diff --git a/ChangeLog b/ChangeLog
index fbba2c1a97..8f43e39b00 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+Mon Sep 19 05:58:59 2005  Minero Aoki  <aamine@loveruby.net>
+
+	* lib/fileutils.rb: use module_function instead of single extend.
+
+	* test/fileutils/test_fileutils.rb: test existence of singleton
+	  methods.
+
 Mon Sep 19 05:32:41 2005  Minero Aoki  <aamine@loveruby.net>
 
 	* lib/fileutils.rb (remove_entry_secure): does not use chdir(2).
diff --git a/lib/fileutils.rb b/lib/fileutils.rb
index e3fbabce0c..3171886b0c 100644
--- a/lib/fileutils.rb
+++ b/lib/fileutils.rb
@@ -84,7 +84,10 @@
 
 module FileUtils
 
-  # All methods are module_function.
+  def self.private_module_function(name)   #:nodoc:
+    module_function name
+    private_class_method name
+  end
 
   # This hash table holds command options.
   OPT_TABLE = {}   #:nodoc: internal use only
@@ -97,8 +100,10 @@ module FileUtils
   def pwd
     Dir.pwd
   end
+  module_function :pwd
 
   alias getwd pwd
+  module_function :getwd
 
   #
   # Options: verbose
@@ -116,8 +121,10 @@ module FileUtils
     Dir.chdir(dir, &block) unless options[:noop]
     fu_output_message 'cd -' if options[:verbose] and block
   end
+  module_function :cd
 
   alias chdir cd
+  module_function :chdir
 
   OPT_TABLE['cd']    =
   OPT_TABLE['chdir'] = %w( verbose )
@@ -143,6 +150,7 @@ module FileUtils
     end
     true
   end
+  module_function :uptodate?
 
   #
   # Options: mode noop verbose
@@ -164,6 +172,7 @@ module FileUtils
       fu_mkdir dir, options[:mode]
     end
   end
+  module_function :mkdir
 
   OPT_TABLE['mkdir'] = %w( noop verbose mode )
 
@@ -214,15 +223,18 @@ module FileUtils
 
     return *list
   end
+  module_function :mkdir_p
 
   alias mkpath    mkdir_p
   alias makedirs  mkdir_p
+  module_function :mkpath
+  module_function :makedirs
 
   OPT_TABLE['mkdir_p']  =
   OPT_TABLE['mkpath']   =
   OPT_TABLE['makedirs'] = %w( noop verbose )
 
-  def fu_mkdir(path, mode)
+  def fu_mkdir(path, mode)   #:nodoc:
     path = path.sub(%r</\z>, '')
     if mode
       Dir.mkdir path, mode
@@ -231,7 +243,7 @@ module FileUtils
       Dir.mkdir path
     end
   end
-  private :fu_mkdir
+  private_module_function :fu_mkdir
 
   #
   # Options: noop, verbose
@@ -252,6 +264,7 @@ module FileUtils
       Dir.rmdir dir.sub(%r</\z>, '')
     end
   end
+  module_function :rmdir
 
   OPT_TABLE['rmdir'] = %w( noop verbose )
 
@@ -286,8 +299,10 @@ module FileUtils
       File.link s, d
     end
   end
+  module_function :ln
 
   alias link ln
+  module_function :link
 
   OPT_TABLE['ln']   =
   OPT_TABLE['link'] = %w( noop verbose force )
@@ -323,8 +338,10 @@ module FileUtils
       File.symlink s, d
     end
   end
+  module_function :ln_s
 
   alias symlink ln_s
+  module_function :symlink
 
   OPT_TABLE['ln_s']    =
   OPT_TABLE['symlink'] = %w( noop verbose force )
@@ -341,6 +358,7 @@ module FileUtils
     options[:force] = true
     ln_s src, dest, options
   end
+  module_function :ln_sf
 
   OPT_TABLE['ln_sf'] = %w( noop verbose )
 
@@ -365,8 +383,10 @@ module FileUtils
       copy_file s, d, options[:preserve]
     end
   end
+  module_function :cp
 
   alias copy cp
+  module_function :copy
 
   OPT_TABLE['cp']   =
   OPT_TABLE['copy'] = %w( noop verbose preserve )
@@ -402,6 +422,7 @@ module FileUtils
       copy_entry s, d, options[:preserve], options[:dereference_root]
     end
   end
+  module_function :cp_r
 
   OPT_TABLE['cp_r'] = %w( noop verbose preserve dereference_root )
 
@@ -426,6 +447,7 @@ module FileUtils
       ent.copy_metadata destent.path if preserve
     end
   end
+  module_function :copy_entry
 
   #
   # Copies file contents of +src+ to +dest+.
@@ -436,6 +458,7 @@ module FileUtils
     ent.copy_file dest
     ent.copy_metadata dest if preserve
   end
+  module_function :copy_file
 
   #
   # Copies stream +src+ to +dest+.
@@ -445,6 +468,7 @@ module FileUtils
   def copy_stream(src, dest)
     fu_copy_stream0 src, dest, fu_stream_blksize(src, dest)
   end
+  module_function :copy_stream
 
   #
   # Options: force noop verbose
@@ -482,8 +506,10 @@ module FileUtils
       end
     end
   end
+  module_function :mv
 
   alias move mv
+  module_function :move
 
   OPT_TABLE['mv']   =
   OPT_TABLE['move'] = %w( noop verbose force )
@@ -491,7 +517,7 @@ module FileUtils
   def rename_cannot_overwrite_file?   #:nodoc:
     /djgpp|cygwin|mswin|mingw|bccwin|wince|emx/ =~ RUBY_PLATFORM
   end
-  private :rename_cannot_overwrite_file?
+  private_module_function :rename_cannot_overwrite_file?
 
   #
   # Options: force noop verbose
@@ -513,8 +539,10 @@ module FileUtils
       remove_file path, options[:force]
     end
   end
+  module_function :rm
 
   alias remove rm
+  module_function :remove
 
   OPT_TABLE['rm']     =
   OPT_TABLE['remove'] = %w( noop verbose force )
@@ -532,8 +560,10 @@ module FileUtils
     options[:force] = true
     rm list, options
   end
+  module_function :rm_f
 
   alias safe_unlink rm_f
+  module_function :safe_unlink
 
   OPT_TABLE['rm_f']        =
   OPT_TABLE['safe_unlink'] = %w( noop verbose )
@@ -573,6 +603,7 @@ module FileUtils
       end
     end
   end
+  module_function :rm_r
 
   OPT_TABLE['rm_r'] = %w( noop verbose force secure )
 
@@ -592,8 +623,10 @@ module FileUtils
     options[:force] = true
     rm_r list, options
   end
+  module_function :rm_rf
 
   alias rmtree rm_rf
+  module_function :rmtree
 
   OPT_TABLE['rm_rf']  =
   OPT_TABLE['rmtree'] = %w( noop verbose secure )
@@ -679,19 +712,21 @@ module FileUtils
   rescue
     raise unless force
   end
+  module_function :remove_entry_secure
 
-  def fu_have_symlink?
+  def fu_have_symlink?   #:nodoc
     File.symlink nil, nil
   rescue NotImplementedError
     return false
   rescue
     return true
   end
+  private_module_function :fu_have_symlink?
 
-  def fu_stat_identical_entry?(a, b)
+  def fu_stat_identical_entry?(a, b)   #:nodoc:
     a.dev == b.dev and a.ino == b.ino
   end
-  private :fu_stat_identical_entry?
+  private_module_function :fu_stat_identical_entry?
 
   #
   # This method removes a file system entry +path+.
@@ -711,6 +746,7 @@ module FileUtils
   rescue
     raise unless force
   end
+  module_function :remove_entry
 
   #
   # Removes a file +path+.
@@ -721,6 +757,7 @@ module FileUtils
   rescue
     raise unless force
   end
+  module_function :remove_file
 
   #
   # Removes a directory +dir+ and its contents recursively.
@@ -729,6 +766,7 @@ module FileUtils
   def remove_dir(path, force = false)
     remove_entry path, force   # FIXME?? check if it is a directory
   end
+  module_function :remove_dir
 
   #
   # Returns true if the contents of a file A and a file B are identical.
@@ -744,9 +782,12 @@ module FileUtils
       }
     }
   end
+  module_function :compare_file
 
   alias identical? compare_file
   alias cmp compare_file
+  module_function :identical?
+  module_function :cmp
 
   #
   # Returns true if the contents of a stream +a+ and +b+ are identical.
@@ -765,6 +806,7 @@ module FileUtils
     end
     false
   end
+  module_function :compare_stream
 
   #
   # Options: mode noop verbose
@@ -789,6 +831,7 @@ module FileUtils
       end
     end
   end
+  module_function :install
 
   OPT_TABLE['install'] = %w( noop verbose preserve mode )
 
@@ -811,6 +854,7 @@ module FileUtils
       Entry_.new(path).chmod mode
     end
   end
+  module_function :chmod
 
   OPT_TABLE['chmod'] = %w( noop verbose )
 
@@ -839,6 +883,7 @@ module FileUtils
       end
     end
   end
+  module_function :chmod_R
 
   OPT_TABLE['chmod_R'] = %w( noop verbose )
 
@@ -867,6 +912,7 @@ module FileUtils
       Entry_.new(path).chown uid, gid
     end
   end
+  module_function :chown
 
   OPT_TABLE['chown'] = %w( noop verbose )
 
@@ -903,6 +949,7 @@ module FileUtils
       end
     end
   end
+  module_function :chown_R
 
   OPT_TABLE['chown_R'] = %w( noop verbose )
 
@@ -917,7 +964,7 @@ module FileUtils
       else Etc.getpwnam(user).uid
       end
     end
-    private :fu_get_uid
+    private_module_function :fu_get_uid
 
     def fu_get_gid(group)   #:nodoc:
       return nil unless group
@@ -926,7 +973,7 @@ module FileUtils
       else Etc.getgrnam(group).gid
       end
     end
-    private :fu_get_gid
+    private_module_function :fu_get_gid
 
   rescue LoadError
     # need Win32 support???
@@ -934,10 +981,12 @@ module FileUtils
     def fu_get_uid(user)   #:nodoc:
       user    # FIXME
     end
+    private_module_function :fu_get_uid
 
     def fu_get_gid(group)   #:nodoc:
       group   # FIXME
     end
+    private_module_function :fu_get_gid
   end
 
   #
@@ -965,6 +1014,7 @@ module FileUtils
       end
     end
   end
+  module_function :touch
 
   OPT_TABLE['touch'] = %w( noop verbose )
 
@@ -1006,6 +1056,7 @@ module FileUtils
   end
 
   include StreamUtils_
+  extend StreamUtils_
 
   class Entry_   #:nodoc: internal use only
     include StreamUtils_
@@ -1310,18 +1361,20 @@ module FileUtils
     end
   end   # class Entry_
 
-  def fu_list(arg)
+  def fu_list(arg)   #:nodoc:
     [arg].flatten.map {|path| File.path(path) }
   end
+  private_module_function :fu_list
 
-  def fu_each_src_dest(src, dest)
+  def fu_each_src_dest(src, dest)   #:nodoc:
     fu_each_src_dest0(src, dest) do |s, d|
       raise ArgumentError, "same file: #{s} and #{d}" if fu_same?(s, d)
       yield s, d
     end
   end
+  private_module_function :fu_each_src_dest
 
-  def fu_each_src_dest0(src, dest)
+  def fu_each_src_dest0(src, dest)   #:nodoc:
     if src.is_a?(Array)
       src.each do |s|
         s = File.path(s)
@@ -1336,8 +1389,9 @@ module FileUtils
       end
     end
   end
+  private_module_function :fu_each_src_dest0
 
-  def fu_same?(a, b)
+  def fu_same?(a, b)   #:nodoc:
     if fu_have_st_ino?
       st1 = File.stat(a)
       st2 = File.stat(b)
@@ -1348,20 +1402,23 @@ module FileUtils
   rescue Errno::ENOENT
     return false
   end
+  private_module_function :fu_same?
 
-  def fu_have_st_ino?
+  def fu_have_st_ino?   #:nodoc:
     not fu_windows?
   end
+  private_module_function :fu_have_st_ino?
 
-  def fu_check_options(options, *optdecl)
+  def fu_check_options(options, *optdecl)   #:nodoc:
     h = options.dup
     optdecl.each do |name|
       h.delete name
     end
     raise ArgumentError, "no such option: #{h.keys.join(' ')}" unless h.empty?
   end
+  private_module_function :fu_check_options
 
-  def fu_update_option(args, new)
+  def fu_update_option(args, new)   #:nodoc:
     if args.last.is_a?(Hash)
       args[-1] = args.last.dup.update(new)
     else
@@ -1369,18 +1426,17 @@ module FileUtils
     end
     args
   end
+  private_module_function :fu_update_option
 
   @fileutils_output = $stderr
   @fileutils_label  = ''
 
-  def fu_output_message(msg)
+  def fu_output_message(msg)   #:nodoc:
     @fileutils_output ||= $stderr
     @fileutils_label  ||= ''
     @fileutils_output.puts @fileutils_label + msg
   end
-
-  # All Methods are public instance method and are public class method.
-  extend self
+  private_module_function :fu_output_message
 
   #
   # Returns an Array of method names which have any options.
diff --git a/test/fileutils/test_fileutils.rb b/test/fileutils/test_fileutils.rb
index f2f8683233..2cce67cc2f 100644
--- a/test/fileutils/test_fileutils.rb
+++ b/test/fileutils/test_fileutils.rb
@@ -76,6 +76,10 @@ class TestFileUtils
 
   include FileUtils
 
+  def check_singleton(name)
+    assert_equal true, ::FileUtils.public_methods.include?(name.to_s)
+  end
+
   def my_rm_rf(path)
     if File.exist?('/bin/rm')
       system %Q[/bin/rm -rf "#{path}"]
@@ -164,6 +168,8 @@ class TestFileUtils
   #
 
   def test_pwd
+    check_singleton :pwd
+
     assert_equal Dir.pwd, pwd()
 
     cwd = Dir.pwd
@@ -181,6 +187,8 @@ end
   end
 
   def test_cmp
+    check_singleton :cmp
+
     TARGETS.each do |fname|
       assert cmp(fname, fname), 'not same?'
     end
@@ -198,6 +206,8 @@ end
   end
 
   def test_cp
+    check_singleton :cp
+
     each_srcdest do |srcpath, destpath|
       cp srcpath, destpath
       assert_same_file srcpath, destpath
@@ -245,6 +255,8 @@ end
   end
 
   def test_cp_r
+    check_singleton :cp_r
+
     cp_r 'data', 'tmp'
     TARGETS.each do |fname|
       assert_same_file fname, "tmp/#{fname}"
@@ -299,6 +311,8 @@ end
   end
 
   def test_mv
+    check_singleton :mv
+
     mkdir 'tmp/dest'
     TARGETS.each do |fname|
       cp fname, 'tmp/mvsrc'
@@ -356,6 +370,8 @@ end
   end
 
   def test_rm
+    check_singleton :rm
+
     TARGETS.each do |fname|
       cp fname, 'tmp/rmsrc'
       rm 'tmp/rmsrc'
@@ -376,6 +392,8 @@ end
   end
 
   def test_rm_f
+    check_singleton :rm_f
+
     TARGETS.each do |fname|
       cp fname, 'tmp/rmsrc'
       rm_f 'tmp/rmsrc'
@@ -421,6 +439,8 @@ end
   end
 
   def test_rm_r
+    check_singleton :rm_r
+
     my_rm_rf 'tmpdatadir'
 
     Dir.mkdir 'tmpdatadir'
@@ -479,6 +499,64 @@ end
     assert_file_not_exist 'tmp/tmpdir3'
   end
 
+  def test_remove_entry_secure
+    check_singleton :remove_entry_secure
+
+    my_rm_rf 'tmpdatadir'
+
+    Dir.mkdir 'tmpdatadir'
+    remove_entry_secure 'tmpdatadir'
+    assert_file_not_exist 'tmpdatadir'
+
+    Dir.mkdir 'tmpdatadir'
+    remove_entry_secure 'tmpdatadir/'
+    assert_file_not_exist 'tmpdatadir'
+
+    Dir.mkdir 'tmp/tmpdir'
+    remove_entry_secure 'tmp/tmpdir/'
+    assert_file_not_exist 'tmp/tmpdir'
+    assert_file_exist     'tmp'
+
+    Dir.mkdir 'tmp/tmpdir'
+    remove_entry_secure 'tmp/tmpdir'
+    assert_file_not_exist 'tmp/tmpdir'
+    assert_file_exist     'tmp'
+
+    Dir.mkdir 'tmp/tmpdir'
+    File.open('tmp/tmpdir/a', 'w') {|f| f.puts 'dummy' }
+    File.open('tmp/tmpdir/b', 'w') {|f| f.puts 'dummy' }
+    File.open('tmp/tmpdir/c', 'w') {|f| f.puts 'dummy' }
+    remove_entry_secure 'tmp/tmpdir'
+    assert_file_not_exist 'tmp/tmpdir'
+    assert_file_exist     'tmp'
+
+    Dir.mkdir 'tmp/tmpdir'
+    File.open('tmp/tmpdir/a', 'w') {|f| f.puts 'dummy' }
+    File.open('tmp/tmpdir/c', 'w') {|f| f.puts 'dummy' }
+    remove_entry_secure 'tmp/tmpdir/a', true
+    remove_entry_secure 'tmp/tmpdir/b', true
+    remove_entry_secure 'tmp/tmpdir/c', true
+    assert_file_not_exist 'tmp/tmpdir/a'
+    assert_file_not_exist 'tmp/tmpdir/c'
+    Dir.rmdir 'tmp/tmpdir'
+
+if have_symlink?
+    # [ruby-talk:94635] a symlink to the directory
+    Dir.mkdir 'tmp/tmpdir'
+    File.symlink '..', 'tmp/tmpdir/symlink_to_dir'
+    remove_entry_secure 'tmp/tmpdir'
+    assert_file_not_exist 'tmp/tmpdir'
+    assert_file_exist     'tmp'
+end
+
+    # pathname
+    Dir.mkdir 'tmp/tmpdir1'; touch 'tmp/tmpdir1/tmp'
+    assert_nothing_raised {
+      remove_entry_secure Pathname.new('tmp/tmpdir1')
+    }
+    assert_file_not_exist 'tmp/tmpdir1'
+  end
+
   def test_with_big_file
     prepare_big_file
 
@@ -545,6 +623,8 @@ end
 
 if have_symlink?
   def test_ln_s
+    check_singleton :ln_s
+
     TARGETS.each do |fname|
       ln_s fname, 'tmp/lnsdest'
       assert FileTest.symlink?('tmp/lnsdest'), 'not symlink'
@@ -568,6 +648,8 @@ end
 
 if have_symlink?
   def test_ln_sf
+    check_singleton :ln_sf
+
     TARGETS.each do |fname|
       ln_sf fname, 'tmp/lnsdest'
       assert FileTest.symlink?('tmp/lnsdest'), 'not symlink'
@@ -590,6 +672,8 @@ if have_symlink?
 end
 
   def test_mkdir
+    check_singleton :mkdir
+
     my_rm_rf 'tmpdatadir'
     mkdir 'tmpdatadir'
     assert_directory 'tmpdatadir'
@@ -629,6 +713,8 @@ end
   end
 
   def test_mkdir_p
+    check_singleton :mkdir_p
+
     dirs = %w(
       tmpdir/dir/
       tmpdir/dir/./
@@ -692,6 +778,8 @@ end
   end
 
   def test_install
+    check_singleton :install
+
     File.open('tmp/aaa', 'w') {|f| f.puts 'aaa' }
     File.open('tmp/bbb', 'w') {|f| f.puts 'bbb' }
     install 'tmp/aaa', 'tmp/bbb', :mode => 0600
@@ -750,6 +838,8 @@ end
 
 if have_file_perm?
   def test_chmod
+    check_singleton :chmod
+
     touch 'tmp/a'
     chmod 0700, 'tmp/a'
     assert_equal 0700, File.stat('tmp/a').mode & 0777
@@ -758,6 +848,8 @@ if have_file_perm?
   end
 
   def test_chmod_R
+    check_singleton :chmod_R
+
     mkdir_p 'tmp/dir/dir'
     touch %w( tmp/dir/file tmp/dir/dir/file )
     chmod_R 0700, 'tmp/dir'
@@ -775,14 +867,18 @@ if have_file_perm?
 
   # FIXME: How can I test this method?
   def test_chown
+    check_singleton :chown
   end
 
   # FIXME: How can I test this method?
   def test_chown_R
+    check_singleton :chown_R
   end
 end
 
   def test_copy_entry
+    check_singleton :copy_entry
+
     each_srcdest do |srcpath, destpath|
       copy_entry srcpath, destpath
       assert_same_file srcpath, destpath
@@ -807,6 +903,8 @@ end
   end
 
   def test_copy_file
+    check_singleton :copy_file
+
     each_srcdest do |srcpath, destpath|
       copy_file srcpath, destpath
       assert_same_file srcpath, destpath
@@ -814,6 +912,7 @@ end
   end
 
   def test_copy_stream
+    check_singleton :copy_stream
     # IO
     each_srcdest do |srcpath, destpath|
       File.open(srcpath) {|src|
@@ -838,6 +937,7 @@ end
   end
 
   def test_remove_file
+    check_singleton :remove_file
     File.open('data/tmp', 'w') {|f| f.puts 'dummy' }
     remove_file 'data/tmp'
     assert_file_not_exist 'data/tmp'
@@ -850,6 +950,7 @@ end
   end
 
   def test_remove_dir
+    check_singleton :remove_dir
     Dir.mkdir 'data/tmpdir'
     File.open('data/tmpdir/a', 'w') {|f| f.puts 'dummy' }
     remove_dir 'data/tmpdir'
@@ -863,10 +964,12 @@ end
   end
 
   def test_compare_file
+    check_singleton :compare_file
     # FIXME
   end
 
   def test_compare_stream
+    check_singleton :compare_stream
     # FIXME
   end
 
@@ -885,6 +988,7 @@ end
   end
 
   def test_uptodate?
+    check_singleton :uptodate?
     prepare_time_data
     Dir.chdir('data') {
       assert(   uptodate?('newest', %w(old newer notexist)) )
@@ -904,4 +1008,75 @@ end
     }
   end
 
+  def test_cd
+    check_singleton :cd
+  end
+
+  def test_chdir
+    check_singleton :chdir
+  end
+
+  def test_getwd
+    check_singleton :getwd
+  end
+
+  def test_identical?
+    check_singleton :identical?
+  end
+
+  def test_link
+    check_singleton :link
+  end
+
+  def test_makedirs
+    check_singleton :makedirs
+  end
+
+  def test_mkpath
+    check_singleton :mkpath
+  end
+
+  def test_move
+    check_singleton :move
+  end
+
+  def test_rm_rf
+    check_singleton :rm_rf
+  end
+
+  def test_rmdir
+    check_singleton :rmdir
+  end
+
+  def test_rmtree
+    check_singleton :rmtree
+  end
+
+  def test_safe_unlink
+    check_singleton :safe_unlink
+  end
+
+  def test_symlink
+    check_singleton :symlink
+  end
+
+  def test_touch
+    check_singleton :touch
+  end
+
+  def test_collect_methods
+  end
+
+  def test_commands
+  end
+
+  def test_have_option?
+  end
+
+  def test_options
+  end
+
+  def test_options_of
+  end
+
 end