layout

General layout:
root
 lib
  hw1
   part1.rb
 spec
  hw1
   part1_spec.rb
 .rspec
 Guardfile

You will need the following gems
rspec
guard 
guard-rspec

# lib\rspec_helper
APP_ROOT = File.expand_path(File.join(File.dirname(__FILE__), ".."))
(1..1).each do |i|
  $: << File.join(APP_ROOT, "lib/hw#{i}")
end

RSpec.configure do |config|
  # ## Mock Framework
  #
  # If you prefer to use mocha, flexmock or RR, uncomment the appropriate line:
  #
  # config.mock_with :mocha
  # config.mock_with :flexmock
  # config.mock_with :rr
end

# .\Guardfile
# More info at https://github.com/guard/guard#readme

guard 'rspec', :version => 2 do
  watch(%r{^spec/.+_spec\.rb$})
  watch(%r{^lib/(.+)\.rb$})     { |m| "spec/#{m[1]}_spec.rb" }
  watch('spec/spec_helper.rb')  { "spec" }
end

# .\.rspec
--color

now simply type `guard` in your console in the root folder and go solve the problems.