public void testAddBooks() {
   try {
     File inputFile = new File("testAddBooks.txt");
     FileReader fileReader = new FileReader(inputFile);
     BufferedReader bufferedReader = new BufferedReader(fileReader);
     newCatalogue.addBooks(bufferedReader);
     newCatalogue.viewCatalogueByTitle();
     System.out.println();
     newCatalogue.viewCatalogueByAuthor();
     System.out.println();
     Iterator itr = newCatalogue.iterator();
     while (itr.hasNext()) {
       Book tmpBook = (Book) itr.next();
       System.out.println(tmpBook.getQuantity());
     }
   } catch (IOException e) {
     System.out.println(e.getMessage());
   }
 }
 public void testViewCatalogueByAuthor() {
   newCatalogue.viewCatalogueByAuthor();
   System.out.println();
 }