使用Rspec测试回形针图像样式

Question

I have a Banner, with an attached file, using paperclip. Paperclip will create "derivatives" for an uploaded image, using the "styles" parameter:

class Banner < ActiveRecord::Base
  has_attached_file :image,
                    :styles => {:medium => "300x300>",
                                :thumb  => "100x100>"}
end

I want to test this attached_file generation, preferably without testing the whole roundtrip to a disk and so on. I could create a Banner, attach a file and then look on the filesystem if a certain file with certain dimensions is created, but that goes against my idea of testing a focused part, without testing the entire stack.

How can I test if the attached file :image has certain styles in Paperclip?

Answer 1

All the has_attached_file method does is add the passed definitions to the model. The generation is done by paperclip and shouldn't need to be tested.

Source: https://github.com/thoughtbot/paperclip/blob/master/lib/paperclip.rb#L174

However, you could test that the definitions were created properly using the attachment_definitions method. Something like this:

it "has correct image style geometry" do
   Banner.attachment_definitions[:data][:styles][:medium][:geometry].should == "300x300>"
   Banner.attachment_definitions[:data][:styles][:thumb][:geometry].should == "100x100>"
end