Add fb2 parser

src/infrastructure/repository/inmem/books.rs

@@ -160,10 +160,12 @@ impl Repository<book::Book, BookFilter> for BookRepository {
 
     fn filter(&self, f: BookFilter) -> Box<dyn Iterator<Item = book::Book>> {
         let mut author_ids: Vec<String> = vec![];
+        let mut use_author = false;
 
         if let Some(author) = f.author {
             if let Some(id) = author.id {
                 author_ids.push(id);
+                use_author = true;
             }
 
             if let Some(name) = author.name {
@@ -175,12 +177,13 @@ impl Repository<book::Book, BookFilter> for BookRepository {
                             && author.clone().middle_name.unwrap().contains(&name))
                     {
                         author_ids.push(id.to_string());
+                        use_author = true;
                     }
                 }
             }
         }
 
-        if author_ids.is_empty() {
+        if author_ids.is_empty() && use_author {
             return Box::new(std::iter::empty::<book::Book>())
         }