quiz.rb

# COMMUNITY CHALLENGE
#
# How would you test this Quiz#problem method? No mocks/stubs allowed.
class Quiz
  def initialize(input = STDIN, output = STDOUT)
    @input = input
    @output = output
  end
  
  def problem
    first = rand(10)
    second = rand(10)
    @output.puts "What is #{first} + #{second}?"
    answer = @input.gets
    if answer.to_i == first + second
      @output.puts "Correct!"
    else
      @output.puts "Incorrect!"
    end
  end
end

require "rubygems"
require 'spec/autorun'

describe "Quiz" do
  before do
    @io = mock("IO")
    @quiz = Quiz.new(@io, @io)
  end
  
  it "should work with a correct answer" do
    @quiz.should_receive(:rand).ordered.twice.and_return(7, 6)
    @io.should_receive(:puts).ordered.with("What is 7 + 6?")
    @io.should_receive(:gets).ordered.and_return("13")
    @io.should_receive(:puts).ordered.with("Correct!")
    @quiz.problem
  end

  it "should work with an incorrect answer" do
    @quiz.should_receive(:rand).ordered.twice.and_return(5, 9)
    @io.should_receive(:puts).ordered.with("What is 5 + 9?")
    @io.should_receive(:gets).ordered.and_return("foobar")
    @io.should_receive(:puts).ordered.with("Incorrect!")
    @quiz.problem
  end
end