Rspec - Stub/allow_any_instance_of included module methods is not working

Question

I've been trying to stub a private module method for the whole day now but with not progress.

Here is a snippet of my application controller class

class ApplicationController < ActionController::Base
   include Cesid::Application
end

Cesid > Application.rb

module Cesid
  module Application
    extend ActiveSupport::Concern

    included do
      before_action :track_marketing_suite_cesid, only: [:new]
    end

    private

    def track_marketing_suite_cesid
      return unless id_token_available?
      ## @cesid_auth = Auth.new(@id_token)
      @cesid_auth = Auth.new(id_token)
      return unless @cesid_auth.present? && @cesid_auth.valid?
      @cesid_admin = Admin.where(email: @cesid_auth.email).first_or_initialize
    end

    def id_token_available?
      ## @id_token.present?
      id_token.present?
    end

    def id_token
      @id_token ||= id_token_param
    end

    def id_token_param
      cookies[:id_token]
    end
  end
end

Now, I'm trying to create a simple unit test for the method

id_token_available?

And I am just trying to set the id_token_param to a random value.

I've tried using this code as stated Is there a way to stub a method of an included module with Rspec?

allow_any_instance_of(Cesid).to receive(:id_token_param).and_return('hello')

but I just get this error

NoMethodError:
   undefined method `allow_any_instance_of' for #<RSpec::ExampleGroups::CesidApplication::CesidAuthorizations::GetCesidApplication:0x00007fa3d200c1c0> Did you mean?  allow_mass_assignment_of

Rspec file

require 'rails_helper'

describe Cesid::Application,  :type => :controller  do
  describe 'cesid application' do
    before do
      allow_any_instance_of(ApplicationController).to receive(:id_token_param).and_return('hello')
    end

    it 'returns true if the id_token is present' do
      expect(Cesid::Application.send('id_token_available?')).to eql(true)
    end
  end
end

Rspec version

3.5.4

This is honestly starting to drive me crazy

score 0 · Answer 1 · answered Apr 08 '22 at 10:00

I see three issues:

You call allow_any_instance_of in a context in which it is not defined. allow_any_instance_of can be used in before blocks. I need to see your RSpec code to be more specific.
Actually your code is called on the ApplicationController, not on the module, therefore you need to change your stub to
```
allow_any_instance_of(ApplicationController).to receive(:id_token_param).and_return('hello')
```
Currently id_token_param will not be called at all, because id_token_available? checks the instance variable and not the return value of the id_token method that calls the id_token_param. Just change the id_token_available? to:

def id_token_available? id_token.present? end

Hi, I've updated my comment to follow your feedback and I also added my current rspec file also based on what your suggested. But i'm still getting the same error for `allow_any_instance_of` Any chance you understand what's happening? — rsarmiento, Apr 08 '22 at 14:25

TonyArra · Answer 2 · 2022-04-08T18:42:08.337

There's a much better way of going about this test. The type: :controller metadata on your spec gives you an anonymous controller instance to work with. Here's an example of how you could write this to actually test that the before_action from your module is used:

describe Cesid::Application, type: :controller do
  controller(ApplicationController) do
    def new
      render plain: 'Hello'
    end
  end

  describe 'cesid before_action' do
    before(:each) do
      routes.draw { get 'new' => 'anonymous#new' }
      cookies[:id_token] = id_token
      allow(Auth).to receive(:new).with(id_token)
        .and_return(instance_double(Auth, valid?: false))
      get :new
    end

    context 'when id token is available' do
      let(:id_token) { 'hello' }

      it 'sets @cesid_auth' do
        expect(assigns(:cesid_auth)).to be_present
      end
    end

    context 'when id token is unavailable' do
      let(:id_token) { '' }

      it 'does not set @cesid_auth' do
        expect(assigns(:cesid_auth)).to be_nil
      end
    end
  end
end

Rspec - Stub/allow_any_instance_of included module methods is not working

2 Answers2