Freezing random generator and capturing output of ruby script without changing original file ['jbrains/trivia', 'golden master']

script-wrapper.rb

require 'stringio'

def capture_stdout_string
  io = StringIO.new

  capture_stdout(io) do
    yield
  end

  io.string
end

def capture_stdout(io)
  original_stdout = $stdout
  $stdout = io
  yield
ensure
  $stdout = original_stdout
end

puts 'Testing namespace protection'
puts
puts "load 'test-load.rb', true"
result = capture_stdout_string do
  load 'test-load.rb', true
  puts @foo
end
puts "@foo = #{result}"

puts "load 'test-load.rb', false"
result = capture_stdout_string do
  load 'test-load.rb', false
  puts @foo
end
puts "@foo = #{result}"

puts
puts 'Testing the freezing of random number generator'
puts
puts 'First Sequence:'

srand(7777)

result = capture_stdout_string do
  load 'script.rb', true 
end
puts "Result: #{result}"

result = capture_stdout_string do
  load 'script.rb'
end
puts "Result: #{result}"

puts
puts 'Second Sequence'

##
# Reset sequence of random numbers
# To match results of first and second runs
#
# Each call to 'rand' would generate new number
# but the sequence is repeatable, see test-srand.rb
srand(7777)

result = capture_stdout_string do
  load 'script.rb'
end
puts "Result: #{result}"

result = capture_stdout_string do
  load 'script.rb'
end
puts "Result: #{result}"

script.rb

#!/usr/bin/env ruby

puts rand

test-load.rb

@foo = 'bar'

test-srand.rb

srand 7777
puts rand
puts rand
puts rand