Include module in rspec

Please forgive my gherkin

Given I have a module called Hello
And it has a method called world and a class called World
When I include the module in an RSpec spec
And I call the method world
Then it returns "hello world from method"
But when I create a World class
Then I get NameError: uninitialized constant World

module Hello
  def world
    p "hello world from method"
  end
  class World
     def initialize
       p "hello world from class"
     end
  end
end

describe "hello world" do
  include Hello
  it "call method" do
    world
  end

  it "call class" do
    World.new
  end
end

Forgive my Gherkin, and unless you intended something else (as that's not clear)

When I create a Hello::World class  
Then I get an object of kind Hello::World

it "should not catch fire on instantiation" do
  Hello::World.new.should_not be_nil
end