AssociationTypeMismatch and FactoryGirl

Question

This has been causing some frustration recently...

It seems that using Factories in my cucumber tests, in some situations causes AssociationTypeMismatch errors such as:

MyModel(#65776650) expected, got MyModel(#28190030) (ActiveRecord::AssociationTypeMismatch)

These seem to happen when there is an association reference - as if the Factory created object is different to the real one. See this question for more details: Cucumber duplicate class problem: AssociationTypeMismatch

I have been gradually changing Factory calls to real Model.create or mock_model calls. It would be nice to keep using Factory girl... I wonder if there is something I may have done wrong?

Thank you

Answer 1

I had this happening with me on Rails 3.1.0 rc5, and got it working.

To expand on Jonas' answer.

You should change your Gemfile to be like this:

gem 'factory_girl', '~> 2.0.0', :require => false
gem 'factory_girl_rails', '~> 1.1.0', :require => false

And then if you are using Spork, make your spec/spec_helper.rb file look like this:

Spork.each_run do
 require 'factory_girl'
 require 'factory_girl_rails'
end

Answer 2

It seems to happen if ActiveSupport unloads and reloads a constant that you have a reference to. I've experienced the same with Rspec/Capybara, and what helped was a mixture of different things:

• Make sure you have cached_classes set to false in your test environment (config/environments/test.rb)
• In your gemspec, try replacing require 'factory_girl_rails' with 'factory_girl'

I'm using Spork (a test server), which seems to make this stuff increasingly difficult. If you are using a test server, evaluate whether you should put ', :require => false' after factory_girl in your gemspec.

The topic is also covered in this google groups thread

Please let us know if any of this helped.