sinking stdout in rspec

gistfile1.rb

class Foo
  def run
    puts "usage: foo"
    0
  end
end

RSpec.configure do |config|
  config.before(:all) do
    @null_out = File.open('/dev/null', 'w')
    @orig_out = $stdout
  end
  config.before(:each) do
    $stdout = @null_out
  end
  config.after(:each) do
    $stdout = @orig_out
  end
end


describe Foo do
  it { subject.run.should eq(0) }
end