
+        @DisplayName("Should delete book when ISBN exists")
+        void testDeleteBook() throws BookNotFoundException {
+            when(bookRepository.findByISBN(bookISBN)).thenReturn(Optional.of(testBook));
+            doNothing().when(bookRepository).delete(testBook);
+
+            bookUseCase.deleteBook(bookId);
+
+            verify(bookRepository, times(1)).findByISBN(bookId);
+            verify(bookRepository, times(1)).delete(testBook);
+        }
+
+        @Test
+        @DisplayName("Should throw exception when book ISBN doesn't exist")
+        void testDeleteBookNotFound() {
+            ISBN nonExistentId = ISBN.randomISBN();
+            when(bookRepository.findByISBN(nonExistentISBN)).thenReturn(Optional.empty());
+
+            assertThrows(BookNotFoundException.class,
+                    () -> bookUseCase.deleteBook(nonExistentISBN));
+
+            verify(bookRepository, times(1)).findByISBN(nonExistentISBN);
+            verify(bookRepository, never()).delete(any(Book.class));
+        }
+    }
+
+}