# frozen_string_literal: true

require "abstract_unit"
require "concurrent/atomic/count_down_latch"
require "active_support/concurrency/load_interlock_aware_monitor"

module ActiveSupport
  module Concurrency
    class LoadInterlockAwareMonitorTest < ActiveSupport::TestCase
      def setup
        @monitor = ActiveSupport::Concurrency::LoadInterlockAwareMonitor.new
      end

      def test_entering_with_no_blocking
        assert @monitor.mon_enter
      end

      def test_entering_with_blocking
        load_interlock_latch = Concurrent::CountDownLatch.new
        monitor_latch = Concurrent::CountDownLatch.new

        able_to_use_monitor = false
        able_to_load = false

        thread_with_load_interlock = Thread.new do
          ActiveSupport::Dependencies.interlock.running do
            load_interlock_latch.count_down
            monitor_latch.wait

            @monitor.synchronize do
              able_to_use_monitor = true
            end
          end
        end

        thread_with_monitor_lock = Thread.new do
          @monitor.synchronize do
            monitor_latch.count_down
            load_interlock_latch.wait

            ActiveSupport::Dependencies.interlock.loading do
              able_to_load = true
            end
          end
        end

        thread_with_load_interlock.join
        thread_with_monitor_lock.join

        assert able_to_use_monitor
        assert able_to_load
      end
    end
  end
end
