ruby - proc, block, yield - capture stdin/out

gistfile1.rb

require 'stringio'
require 'pp'



def capture_all(proc)
  begin
    $stdout = StringIO.new
    $stderr = StringIO.new
    proc.call
    yield
    result = {}
    result[:stdout] = $stdout.string
    result[:stderr] = $stderr.string
  ensure
    $stdout = STDOUT
    $stderr = STDERR
  end
  result
end


def capture_output(proc, &block)
  error = nil
  result = capture_all(proc) do
    puts 'haha this comes in the end'
  end
  yield result[:stdout] , result[:stderr] if block_given?
  result
end


def invoke_something()
  output = capture_output( proc { puts 'hello test'; $stderr.puts 'error error error' })  do |out, err|
    puts 'testing ....'

    puts out
    puts err
  end

  return output
end

pp invoke_something