diff --git a/test/test_rdoc_options.rb b/test/test_rdoc_options.rb
index 394d155241..baef2d860e 100644
--- a/test/test_rdoc_options.rb
+++ b/test/test_rdoc_options.rb
@@ -18,6 +18,7 @@ def teardown
 
   def test_check_files
     skip "assumes UNIX permission model" if /mswin|mingw/ =~ RUBY_PLATFORM
+    skip "assumes that euid is not root" if Process.euid == 0
 
     out, err = capture_io do
       temp_dir do
diff --git a/test/test_rdoc_rdoc.rb b/test/test_rdoc_rdoc.rb
index 4014ecfa54..3bce54b243 100644
--- a/test/test_rdoc_rdoc.rb
+++ b/test/test_rdoc_rdoc.rb
@@ -350,6 +350,7 @@ def test_parse_file_encoding
 
   def test_parse_file_forbidden
     skip 'chmod not supported' if Gem.win_platform?
+    skip "assumes that euid is not root" if Process.euid == 0
 
     @rdoc.store = RDoc::Store.new
 
diff --git a/test/test_rdoc_rubygems_hook.rb b/test/test_rdoc_rubygems_hook.rb
index 2fb79ff577..ff0c29ae1b 100644
--- a/test/test_rdoc_rubygems_hook.rb
+++ b/test/test_rdoc_rubygems_hook.rb
@@ -200,6 +200,8 @@ def test_remove
 
   def test_remove_unwritable
     skip 'chmod not supported' if Gem.win_platform?
+    skip "assumes that euid is not root" if Process.euid == 0
+
     FileUtils.mkdir_p @a.base_dir
     FileUtils.chmod 0, @a.base_dir
 
@@ -228,6 +230,8 @@ def test_setup
 
   def test_setup_unwritable
     skip 'chmod not supported' if Gem.win_platform?
+    skip "assumes that euid is not root" if Process.euid == 0
+
     FileUtils.mkdir_p @a.doc_dir
     FileUtils.chmod 0, @a.doc_dir