As an additional note to this, assigning constants in a describe under
1.8 causes namespace pollution.

  require 'rubygems'
  require 'minitest/spec'

  module X
    module Y
    end
  end

  describe "Namespace Pollution" do
    Y = X::Y
  end

  puts Y  # => 'X::Y' on 1.8, error on 1.9