rspec STDOUT

I happened to write some rspec for one ruby program which was accepting some input text in some form, and then it was expected to print the output to the console, or perhaps I did not want to separate the logic of printing. Anyways, that made me expect rspec should check the console output of my program, and after some googling(thanks to many rubyist) I got to work the following

	require 'spec_helper'
	describe "Transaction" do
	it "should handle dummy numerals" do
	transaction_input(%{
	x1 is I
	x5 is V
	x10 is X
	x50 is L
	x100 is C
	x500 is D
	x1000 is M
	how much is x1000 x100 ?
	how much is x1 x1 ?
	how much is x1 x5 ?
	}
	).should_output(%{
	x1000 x100 is 1100
	x1 x1 is 2
	x1 x5 is 4
	})
	end
	end

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transaction_spec.rb

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Wow, I liked it.

And the spec_helper made it for me

	require "#{File.dirname(__FILE__)}/../lib/transactions.rb"
	include Transactions
	def capture_stdout(&block)
	original_stdout = $stdout
	$stdout = fake = StringIO.new
	begin
	yield
	ensure
	$stdout = original_stdout
	end
	fake.string
	end
	class TransactionInput
	def initialize output
	@output = output
	end
	def should_output output
	@output.split("\n").should == output.split("\n")[1..-2].collect{|line| line.strip}
	end
	end
	def transaction_input input
	TransactionInput.new capture_stdout{ input.split("\n")[1..-2].each{|line| Message.new(line).process} }
	end

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spec_helper.rb

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