Fixes argument errors

The issue with your code is not related to the test at all.  You have a ruby error.  When I run rspec I get this:

    Failures:
    1) Book#new returns a new book object
    Failure/Error: @book = Book.new "Title", "Author", :category
    ArgumentError:
      wrong number of arguments(3 for 0)
      # ./spec/book_spec.rb:6:in `initialize'
      # ./spec/book_spec.rb:6:in `new'
      # ./spec/book_spec.rb:6:in `block (2 levels) in <top (required)>'

Your book class (../book.rb) has no properties in it.  So when you try to instantiate it like this:
    @book = Book.new "Title", "Author", :category
It fails because the book class does not know what to do with those extra arguments (Title, Author, category).  Removing the arguments fixes the error:
    @book = Book.new

The real fix is to add the properties to the Book class.  Looks like you may have forgotten a step from the tutorial.

Did you get that same error?