https://rainveiltech.com/posts/rails-writing-engine-tests-that-depend-on-main-application-models
https://netguru.co/blog/rails-api-as-an-engine another approach??
| # Configure Rails Environment | |
| ENV["RAILS_ENV"] = "test" | |
| require File.expand_path("../../test/dummy/config/environment.rb", __FILE__) | |
| ActiveRecord::Migrator.migrations_paths = [File.expand_path("../../test/dummy/db/migrate", __FILE__)] |