ruby - rspec puts output test -

i'm having trouble understanding how test output puts. need know need in rspec file.

this rspec file:

require 'game_io' require 'board'   describe gameio   before(:each)     @gameio = gameio.new     @board  = board.new   end    context 'welcome_message'     'should display welcome message'       test_in   = stringio.new("some test input\n")       test_out  = stringio.new       test_io   = gameio.new(test_in, test_out)        test_io.welcome_message       test_io.game_output.string.should == "hey, welcome game. ready defeated"     end   end  end 

this file testing against:

class gameio   attr_reader :game_input, :game_output   def initialize(game_input = $stdin, game_output = $stdout)     @stdin  = game_input     @stdout = game_output   end     def welcome_message      output "hey, welcome game. ready defeated"    end     def output(msg)     @stdout.puts msg   end    def input     @stdin.gets   end  end 

note: updated rspec code reflect changes made test file given suggestions found elsewhere. resolve poblem completly used changes suggested chris heald in main file. thank , thank chris.

your initializer should be:

def initialize(game_input = $stdin, game_output = $stdout)   @game_input  = game_input   @game_output = game_output end 

the reason attr_accessor generates methods this:

# attr_accessor :game_output def game_output   @game_output end  def game_output=(output)   @game_output = output end 

(attr_reader generates reader method)

thus, since never assign @game_output, game_output method return nil.