Error with nested describe blocks

[pbougie]

I've recently updated my Rails app to 4.2.0 on Ruby 2.2.0. I'm using version 2.1.1 of minitest-rails. In certain situations, I get this error: NameError: wrong constant name ... when nesting describe blocks. Here's my test file:

require 'test_helper'

describe BudgetPolicy do
  before do
    @account = create(:account)
    @account.toggle(:budgets) # activate budgets
    @administrator = create(:employee, account: @account)
  end

  describe "for an administrator" do
    describe "budgets enabled" do
      it { assert_permit @administrator, :budget, :summary }
      it { assert_permit @administrator, :budget, :index }
      it { assert_permit @administrator, :budget, :new }
      it { assert_permit @administrator, :budget, :create }
    end

    describe "budgets disabled" do
      before { @account.toggle(:budgets) } # deactivate budgets

      it { refute_permit @administrator, :budget, :summary }
      it { refute_permit @administrator, :budget, :index }
      it { refute_permit @administrator, :budget, :new }
      it { refute_permit @administrator, :budget, :create }
    end
  end

  ...
end

The error for all 8 tests above is NameError: wrong constant name for an administrator. If I remove a level of describe blocks, all tests pass as expected.

[rpearce]

I don't believe this is a minitest-rails issue.

---

I think I found the source of this problem. Given the following,

class EventPolicyTest < ActiveSupport::TestCase
  Given(:event) { Event.new }

  describe 'for an admin' do
    Given(:user) { users(:admin) }

    describe 'when not bookable' do
      Given(:event) { Event.new(is_bookable: false) }
      Then { assert_permit(user, event, :show) }
    end
  end
end

and that you're probably using the following base permit method,

def permit(user, record, action)
  klass = self.class.superclass.to_s.gsub(/Test/, '')
  klass.constantize.new(user, record).public_send("#{action.to_s}?")
end

then here are the class values, when turned to a string:

[5] pry(#<for an admin::when not bookable>)> self.class.to_s
=> "for an admin::when not bookable"
[6] pry(#<for an admin::when not bookable>)> self.class.superclass.to_s
=> "for an admin"
[7] pry(#<for an admin::when not bookable>)> self.class.superclass.superclass.to_s
=> "EventPolicyTest"

Thus the problem here is that there is too much inheritance.

How to fix:

Change your permit helper to the following:

def permit(user, record, action)
  test_name = self.class.ancestors.select { |a| a.to_s.match(/PolicyTest/) }.first
  klass = test_name.to_s.gsub(/Test/, '')
  klass.constantize.new(user, record).public_send("#{action.to_s}?")
end

Instead of just assuming the superclass is the correct policy you're trying to assert against, specifically select it.

[zenspider]

@rpearce select {...}.first can simply be rewritten to detect {...}

[pbougie]

Unfortunately this didn't work as expected. See solution here.