/test/ruby/test_io.rb

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# 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
          reader0, writer0 = IO.pipe
          reader0.binmode
          writer0.binmode

          reader1, writer1 = IO.pipe

          reader2, writer2 = IO.pipe(binmode: true)
          assert_predicate writer0, :binmode?
          assert_predicate writer2, :binmode?
          assert_equal writer0.binmode?, writer2.binmode?
          assert_equal writer0.external_encoding, writer2.external_encoding
          assert_equal writer0.internal_encoding, writer2.internal_encoding
          assert_predicate reader0, :binmode?
          assert_predicate reader2, :binmode?
          assert_equal reader0.binmode?, reader2.binmode?
          assert_equal reader0.external_encoding, reader2.external_encoding
          assert_equal reader0.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
          [
            reader0, writer0,
            reader1, writer1,
            reader2, writer2,
            reader3, writer3,
            reader4, writer4,
            reader5, writer5,
          ].compact.map(&:close)
        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_dat…