Work around Ruby 2.3.7 bug by defining prepended class methods needed for tests

app/workers/authorized_projects_worker.rb

@@ -2,6 +2,14 @@ class AuthorizedProjectsWorker
   include ApplicationWorker
   prepend WaitableWorker
+  # This is a workaround for a Ruby 2.3.7 bug. rspec-mocks cannot restore the
+  # visibility of prepended modules. See https://github.com/rspec/rspec-mocks/issues/1231
+  # for more details.
+  if Rails.env.test?
+    def self.bulk_perform_and_wait(args_list, timeout: 10)
+    end
+  end
+
   def perform(user_id)
     user = User.find_by(id: user_id)

spec/workers/concerns/waitable_worker_spec.rb

@@ -14,6 +14,12 @@ describe WaitableWorker do
       include ApplicationWorker
       prepend WaitableWorker
+      # This is a workaround for a Ruby 2.3.7 bug. rspec-mocks cannot restore
+      # the visibility of prepended modules. See
+      # https://github.com/rspec/rspec-mocks/issues/1231 for more details.
+      def self.bulk_perform_inline(args_list)
+      end
+
       def perform(i = 0)
         self.class.counter += i
       end