Lazy-load adapters, fixes #6

lib/active_job/base.rb

+require 'active_job/errors'
 require 'active_job/queue_adapters/inline_adapter'
-require 'active_job/queue_adapters/resque_adapter'
-require 'active_job/queue_adapters/sidekiq_adapter'
-require 'active_job/queue_adapters/sucker_punch_adapter'
+require 'active_support/core_ext/string/inflections'
 
 module ActiveJob
+
   class Base
     cattr_accessor(:queue_adapter)   { ActiveJob::QueueAdapters::InlineAdapter }
     cattr_accessor(:queue_base_name) { "active_jobs" }
@@ -13,10 +13,25 @@ class << self
       def enqueue(*args)
         queue_adapter.queue self, *args
       end
-      
+
       def queue_as(part_name)
         self.queue_name = "#{queue_base_name}_#{part_name}"
       end
+
+      def adapter=(adapter_name)
+        adapter_name = adapter_name.to_s
+        unless %w(inline resque sidekiq sucker_punch).include?(adapter_name)
+          fail ActiveJob::NotImplementedError
+        end
+
+        begin
+          require_relative "queue_adapters/#{adapter_name}_adapter"
+          ActiveJob::Base.queue_adapter = "ActiveJob::QueueAdapters::#{adapter_name.camelize}Adapter".constantize
+        rescue
+          fail ActiveJob::Error.new("#{adapter_name} is missing")
+        end
+      end
     end
+
   end
 end
\ No newline at end of file

lib/active_job/errors.rb

+module ActiveJob
+
+  class NotImplementedError < ::NotImplementedError #:nodoc:
+  end
+
+  class Error < ::StandardError #:nodoc:
+    def initialize(message = nil)
+      super(message)
+    end
+  end
+
+end
\ No newline at end of file

lib/active_job/job_wrappers/resque_wrapper.rb

@@ -2,7 +2,7 @@
 
 require 'active_support/core_ext/enumerable'
 require 'active_support/core_ext/array/access'
-require 'active_support/core_ext/string/inflections'
+
 
 
 module ActiveJob

test/adapters/inline.rb

+ActiveJob::Base.adapter = :inline
\ No newline at end of file

test/adapters/resque.rb

-ActiveJob::Base.queue_adapter = ActiveJob::QueueAdapters::ResqueAdapter
+ActiveJob::Base.adapter = :resque
 Resque.inline = true

test/adapters/sidekiq.rb

 require 'sidekiq/testing/inline'
-ActiveJob::Base.queue_adapter = ActiveJob::QueueAdapters::SidekiqAdapter
+ActiveJob::Base.adapter = :sidekiq

test/adapters/sucker_punch.rb

 require 'sucker_punch/testing/inline'
-ActiveJob::Base.queue_adapter = ActiveJob::QueueAdapters::SuckerPunchAdapter
+ActiveJob::Base.adapter = :sucker_punch

test/cases/adapter_test.rb

+require 'helper'
+
+class AdapterTest < ActiveSupport::TestCase
+  def setup
+    @old_adapter = ActiveJob::Base.queue_adapter
+  end
+
+  test 'should load inline adapter' do
+    ActiveJob::Base.adapter = :inline
+    assert_equal ActiveJob::QueueAdapters::InlineAdapter, ActiveJob::Base.queue_adapter
+  end
+
+  test 'should load resque adapter' do
+    ActiveJob::Base.adapter = :resque
+    assert_equal ActiveJob::QueueAdapters::ResqueAdapter, ActiveJob::Base.queue_adapter
+  end
+
+  test 'should load sidekiq adapter' do
+    ActiveJob::Base.adapter = :sidekiq
+    assert_equal ActiveJob::QueueAdapters::SidekiqAdapter, ActiveJob::Base.queue_adapter
+  end
+
+  test 'should load sucker punch adapter' do
+    ActiveJob::Base.adapter = :sucker_punch
+    assert_equal ActiveJob::QueueAdapters::SuckerPunchAdapter, ActiveJob::Base.queue_adapter
+  end
+
+  def teardown
+    ActiveJob::Base.queue_adapter = @old_adapter
+  end
+end