@Test
  public void print_itself() throws Exception {
    Book book = aCookingBook().costing(5.0d).build();

    assertThat(book.toString(), is("Book{name='book name', type='COOKING', price=5.0}"));
  }
  @Test
  public void be_named() throws Exception {
    Book book = aCookingBook().build();

    assertThat(book.name(), is("book name"));
  }