Fix: AppicationController spec

Due to some issues between the rpsec-rails gem and Rails 7, possibly
this:

rspec/rspec-rails#2773

this spec stops working in Rails 7.

To work around this, we move in closer and test the behaviour of the
before action itself asserting that the attribute is correct and using
it via the User is also correct.

We no longer need the `reset_all` calls around every spec as we believe
these are being called for us in later version of rspec-rails:

rspec/rspec-rails#2752

We no longer need the DummyController as it was likely not actually
under test.

We take confidence in the other coverage we have that everything is
working as expected for this feature.

spec/controllers/application_controller_spec.rb

@@ -30,22 +30,12 @@ class DummyController < ApplicationController; end
     end
   end
 
-  describe "before_action" do
-    controller DummyController do
-      def custom_action
-        head 200
-      end
-    end
-
-    before(:each) do
-      routes.draw do
-        get "custom_action" => "dummy#custom_action"
-      end
-    end
-
+  describe "Current attributes before action" do
     context "user is not signed in" do
+      before { allow(controller).to receive(:current_user).and_return(nil) }
+
       it "does not set Current.user_organisation" do
-        get "custom_action"
+        controller.send(:set_organisation_list_and_current_organisation)
 
         expect(Current.user_organisation).to be(nil)
       end
@@ -54,23 +44,22 @@ def custom_action
     context "user is signed in" do
       let(:user) { create(:partner_organisation_user) }
 
-      before do
-        allow(controller).to receive(:current_user).and_return(user)
-      end
+      before { allow(controller).to receive(:current_user).and_return(user) }
 
       it "does not set Current.user_organisation if `current_user_organisation` is not in the session" do
-        get "custom_action"
+        controller.send(:set_organisation_list_and_current_organisation)
 
         expect(Current.user_organisation).to be(nil)
+        expect(controller.current_user.current_organisation_id).to eql(user.primary_organisation.id)
       end
 
       it "sets Current.user_organisation if `current_user_organisation` is in the session" do
-        id = SecureRandom.uuid
-        session[:current_user_organisation] = id
+        session[:current_user_organisation] = "a-fake-id"
 
-        get "custom_action"
+        controller.send(:set_organisation_list_and_current_organisation)
 
-        expect(Current.user_organisation).to be(id)
+        expect(Current.user_organisation).to eql("a-fake-id")
+        expect(controller.current_user.current_organisation_id).to eql("a-fake-id")
       end
     end
   end

spec/rails_helper.rb

@@ -83,12 +83,10 @@
     ActionMailer::Base.delivery_method = :test
     ActionMailer::Base.perform_deliveries = true
     ActionMailer::Base.deliveries = []
-    ActiveSupport::CurrentAttributes.reset_all
   end
 
   config.after(:each) do |example|
     ActionMailer::Base.deliveries.clear
-    ActiveSupport::CurrentAttributes.reset_all
   end
 
   config.before(:each, type: :request) do