# coding: US-ASCII
# frozen_string_literal: false
require 'test/unit'
require 'tmpdir'
require "fcntl"
require 'io/nonblock'
require 'pathname'
require 'socket'
require 'stringio'
require 'timeout'
require 'tempfile'
require 'weakref'

class TestIO < Test::Unit::TestCase
  module Feature
    def have_close_on_exec?
      $stdin.close_on_exec?
      true
    rescue NotImplementedError
      false
    end

    def have_nonblock?
      IO.method_defined?("nonblock=")
    end
  end

  include Feature
  extend Feature

  def pipe(wp, rp)
    re, we = nil, nil
    r, w = IO.pipe
    rt = Thread.new do
      begin
        rp.call(r)
      rescue Exception
        r.close
        re = $!
      end
    end
    wt = Thread.new do
      begin
        wp.call(w)
      rescue Exception
        w.close
        we = $!
      end
    end
    flunk("timeout") unless wt.join(10) && rt.join(10)
  ensure
    w&.close
    r&.close
    (wt.kill; wt.join) if wt
    (rt.kill; rt.join) if rt
    raise we if we
    raise re if re
  end

  def with_pipe
    r, w = IO.pipe
    begin
      yield r, w
    ensure
      r.close
      w.close
    end
  end

  def with_read_pipe(content)
    pipe(proc do |w|
      w << content
      w.close
    end, proc do |r|
      yield r
    end)
  end

  def mkcdtmpdir
    Dir.mktmpdir {|d|
      Dir.chdir(d) {
        yield
      }
    }
  end

  def trapping_usr2
    @usr2_rcvd  = 0
    r, w = IO.pipe
    trap(:USR2) do
      w.write([@usr2_rcvd += 1].pack('L'))
    end
    yield r
  ensure
    trap(:USR2, "DEFAULT")
    w&.close
    r&.close
  end

  def test_pipe
    r, w = IO.pipe
    assert_instance_of(IO, r)
    assert_instance_of(IO, w)
    [
      Thread.start{
        w.print "abc"
        w.close
      },
      Thread.start{
        assert_equal("abc", r.read)
        r.close
      }
    ].each{|thr| thr.join}
  end

  def test_binmode_pipe
    EnvUtil.with_default_internal(Encoding::UTF_8) do
      EnvUtil.with_default_external(Encoding::UTF_8) do
        begin
          reader, writer = IO.pipe
          reader.binmode
          writer.binmode

          reader1, writer1 = IO.pipe

          reader2, writer2 = IO.pipe(binmode: true)
          assert_predicate writer, :binmode?
          assert_predicate writer2, :binmode?
          assert_equal writer.binmode?, writer2.binmode?
          assert_equal writer.external_encoding, writer2.external_encoding
          assert_equal writer.internal_encoding, writer2.internal_encoding
          assert_predicate reader, :binmode?
          assert_predicate reader2, :binmode?
          assert_equal reader.binmode?, reader2.binmode?
          assert_equal reader.external_encoding, reader2.external_encoding
          assert_equal reader.internal_encoding, reader2.internal_encoding

          reader3, writer3 = IO.pipe("UTF-8:UTF-8", binmode: true)
          assert_predicate writer3, :binmode?
          assert_equal writer1.external_encoding, writer3.external_encoding
          assert_equal writer1.internal_encoding, writer3.internal_encoding
          assert_predicate reader3, :binmode?
          assert_equal reader1.external_encoding, reader3.external_encoding
          assert_equal reader1.internal_encoding, reader3.internal_encoding

          reader4, writer4 = IO.pipe("UTF-8:UTF-8", binmode: true)
          assert_predicate writer4, :binmode?
          assert_equal writer1.external_encoding, writer4.external_encoding
          assert_equal writer1.internal_encoding, writer4.internal_encoding
          assert_predicate reader4, :binmode?
          assert_equal reader1.external_encoding, reader4.external_encoding
          assert_equal reader1.internal_encoding, reader4.internal_encoding

          reader5, writer5 = IO.pipe("UTF-8", "UTF-8", binmode: true)
          assert_predicate writer5, :binmode?
          assert_equal writer1.external_encoding, writer5.external_encoding
          assert_equal writer1.internal_encoding, writer5.internal_encoding
          assert_predicate reader5, :binmode?
          assert_equal reader1.external_encoding, reader5.external_encoding
          assert_equal reader1.internal_encoding, reader5.internal_encoding
        ensure
          reader.close if reader
          writer.close if writer
          reader1.close if reader1
          writer1.close if writer1
          reader2.close if reader2
          writer2.close if writer2
          reader3.close if reader3
          writer3.close if writer3
          reader4.close if reader4
          writer4.close if writer4
          reader5.close if reader5
          writer5.close if writer5
        end
      end
    end
  end

  def test_pipe_block
    x = nil
    ret = IO.pipe {|r, w|
      x = [r,w]
      assert_instance_of(IO, r)
      assert_instance_of(IO, w)
      [
        Thread.start do
          w.print "abc"
          w.close
        end,
        Thread.start do
          assert_equal("abc", r.read)
        end
      ].each{|thr| thr.join}
      assert_not_predicate(r, :closed?)
      assert_predicate(w, :closed?)
      :foooo
    }
    assert_equal(:foooo, ret)
    assert_predicate(x[0], :closed?)
    assert_predicate(x[1], :closed?)
  end

  def test_pipe_block_close
    4.times {|i|
      x = nil
      IO.pipe {|r, w|
        x = [r,w]
        r.close if (i&1) == 0
        w.close if (i&2) == 0
      }
      assert_predicate(x[0], :closed?)
      assert_predicate(x[1], :closed?)
    }
  end

  def test_gets_rs
    rs = ":"
    pipe(proc do |w|
      w.print "aaa:bbb"
      w.close
    end, proc do |r|
      assert_equal "aaa:", r.gets(rs)
      assert_equal "bbb", r.gets(rs)
      assert_nil r.gets(rs)
      r.close
    end)
  end

  def test_gets_default_rs
    pipe(proc do |w|
      w.print "aaa\nbbb\n"
      w.close
    end, proc do |r|
      assert_equal "aaa\n", r.gets
      assert_equal "bbb\n", r.gets
      assert_nil r.gets
      r.close
    end)
  end

  def test_gets_rs_nil
    pipe(proc do |w|
      w.print "a\n\nb\n\n"
      w.close
    end, proc do |r|
      assert_equal "a\n\nb\n\n", r.gets(nil)
      assert_nil r.gets("")
      r.close
    end)
  end

  def test_gets_rs_377
    pipe(proc do |w|
      w.print "\377xyz"
      w.close
    end, proc do |r|
      r.binmode
      assert_equal("\377", r.gets("\377"), "[ruby-dev:24460]")
      r.close
    end)
  end

  def test_gets_paragraph
    pipe(proc do |w|
      w.print "a\n\nb\n\n"
      w.close
    end, proc do |r|
      assert_equal "a\n\n", r.gets(""), "[ruby-core:03771]"
      assert_equal "b\n\n", r.gets("")
      assert_nil r.gets("")
      r.close
    end)
  end

  def test_gets_chomp_rs
    rs = ":"
    pipe(proc do |w|
      w.print "aaa:bbb"
      w.close
    end, proc do |r|
      assert_equal "aaa", r.gets(rs, chomp: true)
      assert_equal "bbb", r.gets(rs, chomp: true)
      assert_nil r.gets(rs, chomp: true)
      r.close
    end)
  end

  def test_gets_chomp_default_rs
    pipe(proc do |w|
      w.print "aaa\r\nbbb\nccc"
      w.close
    end, proc do |r|
      assert_equal "aaa", r.gets(chomp: true)
      assert_equal "bbb", r.gets(chomp: true)
      assert_equal "ccc", r.gets(chomp: true)
      assert_nil r.gets
      r.close
    end)

    (0..3).each do |i|
      pipe(proc do |w|
        w.write("a" * ((4096 << i) - 4), "\r\n" "a\r\n")
        w.close
      end,
      proc do |r|
        r.gets
        assert_equal "a", r.gets(chomp: true)
        assert_nil r.gets
        r.close
      end)
    end
  end

  def test_gets_chomp_rs_nil
    pipe(proc do |w|
      w.print "a\n\nb\n\n"
      w.close
    end, proc do |r|
      assert_equal "a\n\nb\n", r.gets(nil, chomp: true)
      assert_nil r.gets("")
      r.close
    end)
  end

  def test_gets_chomp_paragraph
    pipe(proc do |w|
      w.print "a\n\nb\n\n"
      w.close
    end, proc do |r|
      assert_equal "a", r.gets("", chomp: true)
      assert_equal "b", r.gets("", chomp: true)
      assert_nil r.gets("", chomp: true)
      r.close
    end)
  end

  def test_gets_limit_extra_arg
    pipe(proc do |w|
      w << "0123456789\n0123456789"
      w.close
    end, proc do |r|
      assert_equal("0123456789\n0", r.gets(nil, 12))
      assert_raise(TypeError) { r.gets(3,nil) }
    end)
  end

  # This test cause SEGV.
  def test_ungetc
    pipe(proc do |w|
      w.close
    end, proc do |r|
      s = "a" * 1000
      assert_raise(IOError, "[ruby-dev:31650]") { 200.times { r.ungetc s } }
    end)
  end

  def test_ungetbyte
    make_tempfile {|t|
      t.open
      t.binmode
      t.ungetbyte(0x41)
      assert_equal(-1, t.pos)
      assert_equal(0x41, t.getbyte)
      t.rewind
      assert_equal(0, t.pos)
      t.ungetbyte("qux")
      assert_equal(-3, t.pos)
      assert_equal("quxfoo\n", t.gets)
      assert_equal(4, t.pos)
      t.set_encoding("utf-8")
      t.ungetbyte(0x89)
      t.ungetbyte(0x8e)
      t.ungetbyte("\xe7")
      t.ungetbyte("\xe7\xb4\x85")
      assert_equal(-2, t.pos)
      assert_equal("\u7d05\u7389bar\n", t.gets)
    }
  end

  def test_each_byte
    pipe(proc do |w|
      w << "abc def"
      w.close
    end, proc do |r|
      r.each_byte {|byte| break if byte == 32 }
      assert_equal("def", r.read, "[ruby-dev:31659]")
    end)
  end

  def test_each_byte_with_seek
    make_tempfile {|t|
      bug5119 = '[ruby-core:38609]'
      i = 0
      open(t.path) do |f|
        f.each_byte {i = f.pos}
      end
      assert_equal(12, i, bug5119)
    }
  end

  def test_each_codepoint
    make_tempfile {|t|
      bug2959 = '[ruby-core:28650]'
      a = ""
      File.open(t, 'rt') {|f|
        f.each_codepoint {|c| a << c}
      }
      assert_equal("foo\nbar\nbaz\n", a, bug2959)
    }
  end

  def test_codepoints
    make_tempfile {|t|
      bug2959 = '[ruby-core:28650]'
      a = ""
      File.open(t, 'rt') {|f|
        assert_warn(/deprecated/) {
          f.codepoints {|c| a << c}
        }
      }
      assert_equal("foo\nbar\nbaz\n", a, bug2959)
    }
  end

  def test_rubydev33072
    t = make_tempfile
    path = t.path
    t.close!
    assert_raise(Errno::ENOENT, "[ruby-dev:33072]") do
      File.read(path, nil, nil, {})
    end
  end

  def with_srccontent(content = "baz")
    src = "src"
    mkcdtmpdir {
      File.open(src, "w") {|f| f << content }
      yield src, content
    }
  end

  def test_copy_stream_small
    with_srccontent("foobar") {|src, content|
      ret = IO.copy_stream(src, "dst")
      assert_equal(content.bytesize, ret)
      assert_equal(content, File.read("dst"))
    }
  end

  def test_copy_stream_append
    with_srccontent("foobar") {|src, content|
      File.open('dst', 'ab') do |dst|
        ret = IO.copy_stream(src, dst)
        assert_equal(content.bytesize, ret)
        assert_equal(content, File.read("dst"))
      end
    }
  end

  def test_copy_stream_smaller
    with_srccontent {|src, content|

      # overwrite by smaller file.
      dst = "dst"
      File.open(dst, "w") {|f| f << "foobar"}

      ret = IO.copy_stream(src, dst)
      assert_equal(content.bytesize, ret)
      assert_equal(content, File.read(dst))

      ret = IO.copy_stream(src, dst, 2)
      assert_equal(2, ret)
      assert_equal(content[0,2], File.read(dst))

      ret = IO.copy_stream(src, dst, 0)
      assert_equal(0, ret)
      assert_equal("", File.read(dst))

      ret = IO.copy_stream(src, dst, nil, 1)
      assert_equal(content.bytesize-1, ret)
      assert_equal(content[1..-1], File.read(dst))
    }
  end

  def test_copy_stream_noent
    with_srccontent {|src, content|
      assert_raise(Errno::ENOENT) {
        IO.copy_stream("nodir/foo", "dst")
      }

      assert_raise(Errno::ENOENT) {
        IO.copy_stream(src, "nodir/bar")
      }
    }
  end

  def test_copy_stream_pipe
    with_srccontent {|src, content|
      pipe(proc do |w|
        ret = IO.copy_stream(src, w)
        assert_equal(content.bytesize, ret)
        w.close
      end, proc do |r|
        assert_equal(content, r.read)
      end)
    }
  end

  def test_copy_stream_write_pipe
    with_srccontent {|src, content|
      with_pipe {|r, w|
        w.close
        assert_raise(IOError) { IO.copy_stream(src, w) }
      }
    }
  end

  def with_pipecontent
    mkcdtmpdir {
      yield "abc"
    }
  end

  def test_copy_stream_pipe_to_file
    with_pipecontent {|pipe_content|
      dst = "dst"
      with_read_pipe(pipe_content) {|r|
        ret = IO.copy_stream(r, dst)
        assert_equal(pipe_content.bytesize, ret)
        assert_equal(pipe_content, File.read(dst))
      }
    }
  end

  def test_copy_stream_read_pipe
    with_pipecontent {|pipe_content|
      with_read_pipe(pipe_content) {|r1|
        assert_equal("a", r1.getc)
        pipe(proc do |w2|
          w2.sync = false
          w2 << "def"
          ret = IO.copy_stream(r1, w2)
          assert_equal(2, ret)
          w2.close
        end, proc do |r2|
          assert_equal("defbc", r2.read)
        end)
      }

      with_read_pipe(pipe_content) {|r1|
        assert_equal("a", r1.getc)
        pipe(proc do |w2|
          w2.sync = false
          w2 << "def"
          ret = IO.copy_stream(r1, w2, 1)
          assert_equal(1, ret)
          w2.close
        end, proc do |r2|
          assert_equal("defb", r2.read)
        end)
      }

      with_read_pipe(pipe_content) {|r1|
        assert_equal("a", r1.getc)
        pipe(proc do |w2|
          ret = IO.copy_stream(r1, w2)
          assert_equal(2, ret)
          w2.close
        end, proc do |r2|
          assert_equal("bc", r2.read)
        end)
      }

      with_read_pipe(pipe_content) {|r1|
        assert_equal("a", r1.getc)
        pipe(proc do |w2|
          ret = IO.copy_stream(r1, w2, 1)
          assert_equal(1, ret)
          w2.close
        end, proc do |r2|
          assert_equal("b", r2.read)
        end)
      }

      with_read_pipe(pipe_content) {|r1|
        assert_equal("a", r1.getc)
        pipe(proc do |w2|
          ret = IO.copy_stream(r1, w2, 0)
          assert_equal(0, ret)
          w2.close
        end, proc do |r2|
          assert_equal("", r2.read)
        end)
      }

      pipe(proc do |w1|
        w1 << "abc"
        w1 << "def"
        w1.close
      end, proc do |r1|
        assert_equal("a", r1.getc)
        pipe(proc do |w2|
          ret = IO.copy_stream(r1, w2)
          assert_equal(5, ret)
          w2.close
        end, proc do |r2|
          assert_equal("bcdef", r2.read)
        end)
      end)
    }
  end

  def test_copy_stream_file_to_pipe
    with_srccontent {|src, content|
      pipe(proc do |w|
        ret = IO.copy_stream(src, w, 1, 1)
        assert_equal(1, ret)
        w.close
      end, proc do |r|
        assert_equal(content[1,1], r.read)
      end)
    }
  end

  if have_nonblock?
    def test_copy_stream_no_busy_wait
      skip "MJIT has busy wait on GC. This sometimes fails with --jit." if RubyVM::MJIT.enabled?
      skip "multiple threads already active" if Thread.list.size > 1

      msg = 'r58534 [ruby-core:80969] [Backport #13533]'
      IO.pipe do |r,w|
        r.nonblock = true
        assert_cpu_usage_low(msg, stop: ->{w.close}) do
          IO.copy_stream(r, IO::NULL)
        end
      end
    end

    def test_copy_stream_pipe_nonblock
      mkcdtmpdir {
        with_read_pipe("abc") {|r1|
          assert_equal("a", r1.getc)
          with_pipe {|r2, w2|
            begin
              w2.nonblock = true
            rescue Errno::EBADF
              skip "nonblocking IO for pipe is not implemented"
            end
            s = w2.syswrite("a" * 100000)
            t = Thread.new { sleep 0.1; r2.read }
            ret = IO.copy_stream(r1, w2)
            w2.close
            assert_equal(2, ret)
            assert_equal("a" * s + "bc", t.value)
          }
        }
      }
    end
  end

  def with_bigcontent
    yield "abc" * 123456
  end

  def with_bigsrc
    mkcdtmpdir {
      with_bigcontent {|bigcontent|
        bigsrc = "bigsrc"
        File.open("bigsrc", "w") {|f| f << bigcontent }
        yield bigsrc, bigcontent
      }
    }
  end

  def test_copy_stream_bigcontent
    with_bigsrc {|bigsrc, bigcontent|
      ret = IO.copy_stream(bigsrc, "bigdst")
      assert_equal(bigcontent.bytesize, ret)
      assert_equal(bigcontent, File.read("bigdst"))
    }
  end

  def test_copy_stream_bigcontent_chop
    with_bigsrc {|bigsrc, bigcontent|
      ret = IO.copy_stream(bigsrc, "bigdst", nil, 100)
      assert_equal(bigcontent.bytesize-100, ret)
      assert_equal(bigcontent[100..-1], File.read("bigdst"))
    }
  end

  def test_copy_stream_bigcontent_mid
    with_bigsrc {|bigsrc, bigcontent|
      ret = IO.copy_stream(bigsrc, "bigdst", 30000, 100)
      assert_equal(30000, ret)
      assert_equal(bigcontent[100, 30000], File.read("bigdst"))
    }
  end

  def test_copy_stream_bigcontent_fpos
    with_bigsrc {|bigsrc, bigcontent|
      File.open(bigsrc) {|f|
        begin
          assert_equal(0, f.pos)
          ret = IO.copy_stream(f, "bigdst", nil, 10)
          assert_equal(bigcontent.bytesize-10, ret)
          assert_equal(bigcontent[10..-1], File.read("bigdst"))
          assert_equal(0, f.pos)
          ret = IO.copy_stream(f, "bigdst", 40, 30)
          assert_equal(40, ret)
          assert_equal(bigcontent[30, 40], File.read("bigdst"))
          assert_equal(0, f.pos)
        rescue NotImplementedError
          #skip "pread(2) is not implemented."
        end
      }
    }
  end

  def test_copy_stream_closed_pipe
    with_srccontent {|src,|
      with_pipe {|r, w|
        w.close
        assert_raise(IOError) { IO.copy_stream(src, w) }
      }
    }
  end

  def with_megacontent
    yield "abc" * 1234567
  end

  def with_megasrc
    mkcdtmpdir {
      with_megacontent {|megacontent|
        megasrc = "megasrc"
        File.open(megasrc, "w") {|f| f << megacontent }
        yield megasrc, megacontent
      }
    }
  end

  if have_nonblock?
    def test_copy_stream_megacontent_nonblock
      with_megacontent {|megacontent|
        with_pipe {|r1, w1|
          with_pipe {|r2, w2|
            begin
              r1.nonblock = true
              w2.nonblock = true
            rescue Errno::EBADF
              skip "nonblocking IO for pipe is not implemented"
            end
            t1 = Thread.new { w1 << megacontent; w1.close }
            t2 = Thread.new { r2.read }
            t3 = Thread.new {
              ret = IO.copy_stream(r1, w2)
              assert_equal(megacontent.bytesize, ret)
              w2.close
            }
            _, t2_value, _ = assert_join_threads([t1, t2, t3])
            assert_equal(megacontent, t2_value)
          }
        }
      }
    end
  end

  def test_copy_stream_megacontent_pipe_to_file
    with_megasrc {|megasrc, megacontent|
      with_pipe {|r1, w1|
        with_pipe {|r2, w2|
          t1 = Thread.new { w1 << megacontent; w1.close }
          t2 = Thread.new { r2.read }
          t3 = Thread.new {
            ret = IO.copy_stream(r1, w2)
            assert_equal(megacontent.bytesize, ret)
            w2.close
          }
          _, t2_value, _ = assert_join_threads([t1, t2, t3])
          assert_equal(megacontent, t2_value)
        }
      }
    }
  end

  def test_copy_stream_megacontent_file_to_pipe
    with_megasrc {|megasrc, megacontent|
      with_pipe {|r, w|
        t1 = Thread.new { r.read }
        t2 = Thread.new {
          ret = IO.copy_stream(megasrc, w)
          assert_equal(megacontent.bytesize, ret)
          w.close
        }
        t1_value, _ = assert_join_threads([t1, t2])
        assert_equal(megacontent, t1_value)
      }
    }
  end

  def test_copy_stream_rbuf
    mkcdtmpdir {
      begin
        pipe(proc do |w|
          File.open("foo", "w") {|f| f << "abcd" }
          File.open("foo") {|f|
            f.read(1)
            assert_equal(3, IO.copy_stream(f, w, 10, 1))
          }
          w.close
        end, proc do |r|
          assert_equal("bcd", r.read)
        end)
      rescue NotImplementedError
        skip "pread(2) is not implemtented."
      end
    }
  end

  def with_socketpair
    s1, s2 = UNIXSocket.pair
    begin
      yield s1, s2
    ensure
      s1.close unless s1.closed?
      s2.close unless s2.closed?
    end
  end

  def test_copy_stream_socket1
    with_srccontent("foobar") {|src, content|
      with_socketpair {|s1, s2|
        ret = IO.copy_stream(src, s1)
        assert_equal(content.bytesize, ret)
        s1.close
        assert_equal(content, s2.read)
      }
    }
  end if defined? UNIXSocket

  def test_copy_stream_socket2
    with_bigsrc {|bigsrc, bigcontent|
      with_socketpair {|s1, s2|
        t1 = Thread.new { s2.read }
        t2 = Thread.new {
          ret = IO.copy_stream(bigsrc, s1)
          assert_equal(bigcontent.bytesize, ret)
          s1.close
        }
        result, _ = assert_join_threads([t1, t2])
        assert_equal(bigcontent, result)
      }
    }
  end if defined? UNIXSocket

  def test_copy_stream_socket3
    with_bigsrc {|bigsrc, bigcontent|
      with_socketpair {|s1, s2|
        t1 = Thread.new { s2.read }
        t2 = Thread.new {
          ret = IO.copy_stream(bigsrc, s1, 10000)
          assert_equal(10000, ret)
          s1.close
        }
        result, _ = assert_join_threads([t1, t2])
        assert_equal(bigcontent[0,10000], result)
      }
    }
  end if defined? UNIXSocket

  def test_copy_stream_socket4
    with_bigsrc {|bigsrc, bigcontent|
      File.open(bigsrc) {|f|
        assert_equal(0, f.pos)
        with_socketpair {|s1, s2|
          t1 = Thread.new { s2.read }
          t2 = Thread.new {
            ret = IO.copy_stream(f, s1, nil, 100)
            assert_equal(bigcontent.bytesize-100, ret)
            assert_equal(0, f.pos)
            s1.close
          }
          result, _ = assert_join_threads([t1, t2])
          assert_equal(bigcontent[100..-1], result)
        }
      }
    }
  end if defined? UNIXSocket

  def test_copy_stream_socket5
    with_bigsrc {|bigsrc, bigcontent|
      File.open(bigsrc) {|f|
        assert_equal(bigcontent[0,100], f.read(100))
        assert_equal(100, f.pos)
        with_socketpair {|s1, s2|
          t1 = Thread.new { s2.read }
          t2 = Thread.new {
            ret = IO.copy_stream(f, s1)
            assert_equal(bigcontent.bytesize-100, ret)
            assert_equal(bigcontent.length, f.pos)
            s1.close
          }
          result, _ = assert_join_threads([t1, t2])
          assert_equal(bigcontent[100..-1], result)
        }
      }
    }
  end if defined? UNIXSocket

  def test_copy_stream_socket6
    mkcdtmpdir {
      megacontent = "abc" * 1234567
      File.open("megasrc", "w") {|f| f << megacontent }

      with_socketpair {|s1, s2|
        begin
          s1.nonblock = true
        rescue Errno::EBADF
          skip "nonblocking IO for pipe is not implemented"
        end
        t1 = Thread.new { s2.read }
        t2 = Thread.new {
          ret = IO.copy_stream("megasrc", s1)
          assert_equal(megacontent.bytesize, ret)
          s1.close
        }
        result, _ = assert_join_threads([t1, t2])
        assert_equal(megacontent, result)
      }
    }
  end if defined? UNIXSocket

  def test_copy_stream_socket7
    GC.start
    mkcdtmpdir {
      megacontent = "abc" * 1234567
      File.open("megasrc", "w") {|f| f << megacontent }

      with_socketpair {|s1, s2|
        begin
          s1.nonblock = true
        rescue Errno::EBADF
          skip "nonblocking IO for pipe is not implemented"
        end
        trapping_usr2 do |rd|
          nr = 30
          begin
            pid = fork do
              s1.close
              IO.select([s2])
              Process.kill(:USR2, Process.ppid)
              buf = String.new(capacity: 16384)
              nil while s2.read(16384, buf)
            end
            s2.close
            nr.times do
              assert_equal megacontent.bytesize, IO.copy_stream("megasrc", s1)
            end
            assert_equal(1, rd.read(4).unpack1('L'))
          ensure
            s1.close
            _, status = Process.waitpid2(pid) if pid
          end
          assert_predicate(status, :success?)
        end
      }
    }
  end if defined? UNIXSocket and IO.method_defined?("nonblock=")

  def test_copy_stream_strio
    src = StringIO.new("abcd")
    dst = StringIO.new
    ret = IO.copy_stream(src, dst)
    assert_equal(4, ret)
    assert_equal("abcd", dst.string)
    assert_equal(4, src.pos)
  end

  def test_copy_stream_strio_len
    src = StringIO.new("abcd")
    dst = StringIO.new
    ret = IO.copy_stream(src, dst, 3)
    assert_equal(3, ret)
    assert_equal("abc", dst.string)
    assert_equal(3, src.pos)
  end

  def test_copy_stream_strio_off
    src = StringIO.new("abcd")
    with_pipe {|r, w|
      assert_raise(ArgumentError) {
        IO.copy_stream(src, w, 3, 1)
      }
    }
  end

  def test_copy_stream_fname_to_strio
    mkcdtmpdir {
      File.open("foo", "w") {|f| f << "abcd" }
      src = "foo"
      dst = StringIO.new
      ret = IO.copy_stream(src, dst, 3)
      assert_equal(3, ret)
      assert_equal("abc", dst.string)
    }
  end

  def test_copy_stream_strio_to_fname
    mkcdtmpdir {
      # StringIO to filename
      src = StringIO.new("abcd")
      ret = IO.copy_stream(src, "fooo", 3)
      assert_equal(3, ret)
      assert_equal("abc", File.read("fooo"))
      assert_equal(3, src.pos)
    }
  end

  def test_copy_stream_io_to_strio
    mkcdtmpdir {
      # IO to StringIO
      File.open("bar", "w") {|f| f << "abcd" }
      File.open("bar") {|src|
        dst = StringIO.new
        ret = IO.copy_stream(src, dst, 3)
        assert_equal(3, ret)
        assert_equal("abc", dst.string)
        assert_equal(3, src.pos)
      }
    }
  end

  def test_copy_stream_strio_to_io
    mkcdtmpdir {
      # StringIO to IO
      src = StringIO.new("abcd")
      ret = File.open("baz", "w") {|dst|
        IO.copy_stream(src, dst, 3)
      }
      assert_equal(3, ret)
      assert_equal("abc", File.read("baz"))
      assert_equal(3, src.pos)
    }
  end

  def test_copy_stream_strio_to_tempfile
    bug11015 = '[ruby-core:68676] [Bug #11015]'
    # StringIO to Tempfile
    src = StringIO.new("abcd")
    dst = Tempfile.new("baz")
    ret = IO.copy_stream(src, dst)
    assert_equal(4, ret)
    pos = dst.pos
    dst.rewind
    assert_equal("abcd", dst.read)
    assert_equal(4, pos, bug11015)
  ensure
    dst.close!
  end

  def test_copy_stream_pathname_to_pathname
    bug11199 = '[ruby-dev:49008] [Bug #11199]'
    mkcdtmpdir {
      File.open("src", "w") {|f| f << "ok" }
      src = Pathname.new("src")
      dst = Pathname.new("dst")
      IO.copy_stream(src, dst)
      assert_equal("ok", IO.read("dst"), bug11199)
    }
  end

  def test_copy_stream_write_in_binmode
    bug8767 = '[ruby-core:56518] [Bug #8767]'
    mkcdtmpdir {
      EnvUtil.with_default_internal(Encoding::UTF_8) do
        # StringIO to object with to_path
        bytes = "\xDE\xAD\xBE\xEF".force_encoding(Encoding::ASCII_8BIT)
        src = StringIO.new(bytes)
        dst = Object.new
        def dst.to_path
          "qux"
        end
        assert_nothing_raised(bug8767) {
          IO.copy_stream(src, dst)
        }
        assert_equal(bytes, File.binread("qux"), bug8767)
        assert_equal(4, src.pos, bug8767)
      end
    }
  end

  def test_copy_stream_read_in_binmode
    bug8767 = '[ruby-core:56518] [Bug #8767]'
    mkcdtmpdir {
      EnvUtil.with_default_internal(Encoding::UTF_8) do
        # StringIO to object with to_path
        bytes = "\xDE\xAD\xBE\xEF".force_encoding(Encoding::ASCII_8BIT)
        File.binwrite("qux", bytes)
        dst = StringIO.new
        src = Object.new
        def src.to_path
          "qux"
        end
        assert_nothing_raised(bug8767) {
          IO.copy_stream(src, dst)
        }
        assert_equal(bytes, dst.string.b, bug8767)
        assert_equal(4, dst.pos, bug8767)
      end
    }
  end

  class Rot13IO
    def initialize(io)
      @io = io
    end

    def readpartial(*args)
      ret = @io.readpartial(*args)
      ret.tr!('a-zA-Z', 'n-za-mN-ZA-M')
      ret
    end

    def write(str)
      @io.write(str.tr('a-zA-Z', 'n-za-mN-ZA-M'))
    end

    def to_io
      @io
    end
  end

  def test_copy_stream_io_to_rot13
    mkcdtmpdir {
      File.open("bar", "w") {|f| f << "vex" }
      File.open("bar") {|src|
        File.open("baz", "w") {|dst0|
          dst = Rot13IO.new(dst0)
          ret = IO.copy_stream(src, dst, 3)
          assert_equal(3, ret)
        }
        assert_equal("irk", File.read("baz"))
      }
    }
  end

  def test_copy_stream_rot13_to_io
    mkcdtmpdir {
      File.open("bar", "w") {|f| f << "flap" }
      File.open("bar") {|src0|
        src = Rot13IO.new(src0)
        File.open("baz", "w") {|dst|
          ret = IO.copy_stream(src, dst, 4)
          assert_equal(4, ret)
        }
      }
      assert_equal("sync", File.read("baz"))
    }
  end

  def test_copy_stream_rot13_to_rot13
    mkcdtmpdir {
      File.open("bar", "w") {|f| f << "bin" }
      File.open("bar") {|src0|
        src = Rot13IO.new(src0)
        File.open("baz", "w") {|dst0|
          dst = Rot13IO.new(dst0)
          ret = IO.copy_stream(src, dst, 3)
          assert_equal(3, ret)
        }
      }
      assert_equal("bin", File.read("baz"))
    }
  end

  def test_copy_stream_strio_flush
    with_pipe {|r, w|
      w.sync = false
      w.write "zz"
      src = StringIO.new("abcd")
      IO.copy_stream(src, w)
      t1 = Thread.new {
        w.close
      }
      t2 = Thread.new { r.read }
      _, result = assert_join_threads([t1, t2])
      assert_equal("zzabcd", result)
    }
  end

  def test_copy_stream_strio_rbuf
    pipe(proc do |w|
      w << "abcd"
      w.close
    end, proc do |r|
      assert_equal("a", r.read(1))
      sio = StringIO.new
      IO.copy_stream(r, sio)
      assert_equal("bcd", sio.string)
    end)
  end

  def test_copy_stream_src_wbuf
    mkcdtmpdir {
      pipe(proc do |w|
        File.open("foe", "w+") {|f|
          f.write "abcd\n"
          f.rewind
          f.write "xy"
          IO.copy_stream(f, w)
        }
        assert_equal("xycd\n", File.read("foe"))
        w.close
      end, proc do |r|
        assert_equal("cd\n", r.read)
        r.close
      end)
    }
  end

  class Bug5237
    attr_reader :count
    def initialize
      @count = 0
    end

    def read(bytes, buffer)
      @count += 1
      buffer.replace "this is a test"
      nil
    end
  end

  def test_copy_stream_broken_src_read_eof
    src = Bug5237.new
    dst = StringIO.new
    assert_equal 0, src.count
    th = Thread.new { IO.copy_stream(src, dst) }
    flunk("timeout") unless th.join(10)
    assert_equal 1, src.count
  end

  def test_copy_stream_dst_rbuf
    mkcdtmpdir {
      pipe(proc do |w|
        w << "xyz"
        w.close
      end, proc do |r|
        File.open("fom", "w+b") {|f|
          f.write "abcd\n"
          f.rewind
          assert_equal("abc", f.read(3))
          f.ungetc "c"
          IO.copy_stream(r, f)
        }
        assert_equal("abxyz", File.read("fom"))
      end)
    }
  end

  def test_copy_stream_to_duplex_io
    result = IO.pipe {|a,w|
      th = Thread.start {w.puts "yes"; w.close}
      IO.popen([EnvUtil.rubybin, '-pe$_="#$.:#$_"'], "r+") {|b|
        IO.copy_stream(a, b)
        b.close_write
        assert_join_threads([th])
        b.read
      }
    }
    assert_equal("1:yes\n", result)
  end

  def ruby(*args)
    args = ['-e', '$>.write($<.read)'] if args.empty?
    ruby = EnvUtil.rubybin
    opts = {}
    if defined?(Process::RLIMIT_NPROC)
      lim = Process.getrlimit(Process::RLIMIT_NPROC)[1]
      opts[:rlimit_nproc] = [lim, 2048].min
    end
    f = IO.popen([ruby] + args, 'r+', opts)
    pid = f.pid
    yield(f)
  ensure
    f.close unless !f || f.closed?
    begin
      Process.wait(pid)
    rescue Errno::ECHILD, Errno::ESRCH
    end
  end

  def test_try_convert
    assert_equal(STDOUT, IO.try_convert(STDOUT))
    assert_equal(nil, IO.try_convert("STDOUT"))
  end

  def test_ungetc2
    f = false
    pipe(proc do |w|
      Thread.pass until f
      w.write("1" * 10000)
      w.close
    end, proc do |r|
      r.ungetc("0" * 10000)
      f = true
      assert_equal("0" * 10000 + "1" * 10000, r.read)
    end)
  end

  def test_write_with_multiple_arguments
    pipe(proc do |w|
      w.write("foo", "bar")
      w.close
    end, proc do |r|
      assert_equal("foobar", r.read)
    end)
  end

  def test_write_with_multiple_arguments_and_buffer
    mkcdtmpdir do
      line = "x"*9+"\n"
      file = "test.out"
      open(file, "wb") do |w|
        w.write(line)
        assert_equal(11, w.write(line, "\n"))
      end
      open(file, "rb") do |r|
        assert_equal([line, line, "\n"], r.readlines)
      end

      line = "x"*99+"\n"
      open(file, "wb") do |w|
        w.write(line*81)        # 8100 bytes
        assert_equal(100, w.write("a"*99, "\n"))
      end
      open(file, "rb") do |r|
        81.times {assert_equal(line, r.gets)}
        assert_equal("a"*99+"\n", r.gets)
      end
    end
  end

  def test_write_with_many_arguments
    [1023, 1024].each do |n|
      pipe(proc do |w|
        w.write(*(["a"] * n))
        w.close
      end, proc do |r|
        assert_equal("a" * n, r.read)
      end)
    end
  end

  def test_write_with_multiple_nonstring_arguments
    assert_in_out_err([], "STDOUT.write(:foo, :bar)", ["foobar"])
  end

  def test_write_buffered_with_multiple_arguments
    out, err, (_, status) = EnvUtil.invoke_ruby(["-e", "sleep 0.1;puts 'foo'"], "", true, true) do |_, o, e, i|
      [o.read, e.read, Process.waitpid2(i)]
    end
    assert_predicate(status, :success?)
    assert_equal("foo\n", out)
    assert_empty(err)
  end

  def test_write_no_args
    IO.pipe do |r, w|
      assert_equal 0, w.write, '[ruby-core:86285] [Bug #14338]'
      assert_equal :wait_readable, r.read_nonblock(1, exception: false)
    end
  end

  def test_write_non_writable
    with_pipe do |r, w|
      assert_raise(IOError) do
        r.write "foobarbaz"
      end
    end
  end

  def test_dup
    ruby do |f|
      begin
        f2 = f.dup
        f.puts "foo"
        f2.puts "bar"
        f.close_write
        f2.close_write
        assert_equal("foo\nbar\n", f.read)
        assert_equal("", f2.read)
      ensure
        f2.close
      end
    end
  end

  def test_dup_many
    opts = {}
    opts[:rlimit_nofile] = 1024 if defined?(Process::RLIMIT_NOFILE)
    assert_separately([], <<-'End', opts)
      a = []
      assert_raise(Errno::EMFILE, Errno::ENFILE, Errno::ENOMEM) do
        loop {a << IO.pipe}
      end
      assert_raise(Errno::EMFILE, Errno::ENFILE, Errno::ENOMEM) do
        loop {a << [a[-1][0].dup, a[-1][1].dup]}
      end
    End
  end

  def test_inspect
    with_pipe do |r, w|
      assert_match(/^#<IO:fd \d+>$/, r.inspect)
      r.freeze
      assert_match(/^#<IO:fd \d+>$/, r.inspect)
    end
  end

  def test_readpartial
    pipe(proc do |w|
      w.write "foobarbaz"
      w.close
    end, proc do |r|
      assert_raise(ArgumentError) { r.readpartial(-1) }
      assert_equal("fooba", r.readpartial(5))
      r.readpartial(5, s = "")
      assert_equal("rbaz", s)
    end)
  end

  def test_readpartial_lock
    with_pipe do |r, w|
      s = ""
      t = Thread.new { r.readpartial(5, s) }
      Thread.pass until t.stop?
      assert_raise(RuntimeError) { s.clear }
      w.write "foobarbaz"
      w.close
      assert_equal("fooba", t.value)
    end
  end

  def test_readpartial_pos
    mkcdtmpdir {
      open("foo", "w") {|f| f << "abc" }
      open("foo") {|f|
        f.seek(0)
        assert_equal("ab", f.readpartial(2))
        assert_equal(2, f.pos)
      }
    }
  end

  def test_readpartial_with_not_empty_buffer
    pipe(proc do |w|
      w.write "foob"
      w.close
    end, proc do |r|
      r.readpartial(5, s = "01234567")
      assert_equal("foob", s)
    end)
  end

  def test_readpartial_buffer_error
    with_pipe do |r, w|
      s = ""
      t = Thread.new { r.readpartial(5, s) }
      Thread.pass until t.stop?
      t.kill
      t.value
      assert_equal("", s)
    end
  end if /cygwin/ !~ RUBY_PLATFORM

  def test_read
    pipe(proc do |w|
      w.write "foobarbaz"
      w.close
    end, proc do |r|
      assert_raise(ArgumentError) { r.read(-1) }
      assert_equal("fooba", r.read(5))
      r.read(nil, s = "")
      assert_equal("rbaz", s)
    end)
  end

  def test_read_lock
    with_pipe do |r, w|
      s = ""
      t = Thread.new { r.read(5, s) }
      Thread.pass until t.stop?
      assert_raise(RuntimeError) { s.clear }
      w.write "foobarbaz"
      w.close
      assert_equal("fooba", t.value)
    end
  end

  def test_read_with_not_empty_buffer
    pipe(proc do |w|
      w.write "foob"
      w.close
    end, proc do |r|
      r.read(nil, s = "01234567")
      assert_equal("foob", s)
    end)
  end

  def test_read_buffer_error
    with_pipe do |r, w|
      s = ""
      t = Thread.new { r.read(5, s) }
      Thread.pass until t.stop?
      t.kill
      t.value
      assert_equal("", s)
    end
    with_pipe do |r, w|
      s = "xxx"
      t = Thread.new {r.read(2, s)}
      Thread.pass until t.stop?
      t.kill
      t.value
      assert_equal("xxx", s)
    end
  end if /cygwin/ !~ RUBY_PLATFORM

  def test_write_nonblock
    pipe(proc do |w|
      w.write_nonblock(1)
      w.close
    end, proc do |r|
      assert_equal("1", r.read)
    end)
  end

  def test_read_nonblock_with_not_empty_buffer
    with_pipe {|r, w|
      w.write "foob"
      w.close
      r.read_nonblock(5, s = "01234567")
      assert_equal("foob", s)
    }
  end

  def test_write_nonblock_simple_no_exceptions
    pipe(proc do |w|
      w.write_nonblock('1', exception: false)
      w.close
    end, proc do |r|
      assert_equal("1", r.read)
    end)
  end

  def test_read_nonblock_error
    with_pipe {|r, w|
      begin
        r.read_nonblock 4096
      rescue Errno::EWOULDBLOCK
        assert_kind_of(IO::WaitReadable, $!)
      end
    }

    with_pipe {|r, w|
      begin
        r.read_nonblock 4096, ""
      rescue Errno::EWOULDBLOCK
        assert_kind_of(IO::WaitReadable, $!)
      end
    }
  end if have_nonblock?

  def test_read_nonblock_invalid_exception
    with_pipe {|r, w|
      assert_raise(ArgumentError) {r.read_nonblock(4096, exception: 1)}
    }
  end if have_nonblock?

  def test_read_nonblock_no_exceptions
    skip '[ruby-core:90895] MJIT worker may leave fd open in a forked child' if RubyVM::MJIT.enabled? # TODO: consider acquiring GVL from MJIT worker.
    with_pipe {|r, w|
      assert_equal :wait_readable, r.read_nonblock(4096, exception: false)
      w.puts "HI!"
      assert_equal "HI!\n", r.read_nonblock(4096, exception: false)
      w.close
      assert_equal nil, r.read_nonblock(4096, exception: false)
    }
  end if have_nonblock?

  def test_read_nonblock_with_buffer_no_exceptions
    with_pipe {|r, w|
      assert_equal :wait_readable, r.read_nonblock(4096, "", exception: false)
      w.puts "HI!"
      buf = "buf"
      value = r.read_nonblock(4096, buf, exception: false)
      assert_equal value, "HI!\n"
      assert_same(buf, value)
      w.close
      assert_equal nil, r.read_nonblock(4096, "", exception: false)
    }
  end if have_nonblock?

  def test_write_nonblock_error
    with_pipe {|r, w|
      begin
        loop {
          w.write_nonblock "a"*100000
        }
      rescue Errno::EWOULDBLOCK
        assert_kind_of(IO::WaitWritable, $!)
      end
    }
  end if have_nonblock?

  def test_write_nonblock_invalid_exception
    with_pipe {|r, w|
      assert_raise(ArgumentError) {w.write_nonblock(4096, exception: 1)}
    }
  end if have_nonblock?

  def test_write_nonblock_no_exceptions
    with_pipe {|r, w|
      loop {
        ret = w.write_nonblock("a"*100000, exception: false)
        if ret.is_a?(Symbol)
          assert_equal :wait_writable, ret
          break
        end
      }
    }
  end if have_nonblock?

  def test_gets
    pipe(proc do |w|
      w.write "foobarbaz"
      w.close
    end, proc do |r|
      assert_equal("", r.gets(0))
      assert_equal("foobarbaz", r.gets(9))
    end)
  end

  def test_close_read
    ruby do |f|
      f.close_read
      f.write "foobarbaz"
      assert_raise(IOError) { f.read }
      assert_nothing_raised(IOError) {f.close_read}
      assert_nothing_raised(IOError) {f.close}
      assert_nothing_raised(IOError) {f.close_read}
    end
  end

  def test_close_read_pipe
    with_pipe do |r, w|
      r.close_read
      assert_raise(Errno::EPIPE) { w.write "foobarbaz" }
      assert_nothing_raised(IOError) {r.close_read}
      assert_nothing_raised(IOError) {r.close}
      assert_nothing_raised(IOError) {r.close_read}
    end
  end

  def test_write_epipe_nosync
    assert_separately([], <<-"end;")
      r, w = IO.pipe
      r.close
      w.sync = false
      assert_raise(Errno::EPIPE) {
        loop { w.write "a" }
      }
    end;
  end

  def test_close_read_non_readable
    with_pipe do |r, w|
      assert_raise(IOError) do
        w.close_read
      end
    end
  end

  def test_close_write
    ruby do |f|
      f.write "foobarbaz"
      f.close_write
      assert_equal("foobarbaz", f.read)
      assert_nothing_raised(IOError) {f.close_write}
      assert_nothing_raised(IOError) {f.close}
      assert_nothing_raised(IOError) {f.close_write}
    end
  end

  def test_close_write_non_readable
    with_pipe do |r, w|
      assert_raise(IOError) do
        r.close_write
      end
    end
  end

  def test_close_read_write_separately
    bug = '[ruby-list:49598]'
    (1..10).each do |i|
      assert_nothing_raised(IOError, "#{bug} trying ##{i}") do
        IO.popen(EnvUtil.rubybin, "r+") {|f|
          th = Thread.new {f.close_write}
          f.close_read
          th.join
        }
      end
    end
  end

  def test_pid
    IO.pipe {|r, w|
      assert_equal(nil, r.pid)
      assert_equal(nil, w.pid)
    }

    begin
      pipe = IO.popen(EnvUtil.rubybin, "r+")
      pid1 = pipe.pid
      pipe.puts "p $$"
      pipe.close_write
      pid2 = pipe.read.chomp.to_i
      assert_equal(pid2, pid1)
      assert_equal(pid2, pipe.pid)
    ensure
      pipe.close
    end
    assert_raise(IOError) { pipe.pid }
  end

  def test_pid_after_close_read
    pid1 = pid2 = nil
    IO.popen("exit ;", "r+") do |io|
      pid1 = io.pid
      io.close_read
      pid2 = io.pid
    end
    assert_not_nil(pid1)
    assert_equal(pid1, pid2)
  end

  def make_tempfile
    t = Tempfile.new("test_io")
    t.binmode
    t.puts "foo"
    t.puts "bar"
    t.puts "baz"
    t.close
    if block_given?
      begin
        yield t
      ensure
        t.close(true)
      end
    else
      t
    end
  end

  def test_set_lineno
    make_tempfile {|t|
      assert_separately(["-", t.path], <<-SRC)
        open(ARGV[0]) do |f|
          assert_equal(0, $.)
          f.gets; assert_equal(1, $.)
          f.gets; assert_equal(2, $.)
          f.lineno = 1000; assert_equal(2, $.)
          f.gets; assert_equal(1001, $.)
          f.gets; assert_equal(1001, $.)
          f.rewind; assert_equal(1001, $.)
          f.gets; assert_equal(1, $.)
          f.gets; assert_equal(2, $.)
          f.gets; assert_equal(3, $.)
          f.gets; assert_equal(3, $.)
        end
      SRC
    }
  end

  def test_set_lineno_gets
    pipe(proc do |w|
      w.puts "foo"
      w.puts "bar"
      w.puts "baz"
      w.close
    end, proc do |r|
      r.gets; assert_equal(1, $.)
      r.gets; assert_equal(2, $.)
      r.lineno = 1000; assert_equal(2, $.)
      r.gets; assert_equal(1001, $.)
      r.gets; assert_equal(1001, $.)
    end)
  end

  def test_set_lineno_readline
    pipe(proc do |w|
      w.puts "foo"
      w.puts "bar"
      w.puts "baz"
      w.close
    end, proc do |r|
      r.readline; assert_equal(1, $.)
      r.readline; assert_equal(2, $.)
      r.lineno = 1000; assert_equal(2, $.)
      r.readline; assert_equal(1001, $.)
      assert_raise(EOFError) { r.readline }
    end)
  end

  def test_each_char
    pipe(proc do |w|
      w.puts "foo"
      w.puts "bar"
      w.puts "baz"
      w.close
    end, proc do |r|
      a = []
      r.each_char {|c| a << c }
      assert_equal(%w(f o o) + ["\n"] + %w(b a r) + ["\n"] + %w(b a z) + ["\n"], a)
    end)
  end

  def test_lines
    verbose, $VERBOSE = $VERBOSE, nil
    pipe(proc do |w|
      w.puts "foo"
      w.puts "bar"
      w.puts "baz"
      w.close
    end, proc do |r|
      e = nil
      assert_warn(/deprecated/) {
        e = r.lines
      }
      assert_equal("foo\n", e.next)
      assert_equal("bar\n", e.next)
      assert_equal("baz\n", e.next)
      assert_raise(StopIteration) { e.next }
    end)
  ensure
    $VERBOSE = verbose
  end

  def test_bytes
    verbose, $VERBOSE = $VERBOSE, nil
    pipe(proc do |w|
      w.binmode
      w.puts "foo"
      w.puts "bar"
      w.puts "baz"
      w.close
    end, proc do |r|
      e = nil
      assert_warn(/deprecated/) {
        e = r.bytes
      }
      (%w(f o o) + ["\n"] + %w(b a r) + ["\n"] + %w(b a z) + ["\n"]).each do |c|
        assert_equal(c.ord, e.next)
      end
      assert_raise(StopIteration) { e.next }
    end)
  ensure
    $VERBOSE = verbose
  end

  def test_chars
    verbose, $VERBOSE = $VERBOSE, nil
    pipe(proc do |w|
      w.puts "foo"
      w.puts "bar"
      w.puts "baz"
      w.close
    end, proc do |r|
      e = nil
      assert_warn(/deprecated/) {
        e = r.chars
      }
      (%w(f o o) + ["\n"] + %w(b a r) + ["\n"] + %w(b a z) + ["\n"]).each do |c|
        assert_equal(c, e.next)
      end
      assert_raise(StopIteration) { e.next }
    end)
  ensure
    $VERBOSE = verbose
  end

  def test_readbyte
    pipe(proc do |w|
      w.binmode
      w.puts "foo"
      w.puts "bar"
      w.puts "baz"
      w.close
    end, proc do |r|
      r.binmode
      (%w(f o o) + ["\n"] + %w(b a r) + ["\n"] + %w(b a z) + ["\n"]).each do |c|
        assert_equal(c.ord, r.readbyte)
      end
      assert_raise(EOFError) { r.readbyte }
    end)
  end

  def test_readchar
    pipe(proc do |w|
      w.puts "foo"
      w.puts "bar"
      w.puts "baz"
      w.close
    end, proc do |r|
      (%w(f o o) + ["\n"] + %w(b a r) + ["\n"] + %w(b a z) + ["\n"]).each do |c|
        assert_equal(c, r.readchar)
      end
      assert_raise(EOFError) { r.readchar }
    end)
  end

  def test_close_on_exec
    ruby do |f|
      assert_equal(true, f.close_on_exec?)
      f.close_on_exec = false
      assert_equal(false, f.close_on_exec?)
      f.close_on_exec = true
      assert_equal(true, f.close_on_exec?)
      f.close_on_exec = false
      assert_equal(false, f.close_on_exec?)
    end

    with_pipe do |r, w|
      assert_equal(true, r.close_on_exec?)
      r.close_on_exec = false
      assert_equal(false, r.close_on_exec?)
      r.close_on_exec = true
      assert_equal(true, r.close_on_exec?)
      r.close_on_exec = false
      assert_equal(false, r.close_on_exec?)

      assert_equal(true, w.close_on_exec?)
      w.close_on_exec = false
      assert_equal(false, w.close_on_exec?)
      w.close_on_exec = true
      assert_equal(true, w.close_on_exec?)
      w.close_on_exec = false
      assert_equal(false, w.close_on_exec?)
    end
  end if have_close_on_exec?

  def test_pos
    make_tempfile {|t|
      open(t.path, IO::RDWR|IO::CREAT|IO::TRUNC, 0600) do |f|
        f.write "Hello"
        assert_equal(5, f.pos)
      end
      open(t.path, IO::RDWR|IO::CREAT|IO::TRUNC, 0600) do |f|
        f.sync = true
        f.read
        f.write "Hello"
        assert_equal(5, f.pos)
      end
    }
  end

  def test_pos_with_getc
    _bug6179 = '[ruby-core:43497]'
    make_tempfile {|t|
      ["", "t", "b"].each do |mode|
        open(t.path, "w#{mode}") do |f|
          f.write "0123456789\n"
        end

        open(t.path, "r#{mode}") do |f|
          assert_equal 0, f.pos, "mode=r#{mode}"
          assert_equal '0', f.getc, "mode=r#{mode}"
          assert_equal 1, f.pos, "mode=r#{mode}"
          assert_equal '1', f.getc, "mode=r#{mode}"
          assert_equal 2, f.pos, "mode=r#{mode}"
          assert_equal '2', f.getc, "mode=r#{mode}"
          assert_equal 3, f.pos, "mode=r#{mode}"
          assert_equal '3', f.getc, "mode=r#{mode}"
          assert_equal 4, f.pos, "mode=r#{mode}"
          assert_equal '4', f.getc, "mode=r#{mode}"
        end
      end
    }
  end

  def can_seek_data(f)
    if /linux/ =~ RUBY_PLATFORM
      require "-test-/file"
      # lseek(2)
      case Bug::File::Fs.fsname(f.path)
      when "btrfs"
        return true if (Etc.uname[:release].split('.').map(&:to_i) <=> [3,1]) >= 0
      when "ocfs"
        return true if (Etc.uname[:release].split('.').map(&:to_i) <=> [3,2]) >= 0
      when "xfs"
        return true if (Etc.uname[:release].split('.').map(&:to_i) <=> [3,5]) >= 0
      when "ext4"
        return true if (Etc.uname[:release].split('.').map(&:to_i) <=> [3,8]) >= 0
      when "tmpfs"
        return true if (Etc.uname[:release].split('.').map(&:to_i) <=> [3,8]) >= 0
      end
    end
    false
  end

  def test_seek
    make_tempfile {|t|
      open(t.path) { |f|
        f.seek(9)
        assert_equal("az\n", f.read)
      }

      open(t.path) { |f|
        f.seek(9, IO::SEEK_SET)
        assert_equal("az\n", f.read)
      }

      open(t.path) { |f|
        f.seek(-4, IO::SEEK_END)
        assert_equal("baz\n", f.read)
      }

      open(t.path) { |f|
        assert_equal("foo\n", f.gets)
        f.seek(2, IO::SEEK_CUR)
        assert_equal("r\nbaz\n", f.read)
      }

      if defined?(IO::SEEK_DATA)
        open(t.path) { |f|
          break unless can_seek_data(f)
          assert_equal("foo\n", f.gets)
          f.seek(0, IO::SEEK_DATA)
          assert_equal("foo\nbar\nbaz\n", f.read)
        }
        open(t.path, 'r+') { |f|
          break unless can_seek_data(f)
          f.seek(100*1024, IO::SEEK_SET)
          f.print("zot\n")
          f.seek(50*1024, IO::SEEK_DATA)
          assert_operator(f.pos, :>=, 50*1024)
          assert_match(/\A\0*zot\n\z/, f.read)
        }
      end

      if defined?(IO::SEEK_HOLE)
        open(t.path) { |f|
          break unless can_seek_data(f)
          assert_equal("foo\n", f.gets)
          f.seek(0, IO::SEEK_HOLE)
          assert_operator(f.pos, :>, 20)
          f.seek(100*1024, IO::SEEK_HOLE)
          assert_equal("", f.read)
        }
      end
    }
  end

  def test_seek_symwhence
    make_tempfile {|t|
      open(t.path) { |f|
        f.seek(9, :SET)
        assert_equal("az\n", f.read)
      }

      open(t.path) { |f|
        f.seek(-4, :END)
        assert_equal("baz\n", f.read)
      }

      open(t.path) { |f|
        assert_equal("foo\n", f.gets)
        f.seek(2, :CUR)
        assert_equal("r\nbaz\n", f.read)
      }

      if defined?(IO::SEEK_DATA)
        open(t.path) { |f|
          break unless can_seek_data(f)
          assert_equal("foo\n", f.gets)
          f.seek(0, :DATA)
          assert_equal("foo\nbar\nbaz\n", f.read)
        }
        open(t.path, 'r+') { |f|
          break unless can_seek_data(f)
          f.seek(100*1024, :SET)
          f.print("zot\n")
          f.seek(50*1024, :DATA)
          assert_operator(f.pos, :>=, 50*1024)
          assert_match(/\A\0*zot\n\z/, f.read)
        }
      end

      if defined?(IO::SEEK_HOLE)
        open(t.path) { |f|
          break unless can_seek_data(f)
          assert_equal("foo\n", f.gets)
          f.seek(0, :HOLE)
          assert_operator(f.pos, :>, 20)
          f.seek(100*1024, :HOLE)
          assert_equal("", f.read)
        }
      end
    }
  end

  def test_sysseek
    make_tempfile {|t|
      open(t.path) do |f|
        f.sysseek(-4, IO::SEEK_END)
        assert_equal("baz\n", f.read)
      end

      open(t.path) do |f|
        a = [f.getc, f.getc, f.getc]
        a.reverse_each {|c| f.ungetc c }
        assert_raise(IOError) { f.sysseek(1) }
      end
    }
  end

  def test_syswrite
    make_tempfile {|t|
      open(t.path, "w") do |f|
        o = Object.new
        def o.to_s; "FOO\n"; end
        f.syswrite(o)
      end
      assert_equal("FOO\n", File.read(t.path))
    }
  end

  def test_sysread
    make_tempfile {|t|
      open(t.path) do |f|
        a = [f.getc, f.getc, f.getc]
        a.reverse_each {|c| f.ungetc c }
        assert_raise(IOError) { f.sysread(1) }
      end
    }
  end

  def test_sysread_with_not_empty_buffer
    pipe(proc do |w|
      w.write "foob"
      w.close
    end, proc do |r|
      r.sysread( 5, s = "01234567" )
      assert_equal( "foob", s )
    end)
  end

  def test_flag
    make_tempfile {|t|
      assert_raise(ArgumentError) do
        open(t.path, "z") { }
      end

      assert_raise(ArgumentError) do
        open(t.path, "rr") { }
      end

      assert_raise(ArgumentError) do
        open(t.path, "rbt") { }
      end
    }
  end

  def test_sysopen
    make_tempfile {|t|
      fd = IO.sysopen(t.path)
      assert_kind_of(Integer, fd)
      f = IO.for_fd(fd)
      assert_equal("foo\nbar\nbaz\n", f.read)
      f.close

      fd = IO.sysopen(t.path, "w", 0666)
      assert_kind_of(Integer, fd)
      if defined?(Fcntl::F_GETFL)
        f = IO.for_fd(fd)
      else
        f = IO.for_fd(fd, 0666)
      end
      f.write("FOO\n")
      f.close

      fd = IO.sysopen(t.path, "r")
      assert_kind_of(Integer, fd)
      f = IO.for_fd(fd)
      assert_equal("FOO\n", f.read)
      f.close
    }
  end

  def try_fdopen(fd, autoclose = true, level = 50)
    if level > 0
      begin
        1.times {return try_fdopen(fd, autoclose, level - 1)}
      ensure
        GC.start
      end
    else
      WeakRef.new(IO.for_fd(fd, autoclose: autoclose))
    end
  end

  def test_autoclose
    feature2250 = '[ruby-core:26222]'
    pre = 'ft2250'

    Dir.mktmpdir {|d|
      t = open("#{d}/#{pre}", "w")
      f = IO.for_fd(t.fileno)
      assert_equal(true, f.autoclose?)
      f.autoclose = false
      assert_equal(false, f.autoclose?)
      f.close
      assert_nothing_raised(Errno::EBADF, feature2250) {t.close}

      t = open("#{d}/#{pre}", "w")
      f = IO.for_fd(t.fileno, autoclose: false)
      assert_equal(false, f.autoclose?)
      f.autoclose = true
      assert_equal(true, f.autoclose?)
      f.close
      assert_raise(Errno::EBADF, feature2250) {t.close}
    }
  end

  def test_autoclose_true_closed_by_finalizer
    # http://ci.rvm.jp/results/trunk-mjit@silicon-docker/1465760
    # http://ci.rvm.jp/results/trunk-mjit@silicon-docker/1469765
    skip 'this randomly fails with MJIT' if RubyVM::MJIT.enabled?

    feature2250 = '[ruby-core:26222]'
    pre = 'ft2250'
    t = Tempfile.new(pre)
    w = try_fdopen(t.fileno)
    begin
      w.close
      begin
        t.close
      rescue Errno::EBADF
      end
      skip "expect IO object was GC'ed but not recycled yet"
    rescue WeakRef::RefError
      assert_raise(Errno::EBADF, feature2250) {t.close}
    end
  ensure
    t&.close!
  end

  def test_autoclose_false_closed_by_finalizer
    feature2250 = '[ruby-core:26222]'
    pre = 'ft2250'
    t = Tempfile.new(pre)
    w = try_fdopen(t.fileno, false)
    begin
      w.close
      t.close
      skip "expect IO object was GC'ed but not recycled yet"
    rescue WeakRef::RefError
      assert_nothing_raised(Errno::EBADF, feature2250) {t.close}
    end
  ensure
    t.close!
  end

  def test_open_redirect
    o = Object.new
    def o.to_open; self; end
    assert_equal(o, open(o))
    o2 = nil
    open(o) do |f|
      o2 = f
    end
    assert_equal(o, o2)
  end

  def test_open_pipe
    open("|" + EnvUtil.rubybin, "r+") do |f|
      f.puts "puts 'foo'"
      f.close_write
      assert_equal("foo\n", f.read)
    end
  end

  def test_read_command
    assert_equal("foo\n", IO.read("|echo foo"))
    assert_raise(Errno::ENOENT, Errno::EINVAL) do
      File.read("|#{EnvUtil.rubybin} -e puts")
    end
    assert_raise(Errno::ENOENT, Errno::EINVAL) do
      File.binread("|#{EnvUtil.rubybin} -e puts")
    end
    assert_raise(Errno::ENOENT, Errno::EINVAL) do
      Class.new(IO).read("|#{EnvUtil.rubybin} -e puts")
    end
    assert_raise(Errno::ENOENT, Errno::EINVAL) do
      Class.new(IO).binread("|#{EnvUtil.rubybin} -e puts")
    end
    assert_raise(Errno::ESPIPE) do
      IO.read("|echo foo", 1, 1)
    end
  end

  def test_reopen
    make_tempfile {|t|
      open(__FILE__) do |f|
        f.gets
        assert_nothing_raised {
          f.reopen(t.path)
          assert_equal("foo\n", f.gets)
        }
      end

      open(__FILE__) do |f|
        f.gets
        f2 = open(t.path)
        begin
          f2.gets
          assert_nothing_raised {
            f.reopen(f2)
            assert_equal("bar\n", f.gets, '[ruby-core:24240]')
          }
        ensure
          f2.close
        end
      end

      open(__FILE__) do |f|
        f2 = open(t.path)
        begin
          f.reopen(f2)
          assert_equal("foo\n", f.gets)
          assert_equal("bar\n", f.gets)
          f.reopen(f2)
          assert_equal("baz\n", f.gets, '[ruby-dev:39479]')
        ensure
          f2.close
        end
      end
    }
  end

  def test_reopen_inherit
    mkcdtmpdir {
      system(EnvUtil.rubybin, '-e', <<-"End")
        f = open("out", "w")
        STDOUT.reopen(f)
        STDERR.reopen(f)
        system(#{EnvUtil.rubybin.dump}, '-e', 'STDOUT.print "out"')
        system(#{EnvUtil.rubybin.dump}, '-e', 'STDERR.print "err"')
      End
      assert_equal("outerr", File.read("out"))
    }
  end

  def test_reopen_stdio
    mkcdtmpdir {
      fname = 'bug11319'
      File.write(fname, 'hello')
      system(EnvUtil.rubybin, '-e', "STDOUT.reopen('#{fname}', 'w+')")
      assert_equal('', File.read(fname))
    }
  end

  def test_reopen_mode
    feature7067 = '[ruby-core:47694]'
    make_tempfile {|t|
      open(__FILE__) do |f|
        assert_nothing_raised {
          f.reopen(t.path, "r")
          assert_equal("foo\n", f.gets)
        }
      end

      open(__FILE__) do |f|
        assert_nothing_raised(feature7067) {
          f.reopen(t.path, File::RDONLY)
          assert_equal("foo\n", f.gets)
        }
      end
    }
  end

  def test_reopen_opt
    feature7103 = '[ruby-core:47806]'
    make_tempfile {|t|
      open(__FILE__) do |f|
        assert_nothing_raised(feature7103) {
          f.reopen(t.path, "r", binmode: true)
        }
        assert_equal("foo\n", f.gets)
      end

      open(__FILE__) do |f|
        assert_nothing_raised(feature7103) {
          f.reopen(t.path, autoclose: false)
        }
        assert_equal("foo\n", f.gets)
      end
    }
  end

  def make_tempfile_for_encoding
    t = make_tempfile
    open(t.path, "rb+:utf-8") {|f| f.puts "\u7d05\u7389bar\n"}
    if block_given?
      yield t
    else
      t
    end
  ensure
    t&.close(true) if block_given?
  end

  def test_reopen_encoding
    make_tempfile_for_encoding {|t|
      open(__FILE__) {|f|
        f.reopen(t.path, "r:utf-8")
        s = f.gets
        assert_equal(Encoding::UTF_8, s.encoding)
        assert_equal("\u7d05\u7389bar\n", s)
      }

      open(__FILE__) {|f|
        f.reopen(t.path, "r:UTF-8:EUC-JP")
        s = f.gets
        assert_equal(Encoding::EUC_JP, s.encoding)
        assert_equal("\xB9\xC8\xB6\xCCbar\n".force_encoding(Encoding::EUC_JP), s)
      }
    }
  end

  def test_reopen_opt_encoding
    feature7103 = '[ruby-core:47806]'
    make_tempfile_for_encoding {|t|
      open(__FILE__) {|f|
        assert_nothing_raised(feature7103) {f.reopen(t.path, encoding: "ASCII-8BIT")}
        s = f.gets
        assert_equal(Encoding::ASCII_8BIT, s.encoding)
        assert_equal("\xe7\xb4\x85\xe7\x8e\x89bar\n", s)
      }

      open(__FILE__) {|f|
        assert_nothing_raised(feature7103) {f.reopen(t.path, encoding: "UTF-8:EUC-JP")}
        s = f.gets
        assert_equal(Encoding::EUC_JP, s.encoding)
        assert_equal("\xB9\xC8\xB6\xCCbar\n".force_encoding(Encoding::EUC_JP), s)
      }
    }
  end

  bug11320 = '[ruby-core:69780] [Bug #11320]'
  ["UTF-8", "EUC-JP", "Shift_JIS"].each do |enc|
    define_method("test_reopen_nonascii(#{enc})") do
      mkcdtmpdir do
        fname = "\u{30eb 30d3 30fc}".encode(enc)
        File.write(fname, '')
        assert_file.exist?(fname)
        stdin = $stdin.dup
        begin
          assert_nothing_raised(Errno::ENOENT, "#{bug11320}: #{enc}") {
            $stdin.reopen(fname, 'r')
          }
        ensure
          $stdin.reopen(stdin)
          stdin.close
        end
      end
    end
  end

  def test_foreach
    a = []
    IO.foreach("|" + EnvUtil.rubybin + " -e 'puts :foo; puts :bar; puts :baz'") {|x| a << x }
    assert_equal(["foo\n", "bar\n", "baz\n"], a)

    a = []
    IO.foreach("|" + EnvUtil.rubybin + " -e 'puts :zot'", :open_args => ["r"]) {|x| a << x }
    assert_equal(["zot\n"], a)

    make_tempfile {|t|
      a = []
      IO.foreach(t.path) {|x| a << x }
      assert_equal(["foo\n", "bar\n", "baz\n"], a)

      a = []
      IO.foreach(t.path, {:mode => "r" }) {|x| a << x }
      assert_equal(["foo\n", "bar\n", "baz\n"], a)

      a = []
      IO.foreach(t.path, {:open_args => [] }) {|x| a << x }
      assert_equal(["foo\n", "bar\n", "baz\n"], a)

      a = []
      IO.foreach(t.path, {:open_args => ["r"] }) {|x| a << x }
      assert_equal(["foo\n", "bar\n", "baz\n"], a)

      a = []
      IO.foreach(t.path, "b") {|x| a << x }
      assert_equal(["foo\nb", "ar\nb", "az\n"], a)

      a = []
      IO.foreach(t.path, 3) {|x| a << x }
      assert_equal(["foo", "\n", "bar", "\n", "baz", "\n"], a)

      a = []
      IO.foreach(t.path, "b", 3) {|x| a << x }
      assert_equal(["foo", "\nb", "ar\n", "b", "az\n"], a)

      bug = '[ruby-dev:31525]'
      assert_raise(ArgumentError, bug) {IO.foreach}

      a = nil
      assert_nothing_raised(ArgumentError, bug) {a = IO.foreach(t.path).to_a}
      assert_equal(["foo\n", "bar\n", "baz\n"], a, bug)

      bug6054 = '[ruby-dev:45267]'
      assert_raise_with_message(IOError, /not opened for reading/, bug6054) do
        IO.foreach(t.path, mode:"w").next
      end
    }
  end

  def test_s_readlines
    make_tempfile {|t|
      assert_equal(["foo\n", "bar\n", "baz\n"], IO.readlines(t.path))
      assert_equal(["foo\nb", "ar\nb", "az\n"], IO.readlines(t.path, "b"))
      assert_equal(["fo", "o\n", "ba", "r\n", "ba", "z\n"], IO.readlines(t.path, 2))
      assert_equal(["fo", "o\n", "b", "ar", "\nb", "az", "\n"], IO.readlines(t.path, "b", 2))
    }
  end

  def test_printf
    pipe(proc do |w|
      printf(w, "foo %s baz\n", "bar")
      w.close_write
    end, proc do |r|
      assert_equal("foo bar baz\n", r.read)
    end)
  end

  def test_print
    make_tempfile {|t|
      assert_in_out_err(["-", t.path],
                        "print while $<.gets",
                        %w(foo bar baz), [])
    }
  end

  def test_print_separators
    EnvUtil.suppress_warning {$, = ':'}
    $\ = "\n"
    pipe(proc do |w|
      w.print('a')
      w.print('a','b','c')
      w.close
    end, proc do |r|
      assert_equal("a\n", r.gets)
      assert_equal("a:b:c\n", r.gets)
      assert_nil r.gets
      r.close
    end)
  ensure
    $, = nil
    $\ = nil
  end

  def test_putc
    pipe(proc do |w|
      w.putc "A"
      w.putc "BC"
      w.putc 68
      w.close_write
    end, proc do |r|
      assert_equal("ABD", r.read)
    end)

    assert_in_out_err([], "putc 65", %w(A), [])
  end

  def test_puts_recursive_array
    a = ["foo"]
    a << a
    pipe(proc do |w|
      w.puts a
      w.close
    end, proc do |r|
      assert_equal("foo\n[...]\n", r.read)
    end)
  end

  def test_puts_parallel
    skip "not portable"
    pipe(proc do |w|
      threads = []
      100.times do
        threads << Thread.new { w.puts "hey" }
      end
      threads.each(&:join)
      w.close
    end, proc do |r|
      assert_equal("hey\n" * 100, r.read)
    end)
  end

  def test_puts_old_write
    capture = String.new
    def capture.write(str)
      self << str
    end

    capture.clear
    assert_warning(/[.#]write is outdated/) do
      stdout, $stdout = $stdout, capture
      puts "hey"
    ensure
      $stdout = stdout
    end
    assert_equal("hey\n", capture)
  end

  def test_display
    pipe(proc do |w|
      "foo".display(w)
      w.close
    end, proc do |r|
      assert_equal("foo", r.read)
    end)

    assert_in_out_err([], "'foo'.display", %w(foo), [])
  end

  def test_set_stdout
    assert_raise(TypeError) { $> = Object.new }

    assert_in_out_err([], "$> = $stderr\nputs 'foo'", [], %w(foo))

    assert_separately(%w[-Eutf-8], "#{<<~"begin;"}\n#{<<~"end;"}")
    begin;
      alias $\u{6a19 6e96 51fa 529b} $stdout
      x = eval("class X\u{307b 3052}; self; end".encode("euc-jp"))
      assert_raise_with_message(TypeError, /\\$\u{6a19 6e96 51fa 529b} must.*, X\u{307b 3052} given/) do
        $\u{6a19 6e96 51fa 529b} = x.new
      end
    end;
  end

  def test_initialize
    return unless defined?(Fcntl::F_GETFL)

    make_tempfile {|t|
      fd = IO.sysopen(t.path, "w")
      assert_kind_of(Integer, fd)
      %w[r r+ w+ a+].each do |mode|
        assert_raise(Errno::EINVAL, "#{mode} [ruby-dev:38571]") {IO.new(fd, mode)}
      end
      f = IO.new(fd, "w")
      f.write("FOO\n")
      f.close

      assert_equal("FOO\n", File.read(t.path))
    }
  end

  def test_reinitialize
    make_tempfile {|t|
      f = open(t.path)
      begin
        assert_raise(RuntimeError) do
          f.instance_eval { initialize }
        end
      ensure
        f.close
      end
    }
  end

  def test_new_with_block
    assert_in_out_err([], "r, w = IO.pipe; r.autoclose=false; IO.new(r.fileno) {}.close", [], /^.+$/)
    n = "IO\u{5165 51fa 529b}"
    c = eval("class #{n} < IO; self; end")
    IO.pipe do |r, w|
      assert_warning(/#{n}/) {
        r.autoclose=false
        io = c.new(r.fileno) {}
        io.close
      }
    end
  end

  def test_readline2
    assert_in_out_err(["-e", <<-SRC], "foo\nbar\nbaz\n", %w(foo bar baz end), [])
      puts readline
      puts readline
      puts readline
      begin
        puts readline
      rescue EOFError
        puts "end"
      end
    SRC
  end

  def test_readlines
    assert_in_out_err(["-e", "p readlines"], "foo\nbar\nbaz\n",
                      ["[\"foo\\n\", \"bar\\n\", \"baz\\n\"]"], [])
  end

  def test_s_read
    make_tempfile {|t|
      assert_equal("foo\nbar\nbaz\n", File.read(t.path))
      assert_equal("foo\nba", File.read(t.path, 6))
      assert_equal("bar\n", File.read(t.path, 4, 4))
    }
  end

  def test_uninitialized
    assert_raise(IOError) { IO.allocate.print "" }
  end

  def test_nofollow
    # O_NOFOLLOW is not standard.
    mkcdtmpdir {
      open("file", "w") {|f| f << "content" }
      begin
        File.symlink("file", "slnk")
      rescue NotImplementedError
        return
      end
      assert_raise(Errno::EMLINK, Errno::ELOOP) {
        open("slnk", File::RDONLY|File::NOFOLLOW) {}
      }
      assert_raise(Errno::EMLINK, Errno::ELOOP) {
        File.foreach("slnk", :open_args=>[File::RDONLY|File::NOFOLLOW]) {}
      }
    }
  end if /freebsd|linux/ =~ RUBY_PLATFORM and defined? File::NOFOLLOW

  def test_tainted
    make_tempfile {|t|
      assert_predicate(File.read(t.path, 4), :tainted?, '[ruby-dev:38826]')
      assert_predicate(File.open(t.path) {|f| f.read(4)}, :tainted?, '[ruby-dev:38826]')
    }
  end

  def test_binmode_after_closed
    make_tempfile {|t|
      assert_raise(IOError) {t.binmode}
    }
  end

  def test_DATA_binmode
    assert_separately([], <<-SRC)
assert_not_predicate(DATA, :binmode?)
__END__
    SRC
  end

  def test_threaded_flush
    bug3585 = '[ruby-core:31348]'
    src = "#{<<~"begin;"}\n#{<<~'end;'}"
    begin;
      t = Thread.new { sleep 3 }
      Thread.new {sleep 1; t.kill; p 'hi!'}
      t.join
    end;
    10.times.map do
      Thread.start do
        assert_in_out_err([], src, timeout: 20) {|stdout, stderr|
          assert_no_match(/hi.*hi/, stderr.join, bug3585)
        }
      end
    end.each {|th| th.join}
  end

  def test_flush_in_finalizer1
    bug3910 = '[ruby-dev:42341]'
    tmp = Tempfile.open("bug3910") {|t|
      path = t.path
      t.close
      fds = []
      assert_nothing_raised(TypeError, bug3910) do
        500.times {
          f = File.open(path, "w")
          f.instance_variable_set(:@test_flush_in_finalizer1, true)
          fds << f.fileno
          f.print "hoge"
        }
      end
      t
    }
  ensure
    ObjectSpace.each_object(File) {|f|
      if f.instance_variables.include?(:@test_flush_in_finalizer1)
        f.close
      end
    }
    tmp.close!
  end

  def test_flush_in_finalizer2
    bug3910 = '[ruby-dev:42341]'
    Tempfile.open("bug3910") {|t|
      path = t.path
      t.close
      begin
        1.times do
          io = open(path,"w")
          io.instance_variable_set(:@test_flush_in_finalizer2, true)
          io.print "hoge"
        end
        assert_nothing_raised(TypeError, bug3910) do
          GC.start
        end
      ensure
        ObjectSpace.each_object(File) {|f|
          if f.instance_variables.include?(:@test_flush_in_finalizer2)
            f.close
          end
        }
      end
      t.close!
    }
  end

  def test_readlines_limit_0
    bug4024 = '[ruby-dev:42538]'
    make_tempfile {|t|
      open(t.path, "r") do |io|
        assert_raise(ArgumentError, bug4024) do
          io.readlines(0)
        end
      end
    }
  end

  def test_each_line_limit_0
    bug4024 = '[ruby-dev:42538]'
    make_tempfile {|t|
      open(t.path, "r") do |io|
        assert_raise(ArgumentError, bug4024) do
          io.each_line(0).next
        end
      end
    }
  end

  def os_and_fs(path)
    uname = Etc.uname
    os = "#{uname[:sysname]} #{uname[:release]}"

    fs = nil
    if uname[:sysname] == 'Linux'
      # [ruby-dev:45703] Old Linux's fadvise() doesn't work on tmpfs.
      mount = `mount`
      mountpoints = []
      mount.scan(/ on (\S+) type (\S+) /) {
        mountpoints << [$1, $2]
      }
      mountpoints.sort_by {|mountpoint, fstype| mountpoint.length }.reverse_each {|mountpoint, fstype|
        if path == mountpoint
          fs = fstype
          break
        end
        mountpoint += "/" if %r{/\z} !~ mountpoint
        if path.start_with?(mountpoint)
          fs = fstype
          break
        end
      }
    end

    if fs
      "#{fs} on #{os}"
    else
      os
    end
  end

  def test_advise
    make_tempfile {|tf|
      assert_raise(ArgumentError, "no arguments") { tf.advise }
      %w{normal random sequential willneed dontneed noreuse}.map(&:to_sym).each do |adv|
        [[0,0], [0, 20], [400, 2]].each do |offset, len|
          open(tf.path) do |t|
            ret = assert_nothing_raised(lambda { os_and_fs(tf.path) }) {
              begin
                t.advise(adv, offset, len)
              rescue Errno::EINVAL => e
                if /linux/ =~ RUBY_PLATFORM && (Etc.uname[:release].split('.').map(&:to_i) <=> [3,6]) < 0
                  next # [ruby-core:65355] tmpfs is not supported
                else
                  raise e
                end
              end
            }
            assert_nil(ret)
            assert_raise(ArgumentError, "superfluous arguments") do
              t.advise(adv, offset, len, offset)
            end
            assert_raise(TypeError, "wrong type for first argument") do
              t.advise(adv.to_s, offset, len)
            end
            assert_raise(TypeError, "wrong type for last argument") do
              t.advise(adv, offset, Array(len))
            end
            assert_raise(RangeError, "last argument too big") do
              t.advise(adv, offset, 9999e99)
            end
          end
          assert_raise(IOError, "closed file") do
            make_tempfile {|tf2|
              tf2.advise(adv.to_sym, offset, len)
            }
          end
        end
      end
    }
  end

  def test_invalid_advise
    feature4204 = '[ruby-dev:42887]'
    make_tempfile {|tf|
      %W{Normal rand glark will_need zzzzzzzzzzzz \u2609}.map(&:to_sym).each do |adv|
        [[0,0], [0, 20], [400, 2]].each do |offset, len|
          open(tf.path) do |t|
            assert_raise_with_message(NotImplementedError, /#{Regexp.quote(adv.inspect)}/, feature4204) { t.advise(adv, offset, len) }
          end
        end
      end
    }
  end

  def test_fcntl_lock_linux
    pad = 0
    Tempfile.create(self.class.name) do |f|
      r, w = IO.pipe
      pid = fork do
        r.close
        lock = [Fcntl::F_WRLCK, IO::SEEK_SET, pad, 12, 34, 0].pack("s!s!i!L!L!i!")
        f.fcntl Fcntl::F_SETLKW, lock
        w.syswrite "."
        sleep
      end
      w.close
      assert_equal ".", r.read(1)
      r.close
      pad = 0
      getlock = [Fcntl::F_WRLCK, 0, pad, 0, 0, 0].pack("s!s!i!L!L!i!")
      f.fcntl Fcntl::F_GETLK, getlock

      ptype, whence, pad, start, len, lockpid = getlock.unpack("s!s!i!L!L!i!")

      assert_equal(ptype, Fcntl::F_WRLCK)
      assert_equal(whence, IO::SEEK_SET)
      assert_equal(start, 12)
      assert_equal(len, 34)
      assert_equal(pid, lockpid)

      Process.kill :TERM, pid
      Process.waitpid2(pid)
    end
  end if /x86_64-linux/ =~ RUBY_PLATFORM and # A binary form of struct flock depend on platform
    [nil].pack("p").bytesize == 8 # unless x32 platform.

  def test_fcntl_lock_freebsd
    start = 12
    len = 34
    sysid = 0
    Tempfile.create(self.class.name) do |f|
      r, w = IO.pipe
      pid = fork do
        r.close
        lock = [start, len, 0, Fcntl::F_WRLCK, IO::SEEK_SET, sysid].pack("qqis!s!i!")
        f.fcntl Fcntl::F_SETLKW, lock
        w.syswrite "."
        sleep
      end
      w.close
      assert_equal ".", r.read(1)
      r.close

      getlock = [0, 0, 0, Fcntl::F_WRLCK, 0, 0].pack("qqis!s!i!")
      f.fcntl Fcntl::F_GETLK, getlock

      start, len, lockpid, ptype, whence, sysid = getlock.unpack("qqis!s!i!")

      assert_equal(ptype, Fcntl::F_WRLCK)
      assert_equal(whence, IO::SEEK_SET)
      assert_equal(start, 12)
      assert_equal(len, 34)
      assert_equal(pid, lockpid)

      Process.kill :TERM, pid
      Process.waitpid2(pid)
    end
  end if /freebsd/ =~ RUBY_PLATFORM # A binary form of struct flock depend on platform

  def test_fcntl_dupfd
    Tempfile.create(self.class.name) do |f|
      fd = f.fcntl(Fcntl::F_DUPFD, 63)
      begin
        assert_operator(fd, :>=, 63)
      ensure
        IO.for_fd(fd).close
      end
    end
  end

  def test_cross_thread_close_fd
    with_pipe do |r,w|
      read_thread = Thread.new do
        begin
          r.read(1)
        rescue => e
          e
        end
      end

      sleep(0.1) until read_thread.stop?
      r.close
      read_thread.join
      assert_kind_of(IOError, read_thread.value)
    end
  end

  def test_cross_thread_close_stdio
    assert_separately([], <<-'end;')
      IO.pipe do |r,w|
        $stdin.reopen(r)
        r.close
        read_thread = Thread.new do
          begin
            $stdin.read(1)
          rescue IOError => e
            e
          end
        end
        sleep(0.1) until read_thread.stop?
        $stdin.close
        assert_kind_of(IOError, read_thread.value)
      end
    end;
  end

  def test_single_exception_on_close
    a = []
    t = []
    10.times do
      r, w = IO.pipe
      a << [r, w]
      t << Thread.new do
        while r.gets
        end rescue IOError
        Thread.current.pending_interrupt?
      end
    end
    a.each do |r, w|
      w.write(-"\n")
      w.close
      r.close
    end
    t.each do |th|
      assert_equal false, th.value, '[ruby-core:81581] [Bug #13632]'
    end
  end

  def test_open_mode
    feature4742 = "[ruby-core:36338]"
    bug6055 = '[ruby-dev:45268]'

    mkcdtmpdir do
      assert_not_nil(f = File.open('symbolic', 'w'))
      f.close
      assert_not_nil(f = File.open('numeric',  File::WRONLY|File::TRUNC|File::CREAT))
      f.close
      assert_not_nil(f = File.open('hash-symbolic', :mode => 'w'))
      f.close
      assert_not_nil(f = File.open('hash-numeric', :mode => File::WRONLY|File::TRUNC|File::CREAT), feature4742)
      f.close
      assert_nothing_raised(bug6055) {f = File.open('hash-symbolic', binmode: true)}
      f.close
    end
  end

  def test_s_write
    mkcdtmpdir do
      path = "test_s_write"
      File.write(path, "foo\nbar\nbaz")
      assert_equal("foo\nbar\nbaz", File.read(path))
      File.write(path, "FOO", 0)
      assert_equal("FOO\nbar\nbaz", File.read(path))
      File.write(path, "BAR")
      assert_equal("BAR", File.read(path))
      File.write(path, "\u{3042}", mode: "w", encoding: "EUC-JP")
      assert_equal("\u{3042}".encode("EUC-JP"), File.read(path, encoding: "EUC-JP"))
      File.delete path
      assert_equal(6, File.write(path, 'string', 2))
      File.delete path
      assert_raise(Errno::EINVAL) { File.write('nonexisting','string', -2) }
      assert_equal(6, File.write(path, 'string'))
      assert_equal(3, File.write(path, 'sub', 1))
      assert_equal("ssubng", File.read(path))
      File.delete path
      assert_equal(3, File.write(path, "foo", encoding: "UTF-8"))
      File.delete path
      assert_equal(3, File.write(path, "foo", 0, encoding: "UTF-8"))
      assert_equal("foo", File.read(path))
      assert_equal(1, File.write(path, "f", 1, encoding: "UTF-8"))
      assert_equal("ffo", File.read(path))
      File.delete path
      assert_equal(1, File.write(path, "f", 1, encoding: "UTF-8"))
      assert_equal("\00f", File.read(path))
      assert_equal(1, File.write(path, "f", 0, encoding: "UTF-8"))
      assert_equal("ff", File.read(path))
      assert_raise(TypeError) {
        File.write(path, "foo", Object.new => Object.new)
      }
    end
  end

  def test_s_binread_does_not_leak_with_invalid_offset
    assert_raise(Errno::EINVAL) { IO.binread(__FILE__, 0, -1) }
  end

  def test_s_binwrite
    mkcdtmpdir do
      path = "test_s_binwrite"
      File.binwrite(path, "foo\nbar\nbaz")
      assert_equal("foo\nbar\nbaz", File.read(path))
      File.binwrite(path, "FOO", 0)
      assert_equal("FOO\nbar\nbaz", File.read(path))
      File.binwrite(path, "BAR")
      assert_equal("BAR", File.read(path))
      File.binwrite(path, "\u{3042}")
      assert_equal("\u{3042}".force_encoding("ASCII-8BIT"), File.binread(path))
      File.delete path
      assert_equal(6, File.binwrite(path, 'string', 2))
      File.delete path
      assert_equal(6, File.binwrite(path, 'string'))
      assert_equal(3, File.binwrite(path, 'sub', 1))
      assert_equal("ssubng", File.binread(path))
      assert_equal(6, File.size(path))
      assert_raise(Errno::EINVAL) { File.binwrite('nonexisting', 'string', -2) }
      assert_nothing_raised(TypeError) { File.binwrite(path, "string", mode: "w", encoding: "EUC-JP") }
    end
  end

  def test_race_between_read
    Tempfile.create("test") {|file|
      begin
        path = file.path
        file.close
        write_file = File.open(path, "wt")
        read_file = File.open(path, "rt")

        threads = []
        10.times do |i|
          threads << Thread.new {write_file.print(i)}
          threads << Thread.new {read_file.read}
        end
        assert_join_threads(threads)
        assert(true, "[ruby-core:37197]")
      ensure
        read_file.close
        write_file.close
      end
    }
  end

  def test_warn
    assert_warning "warning\n" do
      warn "warning"
    end

    assert_warning '' do
      warn
    end

    assert_warning "[Feature #5029]\n[ruby-core:38070]\n" do
      warn "[Feature #5029]", "[ruby-core:38070]"
    end
  end

  def test_cloexec
    return unless defined? Fcntl::FD_CLOEXEC
    open(__FILE__) {|f|
      assert_predicate(f, :close_on_exec?)
      g = f.dup
      begin
        assert_predicate(g, :close_on_exec?)
        f.reopen(g)
        assert_predicate(f, :close_on_exec?)
      ensure
        g.close
      end
      g = IO.new(f.fcntl(Fcntl::F_DUPFD))
      begin
        assert_predicate(g, :close_on_exec?)
      ensure
        g.close
      end
    }
    IO.pipe {|r,w|
      assert_predicate(r, :close_on_exec?)
      assert_predicate(w, :close_on_exec?)
    }
  end

  def test_ioctl_linux
    # Alpha, mips, sparc and ppc have an another ioctl request number scheme.
    # So, hardcoded 0x80045200 may fail.
    assert_nothing_raised do
      File.open('/dev/urandom'){|f1|
        entropy_count = ""
        # RNDGETENTCNT(0x80045200) mean "get entropy count".
        f1.ioctl(0x80045200, entropy_count)
      }
    end

    buf = ''
    assert_nothing_raised do
      fionread = 0x541B
      File.open(__FILE__){|f1|
        f1.ioctl(fionread, buf)
      }
    end
    assert_equal(File.size(__FILE__), buf.unpack('i!')[0])
  end if /^(?:i.?86|x86_64)-linux/ =~ RUBY_PLATFORM

  def test_ioctl_linux2
    return unless STDIN.tty? # stdin is not a terminal
    begin
      f = File.open('/dev/tty')
    rescue Errno::ENOENT, Errno::ENXIO => e
      skip e.message
    else
      tiocgwinsz=0x5413
      winsize=""
      assert_nothing_raised {
        f.ioctl(tiocgwinsz, winsize)
      }
    ensure
      f&.close
    end
  end if /^(?:i.?86|x86_64)-linux/ =~ RUBY_PLATFORM

  def test_setpos
    mkcdtmpdir {
      File.open("tmp.txt", "wb") {|f|
        f.puts "a"
        f.puts "bc"
        f.puts "def"
      }
      pos1 = pos2 = pos3 = nil
      File.open("tmp.txt", "rb") {|f|
        assert_equal("a\n", f.gets)
        pos1 = f.pos
        assert_equal("bc\n", f.gets)
        pos2 = f.pos
        assert_equal("def\n", f.gets)
        pos3 = f.pos
        assert_equal(nil, f.gets)
      }
      File.open("tmp.txt", "rb") {|f|
        f.pos = pos1
        assert_equal("bc\n", f.gets)
        assert_equal("def\n", f.gets)
        assert_equal(nil, f.gets)
      }
      File.open("tmp.txt", "rb") {|f|
        f.pos = pos2
        assert_equal("def\n", f.gets)
        assert_equal(nil, f.gets)
      }
      File.open("tmp.txt", "rb") {|f|
        f.pos = pos3
        assert_equal(nil, f.gets)
      }
      File.open("tmp.txt", "rb") {|f|
        f.pos = File.size("tmp.txt")
        s = "not empty string        "
        assert_equal("", f.read(0,s))
      }
    }
  end

  def test_std_fileno
    assert_equal(0, STDIN.fileno)
    assert_equal(1, STDOUT.fileno)
    assert_equal(2, STDERR.fileno)
    assert_equal(0, $stdin.fileno)
    assert_equal(1, $stdout.fileno)
    assert_equal(2, $stderr.fileno)
  end

  def test_frozen_fileno
    bug9865 = '[ruby-dev:48241] [Bug #9865]'
    with_pipe do |r,w|
      fd = r.fileno
      assert_equal(fd, r.freeze.fileno, bug9865)
    end
  end

  def test_frozen_autoclose
    with_pipe do |r,w|
      assert_equal(true, r.freeze.autoclose?)
    end
  end

  def test_sysread_locktmp
    bug6099 = '[ruby-dev:45297]'
    buf = " " * 100
    data = "a" * 100
    with_pipe do |r,w|
      th = Thread.new {r.sysread(100, buf)}
      Thread.pass until th.stop?
      buf.replace("")
      assert_empty(buf, bug6099)
      w.write(data)
      Thread.pass while th.alive?
      th.join
    end
    assert_equal(data, buf, bug6099)
  end

  def test_readpartial_locktmp
    bug6099 = '[ruby-dev:45297]'
    buf = " " * 100
    data = "a" * 100
    th = nil
    with_pipe do |r,w|
      r.nonblock = true
      th = Thread.new {r.readpartial(100, buf)}

      Thread.pass until th.stop?

      assert_equal 100, buf.bytesize

      msg = /can't modify string; temporarily locked/
      assert_raise_with_message(RuntimeError, msg) do
        buf.replace("")
      end
      assert_predicate(th, :alive?)
      w.write(data)
      th.join
    end
    assert_equal(data, buf, bug6099)
  end

  def test_advise_pipe
    # we don't know if other platforms have a real posix_fadvise()
    with_pipe do |r,w|
      # Linux 2.6.15 and earlier returned EINVAL instead of ESPIPE
      assert_raise(Errno::ESPIPE, Errno::EINVAL) {
        r.advise(:willneed) or skip "fadvise(2) is not implemented"
      }
      assert_raise(Errno::ESPIPE, Errno::EINVAL) {
        w.advise(:willneed) or skip "fadvise(2) is not implemented"
      }
    end
  end if /linux/ =~ RUBY_PLATFORM

  def assert_buffer_not_raise_shared_string_error
    bug6764 = '[ruby-core:46586]'
    bug9847 = '[ruby-core:62643] [Bug #9847]'
    size = 28
    data = [*"a".."z", *"A".."Z"].shuffle.join("")
    t = Tempfile.new("test_io")
    t.write(data)
    t.close
    w = []
    assert_nothing_raised(RuntimeError, bug6764) do
      buf = ''
      File.open(t.path, "r") do |r|
        while yield(r, size, buf)
          w << buf.dup
        end
      end
    end
    assert_equal(data, w.join(""), bug9847)
  ensure
    t.close!
  end

  def test_read_buffer_not_raise_shared_string_error
    assert_buffer_not_raise_shared_string_error do |r, size, buf|
      r.read(size, buf)
    end
  end

  def test_sysread_buffer_not_raise_shared_string_error
    assert_buffer_not_raise_shared_string_error do |r, size, buf|
      begin
        r.sysread(size, buf)
      rescue EOFError
        nil
      end
    end
  end

  def test_readpartial_buffer_not_raise_shared_string_error
    assert_buffer_not_raise_shared_string_error do |r, size, buf|
      begin
        r.readpartial(size, buf)
      rescue EOFError
        nil
      end
    end
  end

  def test_puts_recursive_ary
    bug5986 = '[ruby-core:42444]'
    c = Class.new {
      def to_ary
        [self]
      end
    }
    s = StringIO.new
    s.puts(c.new)
    assert_equal("[...]\n", s.string, bug5986)
  end

  def test_io_select_with_many_files
    bug8080 = '[ruby-core:53349]'

    assert_normal_exit %q{
      require "tempfile"

      # Unfortunately, ruby doesn't export FD_SETSIZE. then we assume it's 1024.
      fd_setsize = 1024

      # try to raise RLIM_NOFILE to >FD_SETSIZE
      begin
        Process.setrlimit(Process::RLIMIT_NOFILE, fd_setsize+20)
      rescue Errno::EPERM
        exit 0
      end

      tempfiles = []
      (0..fd_setsize+1).map {|i|
        tempfiles << Tempfile.open("test_io_select_with_many_files")
      }

      IO.select(tempfiles)
    }, bug8080, timeout: 100
  end if defined?(Process::RLIMIT_NOFILE)

  def test_read_32bit_boundary
    bug8431 = '[ruby-core:55098] [Bug #8431]'
    make_tempfile {|t|
      assert_separately(["-", bug8431, t.path], <<-"end;")
        msg = ARGV.shift
        f = open(ARGV[0], "rb")
        f.seek(0xffff_ffff)
        assert_nil(f.read(1), msg)
      end;
    }
  end if /mswin|mingw/ =~ RUBY_PLATFORM

  def test_write_32bit_boundary
    bug8431 = '[ruby-core:55098] [Bug #8431]'
    make_tempfile {|t|
      def t.close(unlink_now = false)
        # TODO: Tempfile should deal with this delay on Windows?
        # NOTE: re-opening with O_TEMPORARY does not work.
        path = self.path
        ret = super
        if unlink_now
          begin
            File.unlink(path)
          rescue Errno::ENOENT
          rescue Errno::EACCES
            sleep(2)
            retry
          end
        end
        ret
      end

      begin
        assert_separately(["-", bug8431, t.path], <<-"end;", timeout: 30)
          msg = ARGV.shift
          f = open(ARGV[0], "wb")
          f.seek(0xffff_ffff)
          begin
            # this will consume very long time or fail by ENOSPC on a
            # filesystem which sparse file is not supported
            f.write('1')
            pos = f.tell
          rescue Errno::ENOSPC
            skip "non-sparse file system"
          rescue SystemCallError
          else
            assert_equal(0x1_0000_0000, pos, msg)
          end
        end;
      rescue Timeout::Error
        skip "Timeout because of slow file writing"
      end
    }
  end if /mswin|mingw/ =~ RUBY_PLATFORM

  def test_read_unlocktmp_ensure
    bug8669 = '[ruby-core:56121] [Bug #8669]'

    str = ""
    IO.pipe {|r,|
      t = Thread.new {
        assert_raise(RuntimeError) {
          r.read(nil, str)
        }
      }
      sleep 0.1 until t.stop?
      t.raise
      sleep 0.1 while t.alive?
      assert_nothing_raised(RuntimeError, bug8669) { str.clear }
      t.join
    }
  end if /cygwin/ !~ RUBY_PLATFORM

  def test_readpartial_unlocktmp_ensure
    bug8669 = '[ruby-core:56121] [Bug #8669]'

    str = ""
    IO.pipe {|r, w|
      t = Thread.new {
        assert_raise(RuntimeError) {
          r.readpartial(4096, str)
        }
      }
      sleep 0.1 until t.stop?
      t.raise
      sleep 0.1 while t.alive?
      assert_nothing_raised(RuntimeError, bug8669) { str.clear }
      t.join
    }
  end if /cygwin/ !~ RUBY_PLATFORM

  def test_readpartial_bad_args
    IO.pipe do |r, w|
      w.write '.'
      buf = String.new
      assert_raise(ArgumentError) { r.readpartial(1, buf, exception: false) }
      assert_raise(TypeError) { r.readpartial(1, exception: false) }
      assert_equal [[r],[],[]], IO.select([r], nil, nil, 1)
      assert_equal '.', r.readpartial(1)
    end
  end

  def test_sysread_unlocktmp_ensure
    bug8669 = '[ruby-core:56121] [Bug #8669]'

    str = ""
    IO.pipe {|r, w|
      t = Thread.new {
        assert_raise(RuntimeError) {
          r.sysread(4096, str)
        }
      }
      sleep 0.1 until t.stop?
      t.raise
      sleep 0.1 while t.alive?
      assert_nothing_raised(RuntimeError, bug8669) { str.clear }
      t.join
    }
  end if /cygwin/ !~ RUBY_PLATFORM

  def test_exception_at_close
    bug10153 = '[ruby-core:64463] [Bug #10153] exception in close at the end of block'
    assert_raise(Errno::EBADF, bug10153) do
      IO.pipe do |r, w|
        assert_nothing_raised {IO.open(w.fileno) {}}
      end
    end
  end

  def test_close_twice
    open(__FILE__) {|f|
      assert_equal(nil, f.close)
      assert_equal(nil, f.close)
    }
  end

  def test_close_uninitialized
    io = IO.allocate
    assert_raise(IOError) { io.close }
  end

  def test_open_fifo_does_not_block_other_threads
    mkcdtmpdir {
      File.mkfifo("fifo")
      assert_separately([], <<-'EOS')
        t1 = Thread.new {
          open("fifo", "r") {|r|
            r.read
          }
        }
        t2 = Thread.new {
          open("fifo", "w") {|w|
            w.write "foo"
          }
        }
        t1_value, _ = assert_join_threads([t1, t2])
        assert_equal("foo", t1_value)
      EOS
    }
  end if /mswin|mingw|bccwin|cygwin/ !~ RUBY_PLATFORM

  def test_open_flag
    make_tempfile do |t|
      assert_raise(Errno::EEXIST){ open(t.path, File::WRONLY|File::CREAT, flags: File::EXCL){} }
      assert_raise(Errno::EEXIST){ open(t.path, 'w', flags: File::EXCL){} }
      assert_raise(Errno::EEXIST){ open(t.path, mode: 'w', flags: File::EXCL){} }
    end
  end

  def test_open_flag_binary
    make_tempfile do |t|
      open(t.path, File::RDONLY, flags: File::BINARY) do |f|
        assert_equal true, f.binmode?
      end
      open(t.path, 'r', flags: File::BINARY) do |f|
        assert_equal true, f.binmode?
      end
      open(t.path, mode: 'r', flags: File::BINARY) do |f|
        assert_equal true, f.binmode?
      end
    end
  end if File::BINARY != 0

  def test_exclusive_mode
    make_tempfile do |t|
      assert_raise(Errno::EEXIST){ open(t.path, 'wx'){} }
      assert_raise(ArgumentError){ open(t.path, 'rx'){} }
      assert_raise(ArgumentError){ open(t.path, 'ax'){} }
    end
  end

  def test_race_gets_and_close
    opt = { signal: :ABRT, timeout: 200 }
    assert_separately([], "#{<<-"begin;"}\n#{<<-"end;"}", opt)
    bug13076 = '[ruby-core:78845] [Bug #13076]'
    begin;
      10.times do |i|
        a = []
        t = []
        10.times do
          r,w = IO.pipe
          a << [r,w]
          t << Thread.new do
            begin
              while r.gets
              end
            rescue IOError
            end
          end
        end
        a.each do |r,w|
          w.puts "hoge"
          w.close
          r.close
        end
        t.each do |th|
          assert_same(th, th.join(2), bug13076)
        end
      end
    end;
  end

  def test_race_closed_stream
    assert_separately([], "#{<<-"begin;"}\n#{<<-"end;"}")
    begin;
      bug13158 = '[ruby-core:79262] [Bug #13158]'
      closed = nil
      q = Queue.new
      IO.pipe do |r, w|
        thread = Thread.new do
          begin
            q << true
            assert_raise_with_message(IOError, /stream closed/) do
              while r.gets
              end
            end
          ensure
            closed = r.closed?
          end
        end
        q.pop
        sleep 0.01 until thread.stop?
        r.close
        thread.join
        assert_equal(true, closed, bug13158 + ': stream should be closed')
      end
    end;
  end

  if RUBY_ENGINE == "ruby" # implementation details
    def test_foreach_rs_conversion
      make_tempfile {|t|
        a = []
        rs = Struct.new(:count).new(0)
        def rs.to_str; self.count += 1; "\n"; end
        IO.foreach(t.path, rs) {|x| a << x }
        assert_equal(["foo\n", "bar\n", "baz\n"], a)
        assert_equal(1, rs.count)
      }
    end

    def test_foreach_rs_invalid
      make_tempfile {|t|
        rs = Object.new
        def rs.to_str; raise "invalid rs"; end
        assert_raise(RuntimeError) do
          IO.foreach(t.path, rs, mode:"w") {}
        end
        assert_equal(["foo\n", "bar\n", "baz\n"], IO.foreach(t.path).to_a)
      }
    end

    def test_foreach_limit_conversion
      make_tempfile {|t|
        a = []
        lim = Struct.new(:count).new(0)
        def lim.to_int; self.count += 1; -1; end
        IO.foreach(t.path, lim) {|x| a << x }
        assert_equal(["foo\n", "bar\n", "baz\n"], a)
        assert_equal(1, lim.count)
      }
    end

    def test_foreach_limit_invalid
      make_tempfile {|t|
        lim = Object.new
        def lim.to_int; raise "invalid limit"; end
        assert_raise(RuntimeError) do
          IO.foreach(t.path, lim, mode:"w") {}
        end
        assert_equal(["foo\n", "bar\n", "baz\n"], IO.foreach(t.path).to_a)
      }
    end

    def test_readlines_rs_invalid
      make_tempfile {|t|
        rs = Object.new
        def rs.to_str; raise "invalid rs"; end
        assert_raise(RuntimeError) do
          IO.readlines(t.path, rs, mode:"w")
        end
        assert_equal(["foo\n", "bar\n", "baz\n"], IO.readlines(t.path))
      }
    end

    def test_readlines_limit_invalid
      make_tempfile {|t|
        lim = Object.new
        def lim.to_int; raise "invalid limit"; end
        assert_raise(RuntimeError) do
          IO.readlines(t.path, lim, mode:"w")
        end
        assert_equal(["foo\n", "bar\n", "baz\n"], IO.readlines(t.path))
      }
    end

    def test_closed_stream_in_rescue
      assert_separately([], "#{<<-"begin;"}\n#{<<~"end;"}")
      begin;
      10.times do
        assert_nothing_raised(RuntimeError, /frozen IOError/) do
          IO.pipe do |r, w|
            th = Thread.start {r.close}
            r.gets
          rescue IOError
            # swallow pending exceptions
            begin
              sleep 0.001
            rescue IOError
              retry
            end
          ensure
            th.kill.join
          end
        end
      end
      end;
    end

    def test_write_no_garbage
      skip "multiple threads already active" if Thread.list.size > 1
      res = {}
      ObjectSpace.count_objects(res) # creates strings on first call
      [ 'foo'.b, '*' * 24 ].each do |buf|
        with_pipe do |r, w|
          GC.disable
          begin
            before = ObjectSpace.count_objects(res)[:T_STRING]
            n = w.write(buf)
            s = w.syswrite(buf)
            after = ObjectSpace.count_objects(res)[:T_STRING]
          ensure
            GC.enable
          end
          assert_equal before, after,
            "no strings left over after write [ruby-core:78898] [Bug #13085]: #{ before } strings before write -> #{ after } strings after write"
          assert_not_predicate buf, :frozen?, 'no inadvertent freeze'
          assert_equal buf.bytesize, n, 'IO#write wrote expected size'
          assert_equal s, n, 'IO#syswrite wrote expected size'
        end
      end
    end

    def test_pread
      make_tempfile { |t|
        open(t.path) do |f|
          assert_equal("bar", f.pread(3, 4))
          buf = "asdf"
          assert_equal("bar", f.pread(3, 4, buf))
          assert_equal("bar", buf)
          assert_raise(EOFError) { f.pread(1, f.size) }
        end
      }
    end if IO.method_defined?(:pread)

    def test_pwrite
      make_tempfile { |t|
        open(t.path, IO::RDWR) do |f|
          assert_equal(3, f.pwrite("ooo", 4))
          assert_equal("ooo", f.pread(3, 4))
        end
      }
    end if IO.method_defined?(:pread) and IO.method_defined?(:pwrite)
  end

  def test_select_exceptfds
    if Etc.uname[:sysname] == 'SunOS' && Etc.uname[:release] == '5.11'
      skip "Solaris 11 fails this"
    end

    TCPServer.open('localhost', 0) do |svr|
      con = TCPSocket.new('localhost', svr.addr[1])
      acc = svr.accept
      assert_equal 5, con.send('hello', Socket::MSG_OOB)
      set = IO.select(nil, nil, [acc], 30)
      assert_equal([[], [], [acc]], set, 'IO#select exceptions array OK')
      acc.close
      con.close
    end
  end if Socket.const_defined?(:MSG_OOB)

  def test_recycled_fd_close
    dot = -'.'
    IO.pipe do |sig_rd, sig_wr|
      noex = Thread.new do # everything right and never see exceptions :)
        until sig_rd.wait_readable(0)
          IO.pipe do |r, w|
            th = Thread.new { r.read(1) }
            w.write(dot)

            assert_same th, th.join(15), '"good" reader timeout'
            assert_equal(dot, th.value)
          end
        end
        sig_rd.read(4)
      end
      1000.times do |i| # stupid things and make exceptions:
        IO.pipe do |r,w|
          th = Thread.new do
            begin
              while r.gets
              end
            rescue IOError => e
              e
            end
          end
          Thread.pass until th.stop?

          r.close
          assert_same th, th.join(30), '"bad" reader timeout'
          assert_match(/stream closed/, th.value.message)
        end
      end
      sig_wr.write 'done'
      assert_same noex, noex.join(20), '"good" writer timeout'
      assert_equal 'done', noex.value ,'r63216'
    end
  end

  def test_select_leak
    # avoid malloc arena explosion from glibc and jemalloc:
    env = {
      'MALLOC_ARENA_MAX' => '1',
      'MALLOC_ARENA_TEST' => '1',
      'MALLOC_CONF' => 'narenas:1',
    }
    assert_no_memory_leak([env], <<-"end;", <<-"end;", rss: true, timeout: 60)
      r, w = IO.pipe
      rset = [r]
      wset = [w]
      exc = StandardError.new(-"select used to leak on exception")
      exc.set_backtrace([])
      Thread.new { IO.select(rset, wset, nil, 0) }.join
    end;
      th = Thread.new do
        Thread.handle_interrupt(StandardError => :on_blocking) do
          begin
            IO.select(rset, wset)
          rescue
            retry
          end while true
        end
      end
      50_000.times do
        Thread.pass until th.stop?
        th.raise(exc)
      end
      th.kill
      th.join
    end;
  end

  def test_external_encoding_index
    IO.pipe {|r, w|
      assert_raise(TypeError) {Marshal.dump(r)}
      assert_raise(TypeError) {Marshal.dump(w)}
    }
  end
end