Have .queue_as only set queue name for job in question.

lib/active_job/base.rb

@@ -9,8 +9,8 @@ require 'active_job/logging'
 module ActiveJob
   class Base
     extend QueueAdapter
-    extend QueueName
 
+    include QueueName
     include Enqueuing
     include Execution
     include Callbacks

lib/active_job/queue_name.rb

@@ -1,10 +1,18 @@
 module ActiveJob
   module QueueName
-    mattr_accessor(:queue_base_name) { "active_jobs" }
-    mattr_accessor(:queue_name)      { queue_base_name }
+    extend ActiveSupport::Concern
 
-    def queue_as(part_name)
-      self.queue_name = "#{queue_base_name}_#{part_name}"
+    module ClassMethods
+      mattr_accessor(:queue_base_name) { "active_jobs" }
+
+      def queue_as(part_name)
+        self.queue_name = "#{queue_base_name}_#{part_name}"
+      end
+    end
+
+    included do
+      class_attribute :queue_name
+      self.queue_name = queue_base_name
     end
   end
 end

test/cases/queue_naming_test.rb

@@ -9,9 +9,13 @@ class QueueNamingTest < ActiveSupport::TestCase
   test 'name appended in job' do
     begin
       HelloJob.queue_as :greetings
+      LoggingJob.queue_as :bookkeeping
+
+      assert_equal "active_jobs", NestedJob.queue_name
       assert_equal "active_jobs_greetings", HelloJob.queue_name
+      assert_equal "active_jobs_bookkeeping", LoggingJob.queue_name
     ensure
-      HelloJob.queue_name = HelloJob.queue_base_name
+      HelloJob.queue_name = LoggingJob.queue_name = ActiveJob::Base.queue_base_name
     end
   end
 end