How can I share the factories that I have in a GEM and use it in other project?

Question

I have a gem that includes some Factories. The gem looks something like:

.
├── Gemfile
├── Gemfile.lock
├── README.md
├── Rakefile
├── db
├── lib
│   ├── mo         


        

Answer 1

An alternative to require-ing each factory file as suggested in the other answer, is to update the FactoryBot.definition_file_paths configuration.

In your gem defining the factories:

Create a file which will resolve the factory path:

# lib/my_gem/test_support.rb

module MyGem
  module TestSupport
    FACTORY_PATH = File.expand_path("../../spec/factories", __dir__)
  end
end

In you app / gem using the factories from the other gem:

# spec/spec_helper.rb or similar

require "my_gem/test_support"

FactoryBot.definition_file_paths = [
  MyGem::TestSupport::FACTORY_PATH,
  # Any other paths you want to add e.g.
  # Rails.root.join("spec", "factories")
]

FactoryBot.find_definitions

The advantage of the definition_file_paths solution is that other functionality like FactoryBot.reload will work as intended.

Answer 2

The problem is that you probably don't expose the spec folder (and herewith the factories) in the load path. Which, in general, is the right thing to do. Check you *.gemspec, you probably have something like:

s.require_paths = ["lib"]

This means only files under the lib directory can be required by other projects using your gem. See http://guides.rubygems.org/specification-reference/#require_paths=

So to solve your problem, you'd need to place a file inside the lib folder which 'knowns' where your factories are and requires those. So in you case, create a file lib/<your gem name>/factories.rb and add:

GEM_ROOT = File.dirname(File.dirname(File.dirname(__FILE__)))

Dir[File.join(GEM_ROOT, 'spec', 'factories', '*.rb')].each { |file| require(file) }

In the other Project load the factories with:

require '<your gem name>/factories'

Works fine for me. The only thing I havn't figured out yet is how to namespace your factories. Not sure if factory girl allows this.