Testing modules

gistfile1.rb

module Foo
  def bar
    "A cow"
  end
end

describe Foo
  let :subject_class { Class.new }
  let :subject { subject_class.new }

  before :each do
    subject_class.class_eval { include Foo }
  end

  it "returns a cow" do
    subject.bar.should eq "A cow"
  end
end

You can also use:

  before :each do
    subject.extend(Foo)
  end