You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: test_function.rb
    path of file: ./repos/truffleruby/test/mri/tests/fiddle
    
    the code of the file until where you have to start completion: # frozen_string_literal: true
begin
  require_relative 'helper'
rescue LoadError
end

module Fiddle
  class TestFunction < Fiddle::TestCase
    def setup
      super
      Fiddle.last_error = nil
      if WINDOWS
        Fiddle.win32_last_error = nil
        Fiddle.win32_last_socket_error = nil
      end
    end

    def teardown
      # Ensure freeing all closures.
      # See https://github.com/ruby/fiddle/issues/102#issuecomment-1241763091 .
      not_freed_closures = []
      ObjectSpace.each_object(Fiddle::Closure) do |closure|
        not_freed_closures << closure unless closure.freed?
      end
      assert_equal([], not_freed_closures)
    end

    def test_default_abi
      func = Function.new(@libm['sin'], [TYPE_DOUBLE], TYPE_DOUBLE)
      assert_equal Function::DEFAULT, func
    
    def test_nogvl_poll
      # XXX hack to quiet down CI errors on EINTR from r64353
      # [ruby-core:88360] [Misc #14937]
      # Making pipes (and sockets) non-blocking by default would allow
      # us to get rid of POSIX timers / timer pthread
      # https://bugs.ruby-lang.org/issues/14968
      IO.pipe { |r,w| IO.select([r], [w]) }
      begin
        poll = @libc['poll']
      rescue Fiddle::DLError
        omit 'poll(2) not available'
      end
      f = Function.new(poll, [TYPE_VOIDP, TYPE_INT, TYPE_INT], TYPE_INT)

      msec = 200
      t0 = Process.clock_gettime(Process::CLOCK_MONOTONIC, :millisecond)
      th = Thread.new { f.call(nil, 0, msec) }
      n1 = f.call(nil, 0, msec)
      n2 = th.value
      t1 = Process.clock_gettime(Process::CLOCK_MONOTONIC, :millisecond)
      assert_in_delta(msec, t1 - t0, 180, 'slept amount of time')
      assert_equal(0, n1, perror("poll(2) in main-thread"))
      assert_equal(0, n2, perror("poll(2) in sub-thread"))
    end