module M
  def self.m
    "me"
  end
end

class Object
  def f
    @f ||= M.m
  end
end

describe Object, "#f" do
  before :each do
    M.stub!(:m).and_return(5)
  end

  it "returns 5" do
    f.should == 5
  end

  it "returns 6" do
    M.should_receive(:m).and_return(6)
    f.should == 6
  end
end