✅ Reussite du test de préservation du champ string vide après les conversion

src/test/java/fr/iut_fbleau/but3/dev62/mylibrary/book/converter/BookConverterTest.java

@@ -34,7 +34,7 @@ public class BookConverterTest {
                     .language("Français")
                     .build();
 
-            BookDTO result = BookConverter.ToDomain(bookinfo, bookdetails);
+            Book result = BookConverter.ToDomain(bookinfo, bookdetails);
 
             assertEquals(bookinfo.title(), result.getTitle());
             assertEquals(bookinfo.author(), result.getAuthor());
@@ -83,4 +83,24 @@ public class BookConverterTest {
             assertEquals(book.getLanguage(), result.getLanguage());
         }
     }
+
+    @Test
+    @DisplayName("Should preserve empty string values during conversion")
+    void shouldPreserveEmptyStrings() {
+        LocalDate date = LocalDate.of(2026, 3, 24);
+        BookInfo bookinfo = new BookInfo("La vie de Maxime", "Marvin Aubert", "Kioon", date);
+        ArrayList<String> categories = new ArrayList<>();
+        categories.add("Thriller");
+        categories.add("Biographie");
+        BookDetails bookdetails = BookDetails.builder()
+                .categories(categories)
+                .description("")
+                .language("Français")
+                .build();
+
+        Book book = BookConverter.ToDomain(bookinfo, bookdetails);
+        BookDTO result = BookConverter.ToDTO(book);
+
+        assertEquals("", result.getDescription());
+    }
 }