How to stub paperclip file paths in Capybara/Rspec - ruby-on-rails

Question

For some application I am using Paperclip for file upload (actually the dm-paperclip flavour), and Factory Girl, Rspec, Capybara for testing.
I have a very simple Factory for the "Picture" model, where I am stubbing my file properties as suggested in this post:
FactoryGirl.define do
factory :picture do
title "My Picasso"
description "It's like looking in a mirror."
picture_file_file_name { 'spec/resources/img_1.jpg' }
picture_file_content_type { 'image/jpg' }
picture_file_file_size { 1024 }
end
end
In diverse feature tests with Capybara, I visit pages in which the templates feature thumbnails of the Picture instances:
feature "List of Pictures", :js => true do
scenario "displays appropriately the index page of the pictures with pagination" do
FactoryGirl.create_list(:picture, 21)
visit '/pictures'
# And more testing...
end
end
An example of partial used in one of the templates:
= content_tag_for(:li, picture, :class => 'listed_picture') do
= link_to picture_path(picture) do
- if picture.picture_file?
= image_tag picture.picture_file.url(:thumb)
The problem I have now, is whenever I run the specs, the test fails because there is no matching route for the thumbnail url:
No route matches [GET] "/system/picture_files/1/thumb/img_1.jpg"
Is there any way to stub Paperclip's helper methods to make the test pass?
Thanks in advance for any help!

Answer 1

I just went through this process. Here's how I solved the issue.
First, I created a single method on the object to reference the image URL, both to abide by the law of Demeter and to make for an easier test. For you, that might look like:
#picture.rb
class Picture
...
def picture_file_url(size = nil)
picture_file.url(size)
end
...
end
Now we're ready to stub the Paperclip attachment URL in the spec:
describe "List of Pictures", :js => true do
it "displays appropriately the index page of the pictures with pagination" do
let(:picture) { create(:picture) }
allow(Picture).to receive(:picture_file_url) { "url" }
visit '/pictures'
# And more testing...
end
end
Hope this helps you or someone.