From: "Skye Shaw!@#$" <skye.shaw@...>
Date: 2007-08-08T16:04:57+09:00
Subject: Re: capturing stdout during unit tests

On Aug 7, 8:59 pm, Mark Slater <li...@humanesoftware.com> wrote:
> I've written a script for use with Nagios (a monitoring tool) that
> I'd like to test.

<snip>

> I'm now writing unit tests for my script, and I'd like to check that
> the output written to STDOUT by each service monitor class is
> correct. But I'm new to Ruby and I'm not sure how to do that. In
> other languages, I'd simply redefine STDOUT as a stream that goes to
> a large in-memory buffer,

What language is this in?

> but I haven't seen anything that suggests that is possible in Ruby.
At any rate, Ruby does have similar functionality. An example:

require 'stringio'
class Bs
   attr :output_stream,true

   def do_some_output(data)
    output_stream.puts(data)
   end
end

bs=Bs.new
bs.output_stream=$stdout
bs.do_some_output("this is to stdout")

expect="grrrrrrrr"
result=String.new

bs.output_stream=StringIO.new(result,"w+")
bs.do_some_output("Waka waka waka!")
bs.output_stream.close

puts "result= " + result
puts "expect= " + expect

[sshaw@localhost sshaw]# ruby bs.rb
this is to stdout
result= Waka waka waka!
expect= grrrrrrrr