Fixed issue where querying empty collection returns an empty book record

internal/adapter/adapter.go

@@ -14,7 +14,10 @@ func CollectionQueryToCollectionDto(collectionsQueryResult []query.CollectionsQu
 	var collection dto.CollectionGet
 	for _, collectionsDb := range collectionsQueryResult {
 		collection.Name = collectionsDb.Name
-		collection.Books = append(collection.Books, collectionDbToBookItem(&collectionsDb))
+		book := collectionDbToBookItem(&collectionsDb)
+		if book != nil {
+			collection.Books = append(collection.Books, *book)
+		}
 		collection.UserID = collectionsDb.UserID
 	}
 	return collection
@@ -32,16 +35,24 @@ func CollectionQueryToCollectionItemDto(collectionsQueryResult []query.Collectio
 			//current collection is the last element
 			i = len(collections) - 1
 		}
-		collections[i].Books = append(collections[i].Books, collectionDbToBookItem(&collectionDb))
+		book := collectionDbToBookItem(&collectionDb)
+		if book != nil {
+			collections[i].Books = append(collections[i].Books, *book)
+		}
 	}
 	return collections
 }
 
-func collectionDbToBookItem(collectionDb *query.CollectionsQueryResult) dto.CollectionBookItemGet {
-	return dto.CollectionBookItemGet{
-		ID:        collectionDb.BookId,
-		Title:     collectionDb.BookTitle,
-		CoverPath: collectionDb.CoverPath,
+func collectionDbToBookItem(collectionDb *query.CollectionsQueryResult) *dto.CollectionBookItemGet {
+	if collectionDb.BookId > 0 {
+		bookItem := dto.CollectionBookItemGet{
+			ID:        collectionDb.BookId,
+			Title:     collectionDb.BookTitle,
+			CoverPath: collectionDb.CoverPath,
+		}
+		return &bookItem
+	} else {
+		return nil
 	}
 }