test for invalid tokens error

This test follows the steps to reproduce the error in issue #2873.  But I can’t reproduce the error when I remove the original PR fix that adds turbolinks_events.js.  So I cannot confirm that this test can serve as a regression test.

spec/features/dashboard/collection_spec.rb

@@ -1,4 +1,6 @@
 RSpec.describe 'collection', type: :feature, clean_repo: true do
+  include Selectors::Dashboard
+
   let(:user) { create(:user) }
   let(:admin_user) { create(:admin) }
   let(:collection_type) { create(:collection_type, creator_user: user) }
@@ -865,11 +867,16 @@ def get_url_fragment(type)
         end
 
         context "to true, limits available users", js: true do
+          let(:user2) { create(:user) }
           it "to system users filted by select2" do
             visit "/dashboard/collections/#{sharable_collection_id}/edit"
             expect(page).to have_link('Sharing', href: '#sharing')
             click_link('Sharing')
             expect(page).to have_selector(".form-inline.add-users .select2-container")
+            select_user(user2, 'Depositor')
+            click_button('Save')
+            click_link('Sharing')
+            expect(page).to have_selector('td', text: user2.user_key)
           end
         end
 

spec/support/selectors.rb

@@ -5,6 +5,21 @@ def db_item_actions_toggle(item)
         find '.dropdown-toggle'
       end
     end
+
+    # For use with javascript user selector that allows for searching for an existing user
+    # and granting them permission to an object.
+    # @param [User] user to select
+    # @param [String] role granting the user permission (e.g. 'Manager' | 'Depositor' | 'Viewer')
+    def select_user(user, role='Depositor')
+      first('a.select2-choice').click
+      find('.select2-input').set(user.user_key)
+      sleep 1
+      first('div.select2-result-label').click
+      within('div.add-users') do
+        select(role)
+        find('input.edit-collection-add-sharing-button').click
+      end
+    end
   end
 
   module NewTransfers