# frozen_string_literal: true
require 'test/unit'
require_relative 'scheduler'

class TestFiberMutex < Test::Unit::TestCase
  def test_mutex_synchronize
    mutex = Mutex.new

    thread = Thread.new do
      scheduler = Scheduler.new
      Thread.current.scheduler = scheduler

      Fiber.schedule do
        assert_equal Thread.scheduler, scheduler

        mutex.synchronize do
          assert Thread.scheduler
        end
      end
    end

    thread.join
  end

  def test_mutex_interleaved_locking
    mutex = Mutex.new

    thread = Thread.new do
      scheduler = Scheduler.new
      Thread.current.scheduler = scheduler

      Fiber.schedule do
        mutex.lock
        sleep 0.1
        mutex.unlock
      end

      Fiber.schedule do
        mutex.lock
        sleep 0.1
        mutex.unlock
      end

      scheduler.run
    end

    thread.join
  end

  def test_mutex_deadlock
    err = /No live threads left. Deadlock\?/
    assert_in_out_err %W[-I#{__dir__} -], <<-RUBY, ['in synchronize'], err, success: false
    require 'scheduler'
    mutex = Mutex.new

    thread = Thread.new do
      scheduler = Scheduler.new
      Thread.current.scheduler = scheduler

      Fiber.schedule do
        raise unless Thread.scheduler == scheduler

        mutex.synchronize do
          puts 'in synchronize'
          Fiber.yield
        end
      end

      mutex.lock
    end

    thread.join
    RUBY
  end
end