Rails fixture's monkey patch. It allows to preload fixtures before the tests and speed up the process

fixture_loader.rb

# frozen_string_literal: true

module Tests::FixtureLoader
  extend ActiveSupport::Concern

  included do
    # Копипаста https://github.com/rails/rails/blob/844106efa9bc110260724d0fe503c321e7eb5b16/activerecord/lib/active_record/test_fixtures.rb#L210
    # Можно улучшить
    fixture_path = ActiveSupport::TestCase.fixture_path
    fixture_set_names = Dir[::File.join(fixture_path, '{**,*}/*.{yml}')].uniq
    fixture_set_names.map! { |f| f[fixture_path.to_s.size..-5].delete_prefix('/') }

    fixture_set_names.each do |name|
      # TODO оригинальные методы принимают на вход любое количество лейблов
      define_method name.tr('/', '_') do |label|
        id = ActiveRecord::FixtureSet.identify(label)
        obj = name.singularize.classify.constantize.find_by(id: id)
        raise "#{name}(:#{label}) has not found an object. Did you preload fixtures?" unless obj

        obj
      end
    end
  end
end