Missing git add :trollface:

4 files changed, 288 insertions, 0 deletions

diff --git a/railties/lib/rails/queueing.rb b/railties/lib/rails/queueing.rb
new file mode 100644
index 0000000000..b77940f821
--- /dev/null
+++ b/railties/lib/rails/queueing.rb
@@ -0,0 +1,65 @@
+module Rails
+  module Queueing
+    # In test mode, the Rails queue is backed by an Array so that assertions
+    # can be made about its contents. The test queue provides a +contents+
+    # method to make assertions about the queue's contents and a +drain+
+    # method to drain the queue and run the jobs.
+    #
+    # Jobs are run in a separate thread to catch mistakes where code
+    # assumes that the job is run in the same thread.
+    class TestQueue
+      attr_reader :contents
+
+      def initialize
+        @contents = []
+      end
+
+      def drain
+        # run the jobs in a separate thread so assumptions of synchronous
+        # jobs are caught in test mode.
+        t = Thread.new do
+          while job = @contents.pop
+            job.run
+          end
+        end
+        t.join
+      end
+
+      # implement the Queue API
+      def push(object)
+        @contents << object
+      end
+    end
+
+    # The threaded consumer will run jobs in a background thread in
+    # development mode or in a VM where running jobs on a thread in
+    # production mode makes sense.
+    #
+    # When the process exits, the consumer pushes a nil onto the
+    # queue and joins the thread, which will ensure that all jobs
+    # are executed before the process finally dies.
+    class ThreadedConsumer
+      def self.start(queue)
+        new(queue).start
+      end
+
+      def initialize(queue)
+        @queue = queue
+      end
+
+      def start
+        @thread = Thread.new do
+          while job = @queue.pop
+            job.run
+          end
+        end
+        self
+      end
+
+      def shutdown
+        @queue.push nil
+        @thread.join
+      end
+    end
+  end
+end
diff --git a/railties/test/application/queue_test.rb b/railties/test/application/queue_test.rb
new file mode 100644
index 0000000000..667565b031
--- /dev/null
+++ b/railties/test/application/queue_test.rb
@@ -0,0 +1,114 @@
+require 'isolation/abstract_unit'
+require 'rack/test'
+
+module ApplicationTests
+  class GeneratorsTest < ActiveSupport::TestCase
+    include ActiveSupport::Testing::Isolation
+
+    def setup
+      build_app
+      boot_rails
+    end
+
+    def teardown
+      teardown_app
+    end
+
+    def app_const
+      @app_const ||= Class.new(Rails::Application)
+    end
+
+    test "the queue is a TestQueue in test mode" do
+      app("test")
+      assert_kind_of Rails::Queueing::TestQueue, Rails.application.queue
+      assert_kind_of Rails::Queueing::TestQueue, Rails.queue
+    end
+
+    test "the queue is a Queue in development mode" do
+      app("development")
+      assert_kind_of Queue, Rails.application.queue
+      assert_kind_of Queue, Rails.queue
+    end
+
+    test "in development mode, an enqueued job will be processed in a separate thread" do
+      app("development")
+      current = Thread.current
+
+      job = Struct.new(:origin, :target).new(Thread.current)
+      def job.run
+        self.target = Thread.current
+      end
+
+      Rails.queue.push job
+      sleep 0.1
+
+      assert job.target, "The job was run"
+      assert_not_equal job.origin, job.target
+    end
+
+    test "in test mode, explicitly draining the queue will process it in a separate thread" do
+      app("test")
+      current = Thread.current
+
+      job = Struct.new(:origin, :target).new(Thread.current)
+      def job.run
+        self.target = Thread.current
+      end
+
+      Rails.queue.push job
+      Rails.queue.drain
+
+      assert job.target, "The job was run"
+      assert_not_equal job.origin, job.target
+    end
+
+    test "in test mode, the queue can be observed" do
+      app("test")
+
+      job = Class.new(Struct.new(:id)) do
+        def run
+        end
+      end
+
+      jobs = (1..10).map do |id|
+        job.new(id)
+      end
+
+      jobs.each do |job|
+        Rails.queue.push job
+      end
+
+      assert_equal jobs, Rails.queue.contents
+    end
+
+    test "a custom queue implementation can be provided" do
+      add_to_env_config "production", <<-RUBY
+        require "my_queue"
+        config.queue = MyQueue
+      RUBY
+
+      app_file "lib/my_queue.rb", <<-RUBY
+        class MyQueue
+          def push(job)
+            job.run
+          end
+        end
+      RUBY
+
+      app("production")
+
+      assert_kind_of MyQueue, Rails.queue
+
+      job = Class.new(Struct.new(:id, :ran)) do
+        def run
+          self.ran = true
+        end
+      end
+
+      job1 = job.new(1)
+      Rails.queue.push job1
+
+      assert_equal true, job1.ran
+    end
+  end
+end
diff --git a/railties/test/queueing/test_queue_test.rb b/railties/test/queueing/test_queue_test.rb
new file mode 100644
index 0000000000..de30e8cffd
--- /dev/null
+++ b/railties/test/queueing/test_queue_test.rb
@@ -0,0 +1,44 @@
+require 'abstract_unit'
+require 'rails/queueing'
+
+class TestQueueTest < ActiveSupport::TestCase
+  class Job
+    attr_reader :id
+    def initialize(id, &block)
+      @id = id
+      @block = block
+    end
+
+    def run
+      @block.call if @block
+    end
+  end
+
+  def setup
+    @queue = Rails::Queueing::TestQueue.new
+  end
+
+  def test_contents
+    assert_equal [], @queue.contents
+    job = Job.new(1)
+    @queue.push job
+    assert_equal [job], @queue.contents
+  end
+
+  def test_drain
+    t = nil
+    ran = false
+
+    job = Job.new(1) do
+      ran = true
+      t = Thread.current
+    end
+
+    @queue.push job
+    @queue.drain
+
+    assert_equal [], @queue.contents
+    assert ran, "The job runs synchronously when the queue is drained"
+    assert_not_equal t, Thread.current
+  end
+end
diff --git a/railties/test/queueing/threaded_consumer_test.rb b/railties/test/queueing/threaded_consumer_test.rb
new file mode 100644
index 0000000000..d00a67d511
--- /dev/null
+++ b/railties/test/queueing/threaded_consumer_test.rb
@@ -0,0 +1,65 @@
+require 'abstract_unit'
+require 'rails/queueing'
+
+class TestThreadConsumer < ActiveSupport::TestCase
+  class Job
+    attr_reader :id
+    def initialize(id, &block)
+      @id = id
+      @block = block
+    end
+
+    def run
+      @block.call if @block
+    end
+  end
+
+  def setup
+    @queue = Queue.new
+    @consumer = Rails::Queueing::ThreadedConsumer.start(@queue)
+  end
+
+  def teardown
+    @queue.push nil
+  end
+
+  test "the jobs are executed" do
+    ran = false
+
+    job = Job.new(1) do
+      ran = true
+    end
+
+    @queue.push job
+    sleep 0.1
+    assert_equal true, ran
+  end
+
+  test "the jobs are not executed synchronously" do
+    ran = false
+
+    job = Job.new(1) do
+      sleep 0.1
+      ran = true
+    end
+
+    @queue.push job
+    assert_equal false, ran
+  end
+
+  test "shutting down the queue synchronously drains the jobs" do
+    ran = false
+
+    job = Job.new(1) do
+      sleep 0.1
+      ran = true
+    end
+
+    @queue.push job
+    assert_equal false, ran
+
+    @consumer.shutdown
+
+    assert_equal true, ran
+  end
+end