Question

Here is the code for my specs and class:

describe Game do

  before(:each) do
    @game = Factory.build(:game)
  end

  describe '#no_books?' do
    it 'should return true if books attribute is empty' do
      @game.stub(:books).and_return([])
      @game.no_books?.should be_true
    end

    it 'should return false if books attribute is present' do
      @game.no_books?.should be_false
    end
  end

end


class Game

  attr_reader :books

  def initialize
    @books = parse_books
  end

  def no_books?
    @books.empty?
  end

  protected

  def parse_books
    # return books
  end

end

I then get a friendly spec failure message:

Game#no_books? should return true if books attribute is empty
     Failure/Error: @game.no_books?.should be_true
       expected false to be true

It’s as if that method is getting called before the attribute books get initialized with a value. Can someone explain to me what’s going here?

Answer 1

Your no_books? implementation is using the instance variable directly in its check, bypassing your stub. If you change no_books? to return books.empty?, it will call the stub instead.

If you really, really want to keep using the instance variable, you can set it in @game via instance_variable_set like this:

@game.instance_variable_set("@books", [])