quiz.rb

# COMMUNITY CHALLENGE
#  
#  A little modification to  @intinig solution ( to test the order as well )
#  May not be the best way to solve the problem.
#
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 "test/unit"
require "rubygems"
require "mocha"
class QuizTest < Test::Unit::TestCase
  class SimpleIO
    attr_reader :buffer
    def initialize
      @buffer = "" 
    end
    
    def puts(s)
      @buffer << s
    end
 
    def gets
      @buffer << "13"
      "13"
    end
  end
  
  def setup
    @io = SimpleIO.new
    @quiz = Quiz.new(@io, @io)
  end
  
  def test_correct
    @quiz.expects(:rand).times(2).returns(7, 6)
    @quiz.problem
    assert_equal "What is 7 + 6?13Correct!", @io.buffer
  end
  
  def test_incorrect
    @quiz.expects(:rand).times(2).returns(5, 9)
    @quiz.problem
    assert_equal "What is 5 + 9?13Incorrect!", @io.buffer
  end
end