Do you have to stub methods in Rspec Ruby

Question

I had a class called listing and product:

class Listing
  belongs_to :product

  def item
    @item ||= Product.find(product_id)
  end

  def url
   "http://example.com/#{@item.pid}"
  end

end


class Product
  has_one :listing
  attr_accessor :pid #returns an integer
end

in my spec file I create a listing object with factory girl and assign it a product. I tested it in previous specs and whenever I called:

@listing.item.id.should eq(@product.id)

It would pass.

However, I tried to call:

@product = FactoryGirl.create(:product)
@listing = FactoryGirl.create(:listing)

@product.listing = @listing
@listing.url.should eq("...")

And it could not call the url method on the listing class ... How could I get this to pass but still make for a good test?

Answer 1

In your Listing model, the instance variable @item only gets defined if the item method is called, which doesn't happen in your test. As a result, when the url method is called, @item is nil and @item.pid results in an undefined method error as a result of sending pid to nil .

You can, however, change your @item.pid reference in the url method to be simply item.pid and you'll be ok, as this will invoke the item method.

While that explains the error you're getting, I can't really advise you on what a good test is because it's not clear what you are trying to accomplish in your application.

Answer 2

I'm confused why you created the item method when you already have the belongs_to association set up.

class Listing
  belongs_to :product

  def url
   "http://example.com/#{product.pid}"
  end
end

class Product
  has_one :listing
  attr_accessible :pid
end

# test setup
# you can define the association in the factory
FactoryGirl.define do
  factory :listing do
    association :product
  end

  factory :product do
    pid 1234
  end
end

# test
listing = FactoryGirl.create(:listing)
listing.url.should eq "http://example.com/1234"