rails--rails/activerecord/test/cases/threaded_connections_test.rb

require 'abstract_unit'
require 'models/topic'
require 'models/reply'

unless %w(FrontBase).include? ActiveRecord::Base.connection.adapter_name
  class ThreadedConnectionsTest < ActiveSupport::TestCase
    self.use_transactional_fixtures = false

    fixtures :topics

  def setup
    @connection = ActiveRecord::Base.remove_connection
    @connections = []
    @allow_concurrency = ActiveRecord::Base.allow_concurrency
  end

  def teardown
    # clear the connection cache
    ActiveRecord::Base.send(:clear_all_cached_connections!)
    # set allow_concurrency to saved value
    ActiveRecord::Base.allow_concurrency = @allow_concurrency
    # reestablish old connection
    ActiveRecord::Base.establish_connection(@connection)
  end

  def gather_connections(use_threaded_connections)
    ActiveRecord::Base.allow_concurrency = use_threaded_connections
    ActiveRecord::Base.establish_connection(@connection)

      5.times do
        Thread.new do
          Topic.find :first
          @connections << ActiveRecord::Base.active_connections.values.first
        end.join
      end
    end

    def test_threaded_connections
      gather_connections(true)
      assert_equal @connections.uniq.length, 5
    end

    def test_unthreaded_connections
      gather_connections(false)
      assert_equal @connections.uniq.length, 1
    end
  end
end