module ActiveSupport::Testing::Isolation::Forking

def run_in_isolation(&blk)
  read, write = IO.pipe
  read.binmode
  write.binmode
  pid = fork do
    read.close
    yield
    write.puts [Marshal.dump(self.dup)].pack("m")
    exit!
  end
  write.close
  result = read.read
  Process.wait2(pid)
  return result.unpack("m")[0]
end