carrierwave be_identical_to helper not working in rspec - ruby

Question

I am having some issues with an rspec test I am trying to run on Carrierwave uploads. Basically, I am trying to test processing to make sure if images are uploaded and processed. I have created a post-processed example file that should be identical to the post-uploaded-and-processed test file. However, I am getting the following warning:
ImageUploader the greyscale version should remove color from the image and make it greyscale
Failure/Error: #uploader.should be_identical_to(#pregreyed_image)
TypeError:
can't convert ImageUploader into String
# ./spec/uploaders/image_uploader_spec.rb:24:in `block (3 levels) in <top (required)>'
Here is my test file:
image_uploader_spec.rb
require File.dirname(__FILE__) + '/../spec_helper'
require 'carrierwave/test/matchers'
describe ImageUploader do
include CarrierWave::Test::Matchers
include ActionDispatch::TestProcess
before do
ImageUploader.enable_processing = true
#uploader_attr = fixture_file_upload('/test_images/testimage.jpg', 'image/jpeg')
#uploader = ImageUploader.new(#uploader_attr)
#uploader.store!
#pregreyed_image = fixture_file_upload('/test_images/testimage_GREY.jpg', 'image/jpeg')
end
after do
#uploader.remove!
ImageUploader.enable_processing = false
end
context 'the greyscale version' do
it "should remove color from the image and make it greyscale" do
#uploader.should be_identical_to(#pregreyed_image)
end
end
end
image_uploader.rb
class ImageUploader < CarrierWave::Uploader::Base
# Include RMagick or MiniMagick support:
include CarrierWave::RMagick
# include CarrierWave::MiniMagick
# Include the Sprockets helpers for Rails 3.1+ asset pipeline compatibility:
include Sprockets::Helpers::RailsHelper
include Sprockets::Helpers::IsolatedHelper
# Choose what kind of storage to use for this uploader:
storage :file
# Override the directory where uploaded files will be stored.
# This is a sensible default for uploaders that are meant to be mounted:
def store_dir
"uploads/#{model.class.to_s.underscore}/#{mounted_as}/#{model.id}"
end
# Process files as they are uploaded:
process :convert_to_grayscale
def convert_to_grayscale
manipulate! do |img|
img.colorspace = Magick::GRAYColorspace
img.quantize(256, Magick::GRAYColorspace)
img = yield(img) if block_given?
img
end
end

Answer 1

Underneath the covers be_identical_to uses FileUtils.identical? on the two arguments. So your expectation:
#uploader.should be_identical_to(#pregreyed_image)
is actually calling:
FileUtils.identcal?(#uploader, #pregreyed_image)
Since in my test environment I'm using a file storage system, I got around this by passing in the #current_path rather than the uploader itself like this:
#uploader.current_path.should be_identical_to(#pregreyed_image)
I actually ended up needing to compare uploaders directly and implemented == on my uploader:
class MyUploader < CarrierWave::Uploader::Base
...
def ==(other)
return true if !present? && !other.present?
FileUtils.identical?(current_path, other.current_path)
end
end