diff --git a/.github/workflows/ruby.yml b/.github/workflows/ruby.yml
index acd9bf63a..ede0364e1 100644
--- a/.github/workflows/ruby.yml
+++ b/.github/workflows/ruby.yml
@@ -44,8 +44,6 @@ jobs:
           bundler: none
       - name: Set working directory as safe
         run: git config --global --add safe.directory $(pwd)
-      - name: Set up permission
-        run: chmod -R o-w /opt/hostedtoolcache/Ruby
       - name: Install dependencies
         run: |
           sudo apt-get update
@@ -90,8 +88,6 @@ jobs:
           bundler-cache: none
       - name: Set working directory as safe
         run: git config --global --add safe.directory $(pwd)
-      - name: Set up permission
-        run: chmod -R o-w /opt/hostedtoolcache/Ruby
       - name: Install dependencies
         run: |
           sudo apt-get update
diff --git a/.github/workflows/typecheck.yml b/.github/workflows/typecheck.yml
index 0afc49b99..5f737028a 100644
--- a/.github/workflows/typecheck.yml
+++ b/.github/workflows/typecheck.yml
@@ -20,8 +20,6 @@ jobs:
           bundler: none
       - name: Set working directory as safe
         run: git config --global --add safe.directory $(pwd)
-      - name: Set up permission
-        run: chmod -R o-w /opt/hostedtoolcache/Ruby
       - name: Install dependencies
         run: |
           sudo apt-get update
diff --git a/test/stdlib/CGI_test.rb b/test/stdlib/CGI_test.rb
index ddcfefc7b..c88b05b2c 100644
--- a/test/stdlib/CGI_test.rb
+++ b/test/stdlib/CGI_test.rb
@@ -68,6 +68,7 @@ class CGITest < Test::Unit::TestCase
   testing "::CGI"
 
   def setup
+    super
     ARGV.replace(%w(abc=001 def=002))
   end
 
diff --git a/test/stdlib/Forwardable_test.rb b/test/stdlib/Forwardable_test.rb
index 755e8c843..e92e1f1e6 100644
--- a/test/stdlib/Forwardable_test.rb
+++ b/test/stdlib/Forwardable_test.rb
@@ -71,6 +71,7 @@ class SingleForwardableTest < Test::Unit::TestCase
   testing "::SingleForwardable"
 
   def setup
+    super
     @tested = Object.new
     @tested.extend SingleForwardable
   end
diff --git a/test/stdlib/Minitest_test.rb b/test/stdlib/Minitest_test.rb
index 34c2fc6c4..f8c1cb511 100644
--- a/test/stdlib/Minitest_test.rb
+++ b/test/stdlib/Minitest_test.rb
@@ -51,9 +51,10 @@ class MinitestTestLifecycleHooksTest < Test::Unit::TestCase
 
   class LifecycleSetup < Minitest::Test
     def setup
+      super
       @foo = 123
     end
-  end  
+  end
 
   def test_setup_return_type_void
     test = LifecycleSetup.new("setup")
diff --git a/test/stdlib/Ractor_test.rb b/test/stdlib/Ractor_test.rb
index 9ed177c17..f2d0897db 100644
--- a/test/stdlib/Ractor_test.rb
+++ b/test/stdlib/Ractor_test.rb
@@ -132,6 +132,8 @@ class RactorInstanceTest < Test::Unit::TestCase
   testing "::Ractor"
 
   def test_aref
+    omit "Accessing ractor local storage" if RUBY_VERSION >= "3.5"
+
     r = Ractor.new {}
     r['foo'] = 'bar'
     assert_send_type "(String) -> untyped",
@@ -141,6 +143,8 @@ def test_aref
   end
 
   def test_aset
+    omit "Accessing ractor local storage" if RUBY_VERSION >= "3.5"
+
     r = Ractor.new {}
     assert_send_type "(String, String) -> String",
                      r, :[]=, 'foo', 'bar'
diff --git a/test/stdlib/uri/rfc2396_parser_test.rb b/test/stdlib/uri/rfc2396_parser_test.rb
index 3e6f35a05..215eecd34 100644
--- a/test/stdlib/uri/rfc2396_parser_test.rb
+++ b/test/stdlib/uri/rfc2396_parser_test.rb
@@ -20,6 +20,7 @@ class URIRFC2396_ParserInstanceTest < Test::Unit::TestCase
   testing "::URI::RFC2396_Parser"
 
   def setup
+    super
     @instance = URI::RFC2396_Parser.new
   end