one_way.rb

describe PostsController do
  describe "PUT #update" do
    it "allows an author to edit a post" do
      post = Factory(:post)
      sign_in post.author

      put :update, :id => post.id, :body => "new content"
      response.should be_successful
    end

    it "does not allow a non-author to edit a post" do
      post = Factory(:post)
      sign_in Factory(:user)

      put :update, :id => post.id, :body => "new content"
      response.should be_forbidden
   end
  end
end