Rails - Singleton class troubles with rspec feature - ruby-on-rails

Question

I have a problem testing a functionality that depends of a Singleton class. That class (ERPDao) is a suite with diferent methods that helps application to connect with external ERP vía REST services using Faraday gem. URLMaker is a helper class for build requests strings. When i try to run a feature spec that depends of one of this methods i have the following message in rspec:
Failure/Error: result = ERPDao.instance.get_credit_info(erp_id)
NoMethodError:
undefined method `instance' for ERPDao:Class
Did you mean? instance_of?
Did you mean? instance_of?
My class ERPDao
class ERPDao
def initialize
#end_points = EndPoint.first
#connection = Faraday.new(:url => #end_points.url_base, request: {
open_timeout: 10, # opening a connection
timeout: 10 # waiting for response
})
end
##instance = ERPDao.new
def self.instance
return ##instance
end
def get_credit_info(erp_id)
begin
return #connection.get URLMaker.instance.get_uri('credit_info', erp_id)
rescue Faraday::Error::ConnectionFailed => e
puts "Connection failed: #{e}"
return 0, false, 0
end
end
...
end
My rails_helper.rb
require 'spec_helper'
ENV['RAILS_ENV'] ||= 'test'
require File.expand_path('../../config/environment', __FILE__)
abort("The Rails environment is running in production mode!") if Rails.env.production?
require 'rspec/rails'
require 'support/factory_bot'
require 'support/wait_for_ajax'
ActiveRecord::Migration.maintain_test_schema!
RSpec.configure do |config|
config.fixture_path = "#{::Rails.root}/spec/fixtures"
config.use_transactional_fixtures = false
config.before :suite do
DatabaseCleaner.strategy = :truncation
end
config.before :each do
DatabaseCleaner.clean
end
config.infer_spec_type_from_file_location!
config.filter_rails_from_backtrace!
config.include Warden::Test::Helpers
config.include Devise::TestHelpers, type: :controller
Shoulda::Matchers.configure do |config|
config.integrate do |with|
with.test_framework :rspec
with.library :rails
end
end
Capybara.javascript_driver = :webkit
Capybara::Webkit.configure do |config|
config.debug = false
config.allow_unknown_urls
config.skip_image_loading
config.timeout = 15
config.raise_javascript_errors = false
end
end
My version of rails is 4.2.6, ruby 2.3.1, factory_bot 4.8.2 and rspec-rails 3.7.
Someone knows about this error?
Thanks!

Answer 1

ERPDao is [also] being defined somewhere else. Maybe someone decided to add a method to it by re-opening the class like
class ERPDao
def some_new_method
...
end
end
Don't do that. Use modules and prepend instead.
module HasMyNewMethod
def some_new_method
...
end
end
ERPDau.prepend HasMyNewMethod
Otherwise you end up accidentally referencing the re-opening of the class and that becomes the definition - so the autoloader doesn't load it since it's already defined.
Search your codebase for 'class ERPDao'. Modify the ones that are not the initial declaration.