class FakeFS::Dir

def self.mktmpdir(prefix_suffix = nil, tmpdir = nil)
  case prefix_suffix
  when nil
    prefix = 'd'
    suffix = ''
  when String
    prefix = prefix_suffix
    suffix = ''
  when Array
    prefix = prefix_suffix[0]
    suffix = prefix_suffix[1]
  else
    raise ArgumentError, "unexpected prefix_suffix: #{prefix_suffix.inspect}"
  end
  t = Time.now.strftime('%Y%m%d')
  n = nil
  begin
    path = "#{tmpdir}/#{prefix}#{t}-#{$$}-#{rand(0x100000000).to_s(36)}"
    path << "-#{n}" if n
    path << suffix
    mkdir(path, 0o700)
  rescue Errno::EEXIST
    n ||= 0
    n += 1
    retry
  end
  if block_given?
    begin
      yield path
    ensure
      require 'fileutils'
      # This here was using FileUtils.remove_entry_secure instead of just
      # .rm_r. However, the security concerns that apply to
      # .rm_r/.remove_entry_secure shouldn't apply to a test fake
      # filesystem. :^)
      FileUtils.rm_r path
    end
  else
    path
  end
end