Book Spec

book.rb

STATES = %w(reading pending completed wishlist)

STATES.each do |state|
  define_method "#{state}?" do
    self.state == state
  end
end

book_factory.rb

Factory.define :book do |book|
  book.name                 "The Pragmatic Programmer"
  book.url                  "http://www.pragprog.com"
  book.description          "Lorem Ipsum"
  book.state                "completed"
  book.author               "Someone Famous"
  book.rating               5
end

book_spec.rb

#wrong version
it 'should have a boolean method for it\'s state' do
  subject { Factory :book }
  subject.should be_completed
  subject.should_not be_pending
end

#corrected version
it 'should have the right boolean method' do   
  @book = Factory(:book, :state => 'pending')
  @book.should be_pending
  @book.should_not be_reading
  @book.should_not be_wishlist
  @book.should_not be_completed
end