Shoulda-matchers: Should belong_to with 'optional' not working

[jasonperrone]

4.0.0.rc1

Model Event has this:
belongs_to :event_category, optional: true

Test has this:
should belong_to(:event_category).optional

Get this:
Expected Event to have a belongs_to association called event_category (the association should have been defined with optional: true, but was not)

[derekcannon]

For reference, looks like this is the PR that added that: #1058

[mcmire]

@jasonperrone @derekcannon Do you have anything else in your Event model, such as a presence validation, that could be overriding the behavior of belongs_to in this case?

[derekcannon]

@mcmire I was just referencing the PR. I am not currently on 4.0.0 RC-1, and I haven't personally experienced this problem.

[pareeohnos]

I recently hit this exact same issue and have done some digging - we had a number of models that had optional associations and the tests were passing so the feature does appear to work just fine but it was just on a single model that it was failing.

I isolated the issue down to some additional validation rules which appear to be conflicting with the require checking so at a guess it is just checking for the presence of the association in the validation errors.

The scenario where we were hitting the error was on a User model. The user belongs_to a company which would usually be required, however if the user is a system administrator then the company is optional. Because of this the association has to be defined as belongs_to :company, optional: true but to ensure it is present in every other scenario, we've got something like this:

class User < ApplicationRecord
  ...
  belongs_to :company, optional: true

  validates_presence_of :company, unless: :is_superadmin

  validate :absence_of_company, if: :is_superadmin
  ...

  def absence_of_company
    errors.add(:company_id, 'must be blank for superadmin users') if company_id.present?
  end
end

I would assume then that when the test runs, because the company_id is blank and the is_superadmin is false, the :company has a validation error which shoulda-matchers is expecting to be blank and rather than checking for the correct validation message it is just checking for a validation error? This is just a guess though as I don't know the code.

[mcmire]

Hey @pareeohnos, thanks for the example. That makes perfect sense. I need to think about this further, but just as a quick sketch, I wonder if, for these kinds of scenarios, it would be better to have an additional qualifier to belongs_to which is something like:

it { should belong_to(:company).without_validating_presence }

This way, the matcher wouldn't even bother checking any kind of presence validation, and this would allow you to test presence or absence manually without the matcher interfering.

[pareeohnos]

Ah that would work - I assume that the optional qualifier is just backwards compatible with older version of Rails so that it's just checking that the validation error doesn't exist? If so then yeah I think an additional qualifier would be needed to get around that

[mcmire]

I just merged in a commit that adds a without_validating_presence qualifier to belongs_to and this will be going out in 4.0.

[salmagomaa]

without_validating_presence

[mcmire]

Sorry, I've updated the comment now :)

[kofiasare]

Many thanks @pareeohnos and @mcmire. You helped me.