diff --git a/test/stdlib/CGI_test.rb b/test/stdlib/CGI_test.rb
index c88b05b2c..dfdff203b 100644
--- a/test/stdlib/CGI_test.rb
+++ b/test/stdlib/CGI_test.rb
@@ -7,37 +7,6 @@ class CGISingletonTest < Test::Unit::TestCase
   library "cgi"
   testing "singleton(::CGI)"
 
-  def test_new
-    ARGV.replace(%w(abc=001 def=002))
-    assert_send_type  "() -> void",
-                      CGI, :new
-    assert_send_type  "(?::String options) -> void",
-                      CGI, :new, 'html3'
-    assert_send_type  "(?::String options) ?{ (::String name, ::String value) -> void } -> void",
-                      CGI, :new, 'html3' do |name, value| name + value end
-    assert_send_type  "(::Hash[::Symbol, untyped] options_hash) -> void",
-                      CGI, :new, { tag_maker: 'html5', max_multipart_length: 2048 }
-    assert_send_type  "(::Hash[::Symbol, untyped] options_hash) ?{ (::String name, ::String value) -> void } -> void",
-                      CGI, :new, { tag_maker: 'html5', max_multipart_length: 2048 } do |name, value| name + value end
-  end
-
-  def test_accept_charset
-    assert_send_type  "() -> ::encoding",
-                      CGI, :accept_charset
-  end
-
-  def test_accept_charset=
-    assert_send_type  "(::String accept_charset) -> ::String",
-                      CGI, :accept_charset=, 'utf-8'
-    assert_send_type  "(::Encoding accept_charset) -> ::Encoding",
-                      CGI, :accept_charset=, Encoding::UTF_8
-  end
-
-  def test_parse
-    assert_send_type  "(::String query) -> ::Hash[::String, String | Array[String]]",
-                      CGI, :parse, 'a=hoge&b=1&c[]=test1&c[]=test2'
-  end
-
   def test_escapeURIComponent
     assert_send_type(
       "(String) -> String",
@@ -59,6 +28,41 @@ def test_unescapeURIComponent
       CGI, :unescapeURIComponent, ToStr.new("hogehoge")
     )
   end
+
+  # These methods are removed in Ruby 3.5.
+  unless RUBY_VERSION >= "3.5"
+    def test_new
+      ARGV.replace(%w(abc=001 def=002))
+      assert_send_type  "() -> void",
+                        CGI, :new
+
+      assert_send_type  "(?::String options) -> void",
+                        CGI, :new, 'html3'
+      assert_send_type  "(?::String options) ?{ (::String name, ::String value) -> void } -> void",
+                        CGI, :new, 'html3' do |name, value| name + value end
+      assert_send_type  "(::Hash[::Symbol, untyped] options_hash) -> void",
+                        CGI, :new, { tag_maker: 'html5', max_multipart_length: 2048 }
+      assert_send_type  "(::Hash[::Symbol, untyped] options_hash) ?{ (::String name, ::String value) -> void } -> void",
+                        CGI, :new, { tag_maker: 'html5', max_multipart_length: 2048 } do |name, value| name + value end
+    end
+
+    def test_accept_charset
+      assert_send_type  "() -> ::encoding",
+                        CGI, :accept_charset
+    end
+
+    def test_accept_charset=
+      assert_send_type  "(::String accept_charset) -> ::String",
+                        CGI, :accept_charset=, 'utf-8'
+      assert_send_type  "(::Encoding accept_charset) -> ::Encoding",
+                        CGI, :accept_charset=, Encoding::UTF_8
+    end
+
+    def test_parse
+      assert_send_type  "(::String query) -> ::Hash[::String, String | Array[String]]",
+                        CGI, :parse, 'a=hoge&b=1&c[]=test1&c[]=test2'
+    end
+  end
 end
 
 class CGITest < Test::Unit::TestCase
@@ -77,51 +81,54 @@ def test_print
                       CGI.new, :print, ''
   end
 
-  def test_http_header
-    assert_send_type  "() -> ::String",
-                      CGI.new, :http_header
-    assert_send_type  "(::String options) -> ::String",
-                      CGI.new, :http_header, 'text/csv'
-    assert_send_type  "(::Hash[::String, untyped] header_hash) -> ::String",
-                      CGI.new, :http_header, { 'type' => 'text/csv', 'nph' => false, 'length' => 1024 }
-    assert_send_type  "(::Hash[::Symbol, untyped] header_hash) -> ::String",
-                      CGI.new, :http_header, { type: 'text/csv', nph: false, length: 1024 }
-  end
-
-  def test_header
-    assert_send_type  "() -> ::String",
-                      CGI.new, :header
-    assert_send_type  "(::String options) -> ::String",
-                      CGI.new, :header, 'text/csv'
-    assert_send_type  "(::Hash[::String, untyped] header_hash) -> ::String",
-                      CGI.new, :header, { 'type' => 'text/csv', 'nph' => false, 'length' => 1024 }
-    assert_send_type  "(::Hash[::Symbol, untyped] header_hash) -> ::String",
-                      CGI.new, :header, { type: 'text/csv', nph: false, length: 1024 }
-  end
-
-  def test_nph?
-    assert_send_type  "() -> ::boolish",
-                      CGI.new, :nph?
-  end
-
-  def test_out
-    assert_send_type  "() { () -> void } -> void",
-                      CGI.new, :out do '' end
-    assert_send_type  "(::String content_type_string) { () -> String } -> void",
-                      CGI.new, :out, 'text/csv' do '' end
-    assert_send_type  "(::Hash[::String, untyped] header_hash) { () -> String } -> void",
-                      CGI.new, :out, { 'type' => 'text/csv', 'nph' => false, 'length' => 1024 } do '' end
-    assert_send_type  "(::Hash[::String | ::Symbol, untyped] header_hash) { () -> String } -> void",
-                      CGI.new, :out, { type: 'text/csv' } do '' end
-  end
-
-  def test_stdinput
-    assert_send_type  "() -> ::IO",
-                      CGI.new, :stdinput
-  end
-
-  def test_stdoutput
-    assert_send_type  "() -> ::IO",
-                      CGI.new, :stdoutput
+  # These methods are removed in Ruby 3.5.
+  unless RUBY_VERSION >= "3.5"
+    def test_http_header
+      assert_send_type  "() -> ::String",
+                        CGI.new, :http_header
+      assert_send_type  "(::String options) -> ::String",
+                        CGI.new, :http_header, 'text/csv'
+      assert_send_type  "(::Hash[::String, untyped] header_hash) -> ::String",
+                        CGI.new, :http_header, { 'type' => 'text/csv', 'nph' => false, 'length' => 1024 }
+      assert_send_type  "(::Hash[::Symbol, untyped] header_hash) -> ::String",
+                        CGI.new, :http_header, { type: 'text/csv', nph: false, length: 1024 }
+    end
+
+    def test_header
+      assert_send_type  "() -> ::String",
+                        CGI.new, :header
+      assert_send_type  "(::String options) -> ::String",
+                        CGI.new, :header, 'text/csv'
+      assert_send_type  "(::Hash[::String, untyped] header_hash) -> ::String",
+                        CGI.new, :header, { 'type' => 'text/csv', 'nph' => false, 'length' => 1024 }
+      assert_send_type  "(::Hash[::Symbol, untyped] header_hash) -> ::String",
+                        CGI.new, :header, { type: 'text/csv', nph: false, length: 1024 }
+    end
+
+    def test_nph?
+      assert_send_type  "() -> ::boolish",
+                        CGI.new, :nph?
+    end
+
+    def test_out
+      assert_send_type  "() { () -> void } -> void",
+                        CGI.new, :out do '' end
+      assert_send_type  "(::String content_type_string) { () -> String } -> void",
+                        CGI.new, :out, 'text/csv' do '' end
+      assert_send_type  "(::Hash[::String, untyped] header_hash) { () -> String } -> void",
+                        CGI.new, :out, { 'type' => 'text/csv', 'nph' => false, 'length' => 1024 } do '' end
+      assert_send_type  "(::Hash[::String | ::Symbol, untyped] header_hash) { () -> String } -> void",
+                        CGI.new, :out, { type: 'text/csv' } do '' end
+    end
+
+    def test_stdinput
+      assert_send_type  "() -> ::IO",
+                        CGI.new, :stdinput
+    end
+
+    def test_stdoutput
+      assert_send_type  "() -> ::IO",
+                        CGI.new, :stdoutput
+    end
   end
 end
diff --git a/test/stdlib/Pathname_test.rb b/test/stdlib/Pathname_test.rb
index 2e9fceec7..a70b86f00 100644
--- a/test/stdlib/Pathname_test.rb
+++ b/test/stdlib/Pathname_test.rb
@@ -28,6 +28,8 @@ def test_pwd
   end
 
   def test_initialize
+    omit "Pathname is developing in head" if RUBY_VERSION >= '3.5'
+
     assert_send_type '(String) -> Pathname',
                      Pathname, :new, 'foo'
     assert_send_type '(ToStr) -> Pathname',
@@ -43,6 +45,8 @@ class PathnameInstanceTest < Test::Unit::TestCase
   testing '::Pathname'
 
   def test_plus
+    omit "Pathname is developing in head" if RUBY_VERSION >= '3.5'
+
     assert_send_type '(Pathname) -> Pathname',
                      Pathname('foo'), :+, Pathname('bar')
     assert_send_type '(String) -> Pathname',
@@ -52,6 +56,8 @@ def test_plus
   end
 
   def test_slash
+    omit "Pathname is developing in head" if RUBY_VERSION >= '3.5'
+
     assert_send_type '(Pathname) -> Pathname',
                      Pathname('foo'), :/, Pathname('bar')
     assert_send_type '(String) -> Pathname',
@@ -380,6 +386,8 @@ def test_inspect
   end
 
   def test_join
+    omit "Pathname is developing in head" if RUBY_VERSION >= '3.5'
+
     assert_send_type '() -> Pathname',
                      Pathname('.'), :join
     assert_send_type '(String) -> Pathname',
@@ -602,6 +610,8 @@ def test_relative?
   end
 
   def test_relative_path_from
+    omit "Pathname is developing in head" if RUBY_VERSION >= '3.5'
+
     assert_send_type '(Pathname) -> Pathname',
                      Pathname('.'), :relative_path_from, Pathname('.')
     assert_send_type '(String) -> Pathname',
@@ -824,6 +834,8 @@ class PathnameKernelTest < Test::Unit::TestCase
   testing '::Kernel'
 
   def test_Pathname
+    omit "Pathname is developing in head" if RUBY_VERSION >= '3.5'
+
     with_string("Gemfile") do
       assert_send_type(
         "(::string) -> ::Pathname",
diff --git a/test/stdlib/Ractor_test.rb b/test/stdlib/Ractor_test.rb
index f2d0897db..d25dfc965 100644
--- a/test/stdlib/Ractor_test.rb
+++ b/test/stdlib/Ractor_test.rb
@@ -74,14 +74,18 @@ def test_recv
   end
 
   def test_receive_if
+    omit "Ractor.receive_if is not implemented" if RUBY_VERSION >= "3.5"
+
     Ractor.current.send 42
     assert_send_type "() { (Integer) -> bool } -> Integer",
                      Ractor, :receive_if do |n| n == 42 end
   end
 
   def test_select
-    r1 = Ractor.new { loop { Ractor.yield 42 } }
-    r2 = Ractor.new { loop { Ractor.yield 43 } }
+    omit "Ractor#yield is not implemented" if RUBY_VERSION >= "3.5"
+
+    r1 = Ractor.new {|r| loop { Ractor.yield 42 } }
+    r2 = Ractor.new {|r| loop { Ractor.yield 43 } }
 
     assert_send_type "(Ractor) -> [Ractor, Integer]",
                      Ractor, :select, r1
@@ -115,6 +119,8 @@ def test_store_if_absent
   end
 
   def test_yield
+    omit "Ractor#yield is not implemented" if RUBY_VERSION >= "3.5"
+
     Ractor.new(Ractor.current) { |r| loop { r.take } }
 
     assert_send_type "(Integer) -> untyped",
@@ -153,12 +159,16 @@ def test_aset
   end
 
   def test_close_incoming
+    omit "Ractor#close_incoming is not implemented" if RUBY_VERSION >= "3.5"
+    
     r = Ractor.new {}
     assert_send_type "() -> bool",
                      r, :close_incoming
   end
 
   def test_close_outgoing
+    omit "Ractor#close_outgoing is not implemented" if RUBY_VERSION >= "3.5"
+
     r = Ractor.new {}
     assert_send_type "() -> bool",
                      r, :close_outgoing
@@ -190,6 +200,8 @@ def test_send
   end
 
   def test_take
+    omit "Ractor#take is not implemented" if RUBY_VERSION >= "3.5"
+
     r = Ractor.new { 42 }
 
     assert_send_type "() -> Integer",