Unit testing Rails applications' controller's helper Module - How?

Question

In my rails application there exists a controller helper which is a Module (not a Class) with lot of helper methods defined in it. I wish to write unit test cases for this before I do code refactoring of this module so as to ensure that my understanding of the current system is right and that I have not broken any functionality inadvertantly. We are using RSpec and I would wish to know how would one go about writing unit test cases for the methods of this helper Module?

Answer 1

Assume you have app/helpers/address_helper.rb:

module AddressHelper
  def full_address(address)
    "#{address.street} #{address.house_number}/#{address.local_number}"
  end
end

You can write spec under spec/helpers/address_helper_spec.rb:

require 'spec/spec_helper' #or something similar, in order to load spec helper

describe AddressHelper do
  describe "#full_address" do
    it "displays the street, local and house number" do
      address = stub('Address', :street => 'Mountain View', :house_number => '7', :local_number => '44')
      helper.full_address(address).should eql('Mountain View 7/44')
    end 
  end
end

Key here is helper method, which gives you access to helper methods, in this example it is:

helper.full_address(address)