diff --git a/core/io/binread_spec.rb b/core/io/binread_spec.rb
index 418e89213b..9e36b84da9 100644
--- a/core/io/binread_spec.rb
+++ b/core/io/binread_spec.rb
@@ -45,7 +45,7 @@
     -> { IO.binread @fname, 0, -1  }.should raise_error(Errno::EINVAL)
   end
 
-  ruby_version_is "3.3" do
+  ruby_version_is "3.3"..."4.0" do
     # https://bugs.ruby-lang.org/issues/19630
     it "warns about deprecation given a path with a pipe" do
       cmd = "|echo ok"
diff --git a/core/io/foreach_spec.rb b/core/io/foreach_spec.rb
index c361d27879..6abe8901ba 100644
--- a/core/io/foreach_spec.rb
+++ b/core/io/foreach_spec.rb
@@ -14,33 +14,35 @@
     IO.foreach(@name) { $..should == @count += 1 }
   end
 
-  describe "when the filename starts with |" do
-    it "gets data from the standard out of the subprocess" do
-      cmd = "|sh -c 'echo hello;echo line2'"
-      platform_is :windows do
-        cmd = "|cmd.exe /C echo hello&echo line2"
-      end
+  ruby_version_is ""..."4.0" do
+    describe "when the filename starts with |" do
+      it "gets data from the standard out of the subprocess" do
+        cmd = "|sh -c 'echo hello;echo line2'"
+        platform_is :windows do
+          cmd = "|cmd.exe /C echo hello&echo line2"
+        end
 
-      suppress_warning do # https://bugs.ruby-lang.org/issues/19630
-        IO.foreach(cmd) { |l| ScratchPad << l }
+        suppress_warning do # https://bugs.ruby-lang.org/issues/19630
+          IO.foreach(cmd) { |l| ScratchPad << l }
+        end
+        ScratchPad.recorded.should == ["hello\n", "line2\n"]
       end
-      ScratchPad.recorded.should == ["hello\n", "line2\n"]
-    end
 
-    platform_is_not :windows do
-      it "gets data from a fork when passed -" do
-        parent_pid = $$
+      platform_is_not :windows do
+        it "gets data from a fork when passed -" do
+          parent_pid = $$
 
-        suppress_warning do # https://bugs.ruby-lang.org/issues/19630
-          IO.foreach("|-") { |l| ScratchPad << l }
-        end
+          suppress_warning do # https://bugs.ruby-lang.org/issues/19630
+            IO.foreach("|-") { |l| ScratchPad << l }
+          end
 
-        if $$ == parent_pid
-          ScratchPad.recorded.should == ["hello\n", "from a fork\n"]
-        else # child
-          puts "hello"
-          puts "from a fork"
-          exit!
+          if $$ == parent_pid
+            ScratchPad.recorded.should == ["hello\n", "from a fork\n"]
+          else # child
+            puts "hello"
+            puts "from a fork"
+            exit!
+          end
         end
       end
     end
diff --git a/core/io/read_spec.rb b/core/io/read_spec.rb
index 567daa55df..988ec2ce30 100644
--- a/core/io/read_spec.rb
+++ b/core/io/read_spec.rb
@@ -168,76 +168,78 @@
   end
 end
 
-describe "IO.read from a pipe" do
-  it "runs the rest as a subprocess and returns the standard output" do
-    cmd = "|sh -c 'echo hello'"
-    platform_is :windows do
-      cmd = "|cmd.exe /C echo hello"
-    end
-
-    suppress_warning do # https://bugs.ruby-lang.org/issues/19630
-      IO.read(cmd).should == "hello\n"
-    end
-  end
-
-  platform_is_not :windows do
-    it "opens a pipe to a fork if the rest is -" do
-      str = nil
-      suppress_warning do # https://bugs.ruby-lang.org/issues/19630
-        str = IO.read("|-")
+ruby_version_is ""..."4.0" do
+  describe "IO.read from a pipe" do
+    it "runs the rest as a subprocess and returns the standard output" do
+      cmd = "|sh -c 'echo hello'"
+      platform_is :windows do
+        cmd = "|cmd.exe /C echo hello"
       end
 
-      if str # parent
-        str.should == "hello from child\n"
-      else #child
-        puts "hello from child"
-        exit!
+      suppress_warning do # https://bugs.ruby-lang.org/issues/19630
+        IO.read(cmd).should == "hello\n"
       end
     end
-  end
 
-  it "reads only the specified number of bytes requested" do
-    cmd = "|sh -c 'echo hello'"
-    platform_is :windows do
-      cmd = "|cmd.exe /C echo hello"
-    end
+    platform_is_not :windows do
+      it "opens a pipe to a fork if the rest is -" do
+        str = nil
+        suppress_warning do # https://bugs.ruby-lang.org/issues/19630
+          str = IO.read("|-")
+        end
 
-    suppress_warning do # https://bugs.ruby-lang.org/issues/19630
-      IO.read(cmd, 1).should == "h"
+        if str # parent
+          str.should == "hello from child\n"
+        else #child
+          puts "hello from child"
+          exit!
+        end
+      end
     end
-  end
 
-  platform_is_not :windows do
-    it "raises Errno::ESPIPE if passed an offset" do
-      -> {
-        suppress_warning do # https://bugs.ruby-lang.org/issues/19630
-          IO.read("|sh -c 'echo hello'", 1, 1)
-        end
-      }.should raise_error(Errno::ESPIPE)
+    it "reads only the specified number of bytes requested" do
+      cmd = "|sh -c 'echo hello'"
+      platform_is :windows do
+        cmd = "|cmd.exe /C echo hello"
+      end
+
+      suppress_warning do # https://bugs.ruby-lang.org/issues/19630
+        IO.read(cmd, 1).should == "h"
+      end
     end
-  end
 
-  quarantine! do # The process tried to write to a nonexistent pipe.
-    platform_is :windows do
-      # TODO: It should raise Errno::ESPIPE on Windows as well
-      # once https://bugs.ruby-lang.org/issues/12230 is fixed.
-      it "raises Errno::EINVAL if passed an offset" do
+    platform_is_not :windows do
+      it "raises Errno::ESPIPE if passed an offset" do
         -> {
           suppress_warning do # https://bugs.ruby-lang.org/issues/19630
-            IO.read("|cmd.exe /C echo hello", 1, 1)
+            IO.read("|sh -c 'echo hello'", 1, 1)
           end
-        }.should raise_error(Errno::EINVAL)
+        }.should raise_error(Errno::ESPIPE)
       end
     end
-  end
 
-  ruby_version_is "3.3" do
-    # https://bugs.ruby-lang.org/issues/19630
-    it "warns about deprecation given a path with a pipe" do
-      cmd = "|echo ok"
-      -> {
-        IO.read(cmd)
-      }.should complain(/IO process creation with a leading '\|'/)
+    quarantine! do # The process tried to write to a nonexistent pipe.
+      platform_is :windows do
+        # TODO: It should raise Errno::ESPIPE on Windows as well
+        # once https://bugs.ruby-lang.org/issues/12230 is fixed.
+        it "raises Errno::EINVAL if passed an offset" do
+          -> {
+            suppress_warning do # https://bugs.ruby-lang.org/issues/19630
+              IO.read("|cmd.exe /C echo hello", 1, 1)
+            end
+          }.should raise_error(Errno::EINVAL)
+        end
+      end
+    end
+
+    ruby_version_is "3.3" do
+      # https://bugs.ruby-lang.org/issues/19630
+      it "warns about deprecation" do
+        cmd = "|echo ok"
+        -> {
+          IO.read(cmd)
+        }.should complain(/IO process creation with a leading '\|'/)
+      end
     end
   end
 end
diff --git a/core/io/readlines_spec.rb b/core/io/readlines_spec.rb
index 3a6ff3d0f3..b4770775d1 100644
--- a/core/io/readlines_spec.rb
+++ b/core/io/readlines_spec.rb
@@ -174,45 +174,47 @@
     $_.should == "test"
   end
 
-  describe "when passed a string that starts with a |" do
-    it "gets data from the standard out of the subprocess" do
-      cmd = "|sh -c 'echo hello;echo line2'"
-      platform_is :windows do
-        cmd = "|cmd.exe /C echo hello&echo line2"
-      end
-
-      lines = nil
-      suppress_warning do # https://bugs.ruby-lang.org/issues/19630
-        lines = IO.readlines(cmd)
-      end
-      lines.should == ["hello\n", "line2\n"]
-    end
+  ruby_version_is ""..."4.0" do
+    describe "when passed a string that starts with a |" do
+      it "gets data from the standard out of the subprocess" do
+        cmd = "|sh -c 'echo hello;echo line2'"
+        platform_is :windows do
+          cmd = "|cmd.exe /C echo hello&echo line2"
+        end
 
-    platform_is_not :windows do
-      it "gets data from a fork when passed -" do
         lines = nil
         suppress_warning do # https://bugs.ruby-lang.org/issues/19630
-          lines = IO.readlines("|-")
+          lines = IO.readlines(cmd)
         end
+        lines.should == ["hello\n", "line2\n"]
+      end
 
-        if lines # parent
-          lines.should == ["hello\n", "from a fork\n"]
-        else
-          puts "hello"
-          puts "from a fork"
-          exit!
+      platform_is_not :windows do
+        it "gets data from a fork when passed -" do
+          lines = nil
+          suppress_warning do # https://bugs.ruby-lang.org/issues/19630
+            lines = IO.readlines("|-")
+          end
+
+          if lines # parent
+            lines.should == ["hello\n", "from a fork\n"]
+          else
+            puts "hello"
+            puts "from a fork"
+            exit!
+          end
         end
       end
     end
-  end
 
-  ruby_version_is "3.3" do
-    # https://bugs.ruby-lang.org/issues/19630
-    it "warns about deprecation given a path with a pipe" do
-      cmd = "|echo ok"
-      -> {
-        IO.readlines(cmd)
-      }.should complain(/IO process creation with a leading '\|'/)
+    ruby_version_is "3.3" do
+      # https://bugs.ruby-lang.org/issues/19630
+      it "warns about deprecation given a path with a pipe" do
+        cmd = "|echo ok"
+        -> {
+          IO.readlines(cmd)
+        }.should complain(/IO process creation with a leading '\|'/)
+      end
     end
   end
 
diff --git a/core/io/write_spec.rb b/core/io/write_spec.rb
index 4a26f8dbaf..e58100f846 100644
--- a/core/io/write_spec.rb
+++ b/core/io/write_spec.rb
@@ -220,7 +220,7 @@
       end
     end
 
-    ruby_version_is "3.3" do
+    ruby_version_is "3.3"..."4.0" do
       # https://bugs.ruby-lang.org/issues/19630
       it "warns about deprecation given a path with a pipe" do
         -> {
diff --git a/core/kernel/open_spec.rb b/core/kernel/open_spec.rb
index 6d00af395d..b967d5044b 100644
--- a/core/kernel/open_spec.rb
+++ b/core/kernel/open_spec.rb
@@ -27,64 +27,66 @@
     open(@name, "r") { |f| f.gets }.should == @content
   end
 
-  platform_is_not :windows, :wasi do
-    it "opens an io when path starts with a pipe" do
-      suppress_warning do # https://bugs.ruby-lang.org/issues/19630
-        @io = open("|date")
+  ruby_version_is ""..."4.0" do
+    platform_is_not :windows, :wasi do
+      it "opens an io when path starts with a pipe" do
+        suppress_warning do # https://bugs.ruby-lang.org/issues/19630
+          @io = open("|date")
+        end
+        begin
+          @io.should be_kind_of(IO)
+          @io.read
+        ensure
+          @io.close
+        end
       end
-      begin
-        @io.should be_kind_of(IO)
-        @io.read
-      ensure
-        @io.close
-      end
-    end
 
-    it "opens an io when called with a block" do
-      suppress_warning do # https://bugs.ruby-lang.org/issues/19630
-        @output = open("|date") { |f| f.read }
+      it "opens an io when called with a block" do
+        suppress_warning do # https://bugs.ruby-lang.org/issues/19630
+          @output = open("|date") { |f| f.read }
+        end
+        @output.should_not == ''
       end
-      @output.should_not == ''
-    end
 
-    it "opens an io for writing" do
-      suppress_warning do # https://bugs.ruby-lang.org/issues/19630
-        -> {
-          bytes = open("|cat", "w") { |io| io.write(".") }
-          bytes.should == 1
-        }.should output_to_fd(".")
+      it "opens an io for writing" do
+        suppress_warning do # https://bugs.ruby-lang.org/issues/19630
+          -> {
+            bytes = open("|cat", "w") { |io| io.write(".") }
+            bytes.should == 1
+          }.should output_to_fd(".")
+        end
       end
     end
-  end
 
-  platform_is :windows do
-    it "opens an io when path starts with a pipe" do
-      suppress_warning do # https://bugs.ruby-lang.org/issues/19630
-        @io = open("|date /t")
+    platform_is :windows do
+      it "opens an io when path starts with a pipe" do
+        suppress_warning do # https://bugs.ruby-lang.org/issues/19630
+          @io = open("|date /t")
+        end
+        begin
+          @io.should be_kind_of(IO)
+          @io.read
+        ensure
+          @io.close
+        end
       end
-      begin
-        @io.should be_kind_of(IO)
-        @io.read
-      ensure
-        @io.close
-      end
-    end
 
-    it "opens an io when called with a block" do
-      suppress_warning do # https://bugs.ruby-lang.org/issues/19630
-        @output = open("|date /t") { |f| f.read }
+      it "opens an io when called with a block" do
+        suppress_warning do # https://bugs.ruby-lang.org/issues/19630
+          @output = open("|date /t") { |f| f.read }
+        end
+        @output.should_not == ''
       end
-      @output.should_not == ''
     end
-  end
 
-  ruby_version_is "3.3" do
-    # https://bugs.ruby-lang.org/issues/19630
-    it "warns about deprecation given a path with a pipe" do
-      cmd = "|echo ok"
-      -> {
-        open(cmd) { |f| f.read }
-      }.should complain(/Kernel#open with a leading '\|'/)
+    ruby_version_is "3.3" do
+      # https://bugs.ruby-lang.org/issues/19630
+      it "warns about deprecation given a path with a pipe" do
+        cmd = "|echo ok"
+        -> {
+          open(cmd) { |f| f.read }
+        }.should complain(/Kernel#open with a leading '\|'/)
+      end
     end
   end
 
diff --git a/core/math/lgamma_spec.rb b/core/math/lgamma_spec.rb
index 33e7836448..2bf350993e 100644
--- a/core/math/lgamma_spec.rb
+++ b/core/math/lgamma_spec.rb
@@ -5,10 +5,8 @@
     Math.lgamma(0).should == [infinity_value, 1]
   end
 
-  platform_is_not :windows do
-    it "returns [Infinity, 1] when passed -1" do
-      Math.lgamma(-1).should == [infinity_value, 1]
-    end
+  it "returns [Infinity, ...] when passed -1" do
+    Math.lgamma(-1)[0].should == infinity_value
   end
 
   it "returns [Infinity, -1] when passed -0.0" do
@@ -47,8 +45,7 @@
     Math.lgamma(infinity_value).should == [infinity_value, 1]
   end
 
-  it "returns [NaN, 1] when passed NaN" do
-    Math.lgamma(nan_value)[0].nan?.should be_true
-    Math.lgamma(nan_value)[1].should == 1
+  it "returns [NaN, ...] when passed NaN" do
+    Math.lgamma(nan_value)[0].should.nan?
   end
 end
diff --git a/core/symbol/inspect_spec.rb b/core/symbol/inspect_spec.rb
index 26229da944..df4566c48e 100644
--- a/core/symbol/inspect_spec.rb
+++ b/core/symbol/inspect_spec.rb
@@ -6,7 +6,7 @@
     :fred?     => ":fred?",
     :fred!     => ":fred!",
     :BAD!      => ":BAD!",
-    :_BAD!      => ":_BAD!",
+    :_BAD!     => ":_BAD!",
     :$ruby     => ":$ruby",
     :@ruby     => ":@ruby",
     :@@ruby    => ":@@ruby",
@@ -66,9 +66,9 @@
     :~         => ":~",
     :|         => ":|",
 
-    :"!"       => [":\"!\"",  ":!" ],
-    :"!="      => [":\"!=\"", ":!="],
-    :"!~"      => [":\"!~\"", ":!~"],
+    :"!"       => ":!",
+    :"!="      => ":!=",
+    :"!~"      => ":!~",
     :"\$"      => ":\"$\"", # for justice!
     :"&&"      => ":\"&&\"",
     :"'"       => ":\"\'\"",
@@ -97,13 +97,14 @@
     :" foo"    => ":\" foo\"",
     :" "       => ":\" \"",
 
-    :"ê"       => ":ê",
-    :"测"      => ":测",
-    :"🦊"      => ":🦊",
+    :"ê"       => [":ê", ":\"\\u00EA\""],
+    :"测"      => [":测", ":\"\\u6D4B\""],
+    :"🦊"      => [":🦊", ":\"\\u{1F98A}\""],
   }
 
+  expected_by_encoding = Encoding::default_external == Encoding::UTF_8 ? 0 : 1
   symbols.each do |input, expected|
-    expected = expected[1] if expected.is_a?(Array)
+    expected = expected[expected_by_encoding] if expected.is_a?(Array)
     it "returns self as a symbol literal for #{expected}" do
       input.inspect.should == expected
     end
diff --git a/language/pattern_matching_spec.rb b/language/pattern_matching_spec.rb
index cb4f5864d7..c1a6f0e4d6 100644
--- a/language/pattern_matching_spec.rb
+++ b/language/pattern_matching_spec.rb
@@ -493,7 +493,7 @@
           in [0, 0] | [0, a]
           end
         RUBY
-      }.should raise_error(SyntaxError, /illegal variable in alternative pattern/)
+      }.should raise_error(SyntaxError)
     end
 
     it "support underscore prefixed variables in alternation" do
diff --git a/language/regexp_spec.rb b/language/regexp_spec.rb
index 0cd9584549..dbf341b19e 100644
--- a/language/regexp_spec.rb
+++ b/language/regexp_spec.rb
@@ -112,7 +112,7 @@
     /foo.(?<=\d)/.match("fooA foo1").to_a.should == ["foo1"]
   end
 
-  ruby_bug "#13671", ""..."3.6" do # https://bugs.ruby-lang.org/issues/13671
+  ruby_bug "#13671", ""..."3.5" do # https://bugs.ruby-lang.org/issues/13671
     it "handles a lookbehind with ss characters" do
       r =  Regexp.new("(?<!dss)", Regexp::IGNORECASE)
       r.should =~ "✨"
diff --git a/library/erb/new_spec.rb b/library/erb/new_spec.rb
index ec1be5c234..f8192bff99 100644
--- a/library/erb/new_spec.rb
+++ b/library/erb/new_spec.rb
@@ -139,17 +139,19 @@
     ->{ ERB.new("<%= list %>").result }.should raise_error(NameError)
   end
 
-  describe "warning about arguments" do
-    it "warns when passed safe_level and later arguments" do
-      -> {
-        ERB.new(@eruby_str, nil, '%')
-      }.should complain(/warning: Passing safe_level with the 2nd argument of ERB.new is deprecated. Do not use it, and specify other arguments as keyword arguments./)
-    end
-
-    it "does not warn when passed arguments as keyword argument" do
-      -> {
-        ERB.new(@eruby_str, trim_mode: '%')
-      }.should_not complain(/warning: Passing safe_level with the 2nd argument of ERB.new is deprecated. Do not use it, and specify other arguments as keyword arguments./)
+  version_is ERB.const_get(:VERSION, false), ""..."6.0.0" do
+    describe "warning about arguments" do
+      it "warns when passed safe_level and later arguments" do
+        -> {
+          ERB.new(@eruby_str, nil, '%')
+        }.should complain(/warning: Passing safe_level with the 2nd argument of ERB.new is deprecated. Do not use it, and specify other arguments as keyword arguments./)
+      end
+
+      it "does not warn when passed arguments as keyword argument" do
+        -> {
+          ERB.new(@eruby_str, trim_mode: '%')
+        }.should_not complain(/warning: Passing safe_level with the 2nd argument of ERB.new is deprecated. Do not use it, and specify other arguments as keyword arguments./)
+      end
     end
   end
 end
diff --git a/library/openssl/digest/initialize_spec.rb b/library/openssl/digest/initialize_spec.rb
index 1cd0409c4d..b5911716ca 100644
--- a/library/openssl/digest/initialize_spec.rb
+++ b/library/openssl/digest/initialize_spec.rb
@@ -23,18 +23,14 @@
       OpenSSL::Digest.new("sha512").name.should ==  "SHA512"
     end
 
-    it "throws an error when called with an unknown digest" do
-      -> { OpenSSL::Digest.new("wd40") }.should raise_error(RuntimeError, /Unsupported digest algorithm \(wd40\)/)
+    version_is OpenSSL::VERSION, "4.0.0" do
+      it "throws an error when called with an unknown digest" do
+        -> { OpenSSL::Digest.new("wd40") }.should raise_error(OpenSSL::Digest::DigestError, /wd40/)
+      end
     end
 
     it "cannot be called with a symbol" do
-      -> { OpenSSL::Digest.new(:SHA1) }.should raise_error(TypeError, /wrong argument type Symbol/)
-    end
-
-    it "does not call #to_str on the argument" do
-      name = mock("digest name")
-      name.should_not_receive(:to_str)
-      -> { OpenSSL::Digest.new(name) }.should raise_error(TypeError, /wrong argument type/)
+      -> { OpenSSL::Digest.new(:SHA1) }.should raise_error(TypeError)
     end
   end
 
@@ -62,7 +58,7 @@
   end
 
   it "cannot be called with a digest class" do
-    -> { OpenSSL::Digest.new(OpenSSL::Digest::SHA1) }.should raise_error(TypeError, /wrong argument type Class/)
+    -> { OpenSSL::Digest.new(OpenSSL::Digest::SHA1) }.should raise_error(TypeError)
   end
 
   context "when called without an initial String argument" do
diff --git a/library/openssl/kdf/pbkdf2_hmac_spec.rb b/library/openssl/kdf/pbkdf2_hmac_spec.rb
index 40f8597275..1112972060 100644
--- a/library/openssl/kdf/pbkdf2_hmac_spec.rb
+++ b/library/openssl/kdf/pbkdf2_hmac_spec.rb
@@ -107,21 +107,15 @@
   it "raises a TypeError when hash is neither a String nor an OpenSSL::Digest" do
     -> {
       OpenSSL::KDF.pbkdf2_hmac("secret", **@defaults, hash: Object.new)
-    }.should raise_error(TypeError, "wrong argument type Object (expected OpenSSL/Digest)")
+    }.should raise_error(TypeError)
   end
 
-  it "raises a TypeError when hash is neither a String nor an OpenSSL::Digest, it does not try to call #to_str" do
-    hash = mock("hash")
-    hash.should_not_receive(:to_str)
-    -> {
-      OpenSSL::KDF.pbkdf2_hmac("secret", **@defaults, hash: hash)
-    }.should raise_error(TypeError, "wrong argument type MockObject (expected OpenSSL/Digest)")
-  end
-
-  it "raises a RuntimeError for unknown digest algorithms" do
-    -> {
-      OpenSSL::KDF.pbkdf2_hmac("secret", **@defaults, hash: "wd40")
-    }.should raise_error(RuntimeError, /Unsupported digest algorithm \(wd40\)/)
+  version_is OpenSSL::VERSION, "4.0.0" do
+    it "raises a OpenSSL::Digest::DigestError for unknown digest algorithms" do
+      -> {
+        OpenSSL::KDF.pbkdf2_hmac("secret", **@defaults, hash: "wd40")
+      }.should raise_error(OpenSSL::Digest::DigestError, /wd40/)
+    end
   end
 
   it "treats salt as a required keyword" do
diff --git a/library/rbconfig/unicode_emoji_version_spec.rb b/library/rbconfig/unicode_emoji_version_spec.rb
index 2c6d1f4e93..521a750bf7 100644
--- a/library/rbconfig/unicode_emoji_version_spec.rb
+++ b/library/rbconfig/unicode_emoji_version_spec.rb
@@ -9,9 +9,9 @@
   end
 
   # Caution: ruby_version_is means is_or_later
-  ruby_version_is "3.5" do
-    it "is 16.0" do
-      RbConfig::CONFIG['UNICODE_EMOJI_VERSION'].should == "16.0"
+  ruby_version_is "4.0" do
+    it "is 17.0" do
+      RbConfig::CONFIG['UNICODE_EMOJI_VERSION'].should == "17.0"
     end
   end
 end
diff --git a/library/rbconfig/unicode_version_spec.rb b/library/rbconfig/unicode_version_spec.rb
index 961bb989a5..5cdde74f79 100644
--- a/library/rbconfig/unicode_version_spec.rb
+++ b/library/rbconfig/unicode_version_spec.rb
@@ -9,9 +9,9 @@
   end
 
   # Caution: ruby_version_is means is_or_later
-  ruby_version_is "3.5" do
-    it "is 16.0.0" do
-      RbConfig::CONFIG['UNICODE_VERSION'].should == "16.0.0"
+  ruby_version_is "4.0" do
+    it "is 17.0.0" do
+      RbConfig::CONFIG['UNICODE_VERSION'].should == "17.0.0"
     end
   end
 end
diff --git a/library/stringscanner/clear_spec.rb b/library/stringscanner/clear_spec.rb
deleted file mode 100644
index 7ae089704a..0000000000
--- a/library/stringscanner/clear_spec.rb
+++ /dev/null
@@ -1,18 +0,0 @@
-require_relative '../../spec_helper'
-require_relative 'shared/terminate'
-require 'strscan'
-
-describe "StringScanner#clear" do
-  it_behaves_like :strscan_terminate, :clear
-
-  it "warns in verbose mode that the method is obsolete" do
-    s = StringScanner.new("abc")
-    -> {
-      s.clear
-    }.should complain(/clear.*obsolete.*terminate/, verbose: true)
-
-    -> {
-      s.clear
-    }.should_not complain(verbose: false)
-  end
-end
diff --git a/library/stringscanner/empty_spec.rb b/library/stringscanner/empty_spec.rb
deleted file mode 100644
index d9449bea6e..0000000000
--- a/library/stringscanner/empty_spec.rb
+++ /dev/null
@@ -1,18 +0,0 @@
-require_relative '../../spec_helper'
-require_relative 'shared/eos'
-require 'strscan'
-
-describe "StringScanner#empty?" do
-  it_behaves_like :strscan_eos, :empty?
-
-  it "warns in verbose mode that the method is obsolete" do
-    s = StringScanner.new("abc")
-    -> {
-      s.empty?
-    }.should complain(/empty?.*obsolete.*eos?/, verbose: true)
-
-    -> {
-      s.empty?
-    }.should_not complain(verbose: false)
-  end
-end
diff --git a/library/stringscanner/eos_spec.rb b/library/stringscanner/eos_spec.rb
index b58ee1e473..03c2804e5b 100644
--- a/library/stringscanner/eos_spec.rb
+++ b/library/stringscanner/eos_spec.rb
@@ -1,7 +1,20 @@
 require_relative '../../spec_helper'
-require_relative 'shared/eos'
 require 'strscan'
 
 describe "StringScanner#eos?" do
-  it_behaves_like :strscan_eos, :eos?
+  before :each do
+    @s = StringScanner.new("This is a test")
+  end
+
+  it "returns true if the scan pointer is at the end of the string" do
+    @s.terminate
+    @s.should.eos?
+
+    s = StringScanner.new('')
+    s.should.eos?
+  end
+
+  it "returns false if the scan pointer is not at the end of the string" do
+    @s.should_not.eos?
+  end
 end
diff --git a/library/stringscanner/get_byte_spec.rb b/library/stringscanner/get_byte_spec.rb
index 29e2f557de..b3c2b7f678 100644
--- a/library/stringscanner/get_byte_spec.rb
+++ b/library/stringscanner/get_byte_spec.rb
@@ -1,7 +1,88 @@
+# encoding: binary
 require_relative '../../spec_helper'
-require_relative 'shared/get_byte'
 require 'strscan'
 
 describe "StringScanner#get_byte" do
-  it_behaves_like :strscan_get_byte, :get_byte
+  it "scans one byte and returns it" do
+    s = StringScanner.new('abc5.')
+    s.get_byte.should == 'a'
+    s.get_byte.should == 'b'
+    s.get_byte.should == 'c'
+    s.get_byte.should == '5'
+    s.get_byte.should == '.'
+  end
+
+  it "is not multi-byte character sensitive" do
+    s = StringScanner.new("\244\242")
+    s.get_byte.should == "\244"
+    s.get_byte.should == "\242"
+  end
+
+  it "returns nil at the end of the string" do
+    # empty string case
+    s = StringScanner.new('')
+    s.get_byte.should == nil
+    s.get_byte.should == nil
+
+    # non-empty string case
+    s = StringScanner.new('a')
+    s.get_byte # skip one
+    s.get_byte.should == nil
+  end
+
+  describe "#[] successive call with a capture group name" do
+    # https://github.com/ruby/strscan/issues/139
+    ruby_version_is ""..."3.5" do # Don't run on 3.5.0dev that already contains not released fixes
+    version_is StringScanner::Version, "3.1.1"..."3.1.3" do # ruby_version_is "3.4.0"..."3.4.3"
+      it "returns nil" do
+        s = StringScanner.new("This is a test")
+        s.get_byte
+        s.should.matched?
+        s[:a].should be_nil
+      end
+    end
+    end
+    version_is StringScanner::Version, "3.1.3" do # ruby_version_is "3.4.3"
+      it "raises IndexError" do
+        s = StringScanner.new("This is a test")
+        s.get_byte
+        s.should.matched?
+        -> { s[:a] }.should raise_error(IndexError)
+      end
+    end
+
+    it "returns a matching character when given Integer index" do
+      s = StringScanner.new("This is a test")
+      s.get_byte
+      s[0].should == "T"
+    end
+
+    # https://github.com/ruby/strscan/issues/135
+    ruby_version_is ""..."3.5" do # Don't run on 3.5.0dev that already contains not released fixes
+    version_is StringScanner::Version, "3.1.1"..."3.1.3" do # ruby_version_is "3.4.0"..."3.4.3"
+      it "ignores the previous matching with Regexp" do
+        s = StringScanner.new("This is a test")
+        s.exist?(/(?<a>This)/)
+        s.should.matched?
+        s[:a].should == "This"
+
+        s.get_byte
+        s.should.matched?
+        s[:a].should be_nil
+      end
+    end
+    end
+    version_is StringScanner::Version, "3.1.3" do # ruby_version_is "3.4.3"
+      it "ignores the previous matching with Regexp" do
+        s = StringScanner.new("This is a test")
+        s.exist?(/(?<a>This)/)
+        s.should.matched?
+        s[:a].should == "This"
+
+        s.get_byte
+        s.should.matched?
+        -> { s[:a] }.should raise_error(IndexError)
+      end
+    end
+  end
 end
diff --git a/library/stringscanner/getbyte_spec.rb b/library/stringscanner/getbyte_spec.rb
deleted file mode 100644
index e0659a5829..0000000000
--- a/library/stringscanner/getbyte_spec.rb
+++ /dev/null
@@ -1,21 +0,0 @@
-require_relative '../../spec_helper'
-require_relative 'shared/get_byte'
-require_relative 'shared/extract_range'
-require 'strscan'
-
-describe "StringScanner#getbyte" do
-  it_behaves_like :strscan_get_byte, :getbyte
-
-  it "warns in verbose mode that the method is obsolete" do
-    s = StringScanner.new("abc")
-    -> {
-      s.getbyte
-    }.should complain(/getbyte.*obsolete.*get_byte/, verbose: true)
-
-    -> {
-      s.getbyte
-    }.should_not complain(verbose: false)
-  end
-
-  it_behaves_like :extract_range, :getbyte
-end
diff --git a/library/stringscanner/peek_spec.rb b/library/stringscanner/peek_spec.rb
index cbb5630ff9..d490abecf9 100644
--- a/library/stringscanner/peek_spec.rb
+++ b/library/stringscanner/peek_spec.rb
@@ -1,7 +1,42 @@
 require_relative '../../spec_helper'
-require_relative 'shared/peek'
 require 'strscan'
 
 describe "StringScanner#peek" do
-  it_behaves_like :strscan_peek, :peek
+  before :each do
+    @s = StringScanner.new('This is a test')
+  end
+
+  it "returns at most the specified number of bytes from the current position" do
+    @s.peek(4).should == "This"
+    @s.pos.should == 0
+    @s.pos = 5
+    @s.peek(2).should == "is"
+    @s.peek(1000).should == "is a test"
+
+    s = StringScanner.new("été")
+    s.peek(2).should == "é"
+  end
+
+  it "returns an empty string when the passed argument is zero" do
+    @s.peek(0).should == ""
+  end
+
+  it "raises a ArgumentError when the passed argument is negative" do
+    -> { @s.peek(-2) }.should raise_error(ArgumentError)
+  end
+
+  it "raises a RangeError when the passed argument is a Bignum" do
+    -> { @s.peek(bignum_value) }.should raise_error(RangeError)
+  end
+
+  it "returns an instance of String when passed a String subclass" do
+    cls = Class.new(String)
+    sub = cls.new("abc")
+
+    s = StringScanner.new(sub)
+
+    ch = s.peek(1)
+    ch.should_not be_kind_of(cls)
+    ch.should be_an_instance_of(String)
+  end
 end
diff --git a/library/stringscanner/peep_spec.rb b/library/stringscanner/peep_spec.rb
deleted file mode 100644
index bf6d579325..0000000000
--- a/library/stringscanner/peep_spec.rb
+++ /dev/null
@@ -1,18 +0,0 @@
-require_relative '../../spec_helper'
-require_relative 'shared/peek'
-require 'strscan'
-
-describe "StringScanner#peep" do
-  it_behaves_like :strscan_peek, :peep
-
-  it "warns in verbose mode that the method is obsolete" do
-    s = StringScanner.new("abc")
-    -> {
-      s.peep(1)
-    }.should complain(/peep.*obsolete.*peek/, verbose: true)
-
-    -> {
-      s.peep(1)
-    }.should_not complain(verbose: false)
-  end
-end
diff --git a/library/stringscanner/rest_size_spec.rb b/library/stringscanner/rest_size_spec.rb
index e62e3a8f8c..a5e971631a 100644
--- a/library/stringscanner/rest_size_spec.rb
+++ b/library/stringscanner/rest_size_spec.rb
@@ -1,7 +1,21 @@
 require_relative '../../spec_helper'
-require_relative 'shared/rest_size'
 require 'strscan'
 
 describe "StringScanner#rest_size" do
-  it_behaves_like :strscan_rest_size, :rest_size
+  before :each do
+    @s = StringScanner.new('This is a test')
+  end
+
+  it "returns the length of the rest of the string" do
+    @s.rest_size.should == 14
+    @s.scan(/This/)
+    @s.rest_size.should == 10
+    @s.terminate
+    @s.rest_size.should == 0
+  end
+
+  it "is equivalent to rest.size" do
+    @s.scan(/This/)
+    @s.rest_size.should == @s.rest.size
+  end
 end
diff --git a/library/stringscanner/restsize_spec.rb b/library/stringscanner/restsize_spec.rb
deleted file mode 100644
index 710520afae..0000000000
--- a/library/stringscanner/restsize_spec.rb
+++ /dev/null
@@ -1,18 +0,0 @@
-require_relative '../../spec_helper'
-require_relative 'shared/rest_size'
-require 'strscan'
-
-describe "StringScanner#restsize" do
-  it_behaves_like :strscan_rest_size, :restsize
-
-  it "warns in verbose mode that the method is obsolete" do
-    s = StringScanner.new("abc")
-    -> {
-      s.restsize
-    }.should complain(/restsize.*obsolete.*rest_size/, verbose: true)
-
-    -> {
-      s.restsize
-    }.should_not complain(verbose: false)
-  end
-end
diff --git a/library/stringscanner/shared/eos.rb b/library/stringscanner/shared/eos.rb
deleted file mode 100644
index ea04c764a2..0000000000
--- a/library/stringscanner/shared/eos.rb
+++ /dev/null
@@ -1,17 +0,0 @@
-describe :strscan_eos, shared: true do
-  before :each do
-    @s = StringScanner.new("This is a test")
-  end
-
-  it "returns true if the scan pointer is at the end of the string" do
-    @s.terminate
-    @s.send(@method).should be_true
-
-    s = StringScanner.new('')
-    s.send(@method).should be_true
-  end
-
-  it "returns false if the scan pointer is not at the end of the string" do
-    @s.send(@method).should be_false
-  end
-end
diff --git a/library/stringscanner/shared/get_byte.rb b/library/stringscanner/shared/get_byte.rb
deleted file mode 100644
index 1f7378d5c6..0000000000
--- a/library/stringscanner/shared/get_byte.rb
+++ /dev/null
@@ -1,87 +0,0 @@
-# encoding: binary
-require 'strscan'
-
-describe :strscan_get_byte, shared: true do
-  it "scans one byte and returns it" do
-    s = StringScanner.new('abc5.')
-    s.send(@method).should == 'a'
-    s.send(@method).should == 'b'
-    s.send(@method).should == 'c'
-    s.send(@method).should == '5'
-    s.send(@method).should == '.'
-  end
-
-  it "is not multi-byte character sensitive" do
-    s = StringScanner.new("\244\242")
-    s.send(@method).should == "\244"
-    s.send(@method).should == "\242"
-  end
-
-  it "returns nil at the end of the string" do
-    # empty string case
-    s = StringScanner.new('')
-    s.send(@method).should == nil
-    s.send(@method).should == nil
-
-    # non-empty string case
-    s = StringScanner.new('a')
-    s.send(@method) # skip one
-    s.send(@method).should == nil
-  end
-
-  describe "#[] successive call with a capture group name" do
-    # https://github.com/ruby/strscan/issues/139
-    ruby_version_is ""..."3.5" do # Don't run on 3.5.0dev that already contains not released fixes
-    version_is StringScanner::Version, "3.1.1"..."3.1.3" do # ruby_version_is "3.4.0"..."3.4.3"
-      it "returns nil" do
-        s = StringScanner.new("This is a test")
-        s.send(@method)
-        s.should.matched?
-        s[:a].should be_nil
-      end
-    end
-    end
-    version_is StringScanner::Version, "3.1.3" do # ruby_version_is "3.4.3"
-      it "raises IndexError" do
-        s = StringScanner.new("This is a test")
-        s.send(@method)
-        s.should.matched?
-        -> { s[:a] }.should raise_error(IndexError)
-      end
-    end
-
-    it "returns a matching character when given Integer index" do
-      s = StringScanner.new("This is a test")
-      s.send(@method)
-      s[0].should == "T"
-    end
-
-    # https://github.com/ruby/strscan/issues/135
-    ruby_version_is ""..."3.5" do # Don't run on 3.5.0dev that already contains not released fixes
-    version_is StringScanner::Version, "3.1.1"..."3.1.3" do # ruby_version_is "3.4.0"..."3.4.3"
-      it "ignores the previous matching with Regexp" do
-        s = StringScanner.new("This is a test")
-        s.exist?(/(?<a>This)/)
-        s.should.matched?
-        s[:a].should == "This"
-
-        s.send(@method)
-        s.should.matched?
-        s[:a].should be_nil
-      end
-    end
-    end
-    version_is StringScanner::Version, "3.1.3" do # ruby_version_is "3.4.3"
-      it "ignores the previous matching with Regexp" do
-        s = StringScanner.new("This is a test")
-        s.exist?(/(?<a>This)/)
-        s.should.matched?
-        s[:a].should == "This"
-
-        s.send(@method)
-        s.should.matched?
-        -> { s[:a] }.should raise_error(IndexError)
-      end
-    end
-  end
-end
diff --git a/library/stringscanner/shared/peek.rb b/library/stringscanner/shared/peek.rb
deleted file mode 100644
index 4c757866c1..0000000000
--- a/library/stringscanner/shared/peek.rb
+++ /dev/null
@@ -1,39 +0,0 @@
-describe :strscan_peek, shared: true do
-  before :each do
-    @s = StringScanner.new('This is a test')
-  end
-
-  it "returns at most the specified number of bytes from the current position" do
-    @s.send(@method, 4).should == "This"
-    @s.pos.should == 0
-    @s.pos = 5
-    @s.send(@method, 2).should == "is"
-    @s.send(@method, 1000).should == "is a test"
-
-    s = StringScanner.new("été")
-    s.send(@method, 2).should == "é"
-  end
-
-  it "returns an empty string when the passed argument is zero" do
-    @s.send(@method, 0).should == ""
-  end
-
-  it "raises a ArgumentError when the passed argument is negative" do
-    -> { @s.send(@method, -2) }.should raise_error(ArgumentError)
-  end
-
-  it "raises a RangeError when the passed argument is a Bignum" do
-    -> { @s.send(@method, bignum_value) }.should raise_error(RangeError)
-  end
-
-  it "returns an instance of String when passed a String subclass" do
-    cls = Class.new(String)
-    sub = cls.new("abc")
-
-    s = StringScanner.new(sub)
-
-    ch = s.send(@method, 1)
-    ch.should_not be_kind_of(cls)
-    ch.should be_an_instance_of(String)
-  end
-end
diff --git a/library/stringscanner/shared/rest_size.rb b/library/stringscanner/shared/rest_size.rb
deleted file mode 100644
index 4c4f49e45c..0000000000
--- a/library/stringscanner/shared/rest_size.rb
+++ /dev/null
@@ -1,18 +0,0 @@
-describe :strscan_rest_size, shared: true do
-  before :each do
-    @s = StringScanner.new('This is a test')
-  end
-
-  it "returns the length of the rest of the string" do
-    @s.send(@method).should == 14
-    @s.scan(/This/)
-    @s.send(@method).should == 10
-    @s.terminate
-    @s.send(@method).should == 0
-  end
-
-  it "is equivalent to rest.size" do
-    @s.scan(/This/)
-    @s.send(@method).should == @s.rest.size
-  end
-end
diff --git a/library/stringscanner/shared/terminate.rb b/library/stringscanner/shared/terminate.rb
deleted file mode 100644
index bf41d097e2..0000000000
--- a/library/stringscanner/shared/terminate.rb
+++ /dev/null
@@ -1,8 +0,0 @@
-describe :strscan_terminate, shared: true do
-  it "set the scan pointer to the end of the string and clear matching data." do
-    s = StringScanner.new('This is a test')
-    s.send(@method)
-    s.bol?.should be_false
-    s.eos?.should be_true
-  end
-end
diff --git a/library/stringscanner/terminate_spec.rb b/library/stringscanner/terminate_spec.rb
index 7943efe0f9..3cff5c010c 100644
--- a/library/stringscanner/terminate_spec.rb
+++ b/library/stringscanner/terminate_spec.rb
@@ -1,7 +1,11 @@
 require_relative '../../spec_helper'
-require_relative 'shared/terminate'
 require 'strscan'
 
 describe "StringScanner#terminate" do
-  it_behaves_like :strscan_terminate, :terminate
+  it "set the scan pointer to the end of the string and clear matching data." do
+    s = StringScanner.new('This is a test')
+    s.terminate
+    s.should_not.bol?
+    s.should.eos?
+  end
 end
diff --git a/library/stringscanner/unscan_spec.rb b/library/stringscanner/unscan_spec.rb
index df0ea43367..b7b4876b8a 100644
--- a/library/stringscanner/unscan_spec.rb
+++ b/library/stringscanner/unscan_spec.rb
@@ -21,8 +21,8 @@
     @s.pos.should == pos
   end
 
-  it "raises a ScanError when the previous match had failed" do
-    -> { @s.unscan }.should raise_error(ScanError)
-    -> { @s.scan(/\d/); @s.unscan }.should raise_error(ScanError)
+  it "raises a StringScanner::Error when the previous match had failed" do
+    -> { @s.unscan }.should raise_error(StringScanner::Error)
+    -> { @s.scan(/\d/); @s.unscan }.should raise_error(StringScanner::Error)
   end
 end