Testing simple STI with FactoryGirl

Question

I have got a class, that is the base of some other classes that specializes the behavior:

class Task < ActiveRecord::Base
  attr_accessible :type, :name, :command
  validates_presence_of :type, :name, :command

  # some methods I would like to test

end

The class CounterTask inherits from Task

class CounterTask < Task 
end

This all works fine until I am trying to test the base class, since it must have a type.

FactoryGirl.define do
  factory :task do
    sequence(:name) { |n| "name_#{n}" }
    sequence(:command) { |n|  "command_#{n}" }
  end
end

How would you test the basic functionality of the superclass?

Shouldn't your test be written so that it tests the functionality, rather than the implementation? In this case that would mean you would test whether `CounterTask` has the attributes and other things it gets from `Task`. If you change your implementation, for example not using STI anymore. Your test could still succeed if your `CounterTask` keeps the same behaviour. — Arjan, Aug 20 '13 at 10:01
That is a good point. I just thought I will save some duplications in the test if I first test the base functionality and then the child classes... Perhaps this might be the solution to my problem. — Mark, Aug 20 '13 at 10:17

score 73 · Accepted Answer · edited Nov 20 '13 at 16:32

73

You can declare the definitions of factories as follow:

FactoryGirl.define do
  factory :task, class: 'Task' do
    shop
    currency
    value 10
  end

  factory :counter_task, parent: :task, class: 'CounterTask' do
  end
end

And now you can test base class isolated from its own factory and the same for each inherited class.

edited Nov 20 '13 at 16:32

Corey Adler

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answered Nov 20 '13 at 16:15

emaxi

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I only needed to pass the `class` option to the child factory to make this work: `factory :counter_task, class: 'CounterTask' do` (no `class` option was necessary for the parent factory either). – gabe Mar 25 '15 at 23:37
1

@gabe Omitting the `class: 'Task'` also works for me, but, `parent: :task` does seem to be significant if you want the properties defined in the task block to be defined when using counter_task. So, with `parent: :task`, `build(:counter_task).value == 10`. If you don't set the parent, `build(:counter_task).value == nil`. – LiamD Jul 20 '16 at 16:09

Testing simple STI with FactoryGirl

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