diff --git a/Gemfile b/Gemfile
index d7ea765b5..fd6c43127 100644
--- a/Gemfile
+++ b/Gemfile
@@ -36,6 +36,9 @@ gem 'rqrcode'
 gem "html-pipeline", "~> 2.13.2"
 gem "sanitize", "~> 6.0"
 
+gem "commonmarker", '~> 2.3.0'
+gem 'deckar01-task_list', '2.3.2'
+
 # Optional gem for LDAP authentication
 group :ldap do
   gem 'net-ldap', '~> 0.17.0'
@@ -46,12 +49,6 @@ group :minimagick do
   gem 'mini_magick', '~> 5.2.0'
 end
 
-# Optional CommonMark support, not for JRuby
-group :common_mark do
-  gem "commonmarker", '~> 2.3.0'
-  gem 'deckar01-task_list', '2.3.2'
-end
-
 # Include database gems for the adapters found in the database
 # configuration file
 database_file = File.join(File.dirname(__FILE__), "config/database.yml")
diff --git a/lib/redmine.rb b/lib/redmine.rb
index 95b3b7f3f..78a1a6d8c 100644
--- a/lib/redmine.rb
+++ b/lib/redmine.rb
@@ -24,11 +24,6 @@ begin
 rescue LoadError
   # MiniMagick is not available
 end
-begin
-  require 'commonmarker' unless Object.const_defined?(:Commonmarker)
-rescue LoadError
-  # CommonMarker is not available
-end
 
 module Redmine
 end
diff --git a/lib/redmine/preparation.rb b/lib/redmine/preparation.rb
index 822662e11..a31204904 100644
--- a/lib/redmine/preparation.rb
+++ b/lib/redmine/preparation.rb
@@ -408,9 +408,7 @@ module Redmine
 
       WikiFormatting.map do |format|
         format.register :textile
-        if Object.const_defined?(:Commonmarker)
-          format.register :common_mark, label: 'CommonMark Markdown (GitHub Flavored)'
-        end
+        format.register :common_mark, label: 'CommonMark Markdown (GitHub Flavored)'
       end
 
       ActionView::Template.register_template_handler :rsb, Views::ApiTemplateHandler
diff --git a/test/helpers/application_helper_test.rb b/test/helpers/application_helper_test.rb
index f959744e2..e0653828e 100644
--- a/test/helpers/application_helper_test.rb
+++ b/test/helpers/application_helper_test.rb
@@ -252,8 +252,6 @@ class ApplicationHelperTest < Redmine::HelperTest
   end
 
   def test_attached_images_with_markdown_and_non_ascii_filename
-    skip unless Object.const_defined?(:CommonMarker)
-
     to_test = {
       'CAFÉ.JPG' => 'CAF%C3%89.JPG',
       'crème.jpg' => 'cr%C3%A8me.jpg',
@@ -1658,13 +1656,11 @@ class ApplicationHelperTest < Redmine::HelperTest
     end
   end
 
-  if Object.const_defined?(:Commonmarker)
-    def test_toc_with_markdown_formatting_should_be_parsed
-      with_settings :text_formatting => 'common_mark' do
-        assert_select_in textilizable("{{toc}}\n\n# Heading"), 'ul.toc li', :text => 'Heading'
-        assert_select_in textilizable("{{<toc}}\n\n# Heading"), 'ul.toc.left li', :text => 'Heading'
-        assert_select_in textilizable("{{>toc}}\n\n# Heading"), 'ul.toc.right li', :text => 'Heading'
-      end
+  def test_toc_with_markdown_formatting_should_be_parsed
+    with_settings :text_formatting => 'common_mark' do
+      assert_select_in textilizable("{{toc}}\n\n# Heading"), 'ul.toc li', :text => 'Heading'
+      assert_select_in textilizable("{{<toc}}\n\n# Heading"), 'ul.toc.left li', :text => 'Heading'
+      assert_select_in textilizable("{{>toc}}\n\n# Heading"), 'ul.toc.right li', :text => 'Heading'
     end
   end
 
diff --git a/test/unit/lib/redmine/wiki_formatting/common_mark/application_helper_test.rb b/test/unit/lib/redmine/wiki_formatting/common_mark/application_helper_test.rb
index 4ecc3e62a..d8e937bb1 100644
--- a/test/unit/lib/redmine/wiki_formatting/common_mark/application_helper_test.rb
+++ b/test/unit/lib/redmine/wiki_formatting/common_mark/application_helper_test.rb
@@ -20,63 +20,60 @@
 require_relative '../../../../../test_helper'
 
 class Redmine::WikiFormatting::CommonMark::ApplicationHelperTest < Redmine::HelperTest
-  if Object.const_defined?(:Commonmarker)
+  include ERB::Util
 
-    include ERB::Util
-
-    def setup
-      super
-      set_tmp_attachments_directory
-    end
+  def setup
+    super
+    set_tmp_attachments_directory
+  end
 
-    def test_attached_images_with_markdown_and_non_ascii_filename
-      to_test = {
-        'CAFÉ.JPG' => 'CAF%C3%89.JPG',
-        'crème.jpg' => 'cr%C3%A8me.jpg',
-      }
-      with_settings :text_formatting => 'common_mark' do
-        to_test.each do |filename, result|
-          attachment = Attachment.generate!(:filename => filename)
-          assert_include %(<img src="/attachments/download/#{attachment.id}/#{result}" alt="" loading="lazy">), textilizable("![](#{filename})", :attachments => [attachment])
-        end
+  def test_attached_images_with_markdown_and_non_ascii_filename
+    to_test = {
+      'CAFÉ.JPG' => 'CAF%C3%89.JPG',
+      'crème.jpg' => 'cr%C3%A8me.jpg',
+    }
+    with_settings :text_formatting => 'common_mark' do
+      to_test.each do |filename, result|
+        attachment = Attachment.generate!(:filename => filename)
+        assert_include %(<img src="/attachments/download/#{attachment.id}/#{result}" alt="" loading="lazy">), textilizable("![](#{filename})", :attachments => [attachment])
       end
     end
+  end
 
-    def test_toc_with_markdown_formatting_should_be_parsed
-      with_settings :text_formatting => 'common_mark' do
-        assert_select_in textilizable("{{toc}}\n\n# Heading"), 'ul.toc li', :text => 'Heading'
-        assert_select_in textilizable("{{<toc}}\n\n# Heading"), 'ul.toc.left li', :text => 'Heading'
-        assert_select_in textilizable("{{>toc}}\n\n# Heading"), 'ul.toc.right li', :text => 'Heading'
-      end
+  def test_toc_with_markdown_formatting_should_be_parsed
+    with_settings :text_formatting => 'common_mark' do
+      assert_select_in textilizable("{{toc}}\n\n# Heading"), 'ul.toc li', :text => 'Heading'
+      assert_select_in textilizable("{{<toc}}\n\n# Heading"), 'ul.toc.left li', :text => 'Heading'
+      assert_select_in textilizable("{{>toc}}\n\n# Heading"), 'ul.toc.right li', :text => 'Heading'
     end
+  end
 
-    def test_attached_image_alt_attribute_with_madkrown
-      attachments = Attachment.all
-      with_settings text_formatting: 'common_mark' do
-        # When alt text is set
-        assert_match %r[<img src=".+?" alt="alt text" loading=".+?">],
-          textilizable('![alt text](logo.gif)', attachments: attachments)
+  def test_attached_image_alt_attribute_with_madkrown
+    attachments = Attachment.all
+    with_settings text_formatting: 'common_mark' do
+      # When alt text is set
+      assert_match %r[<img src=".+?" alt="alt text" loading=".+?">],
+        textilizable('![alt text](logo.gif)', attachments: attachments)
 
-        # When alt text is not set
-        assert_match %r[<img src=".+?" title="This is a logo" alt="This is a logo" loading=".+?">],
-          textilizable('![](logo.gif)', attachments: attachments)
+      # When alt text is not set
+      assert_match %r[<img src=".+?" title="This is a logo" alt="This is a logo" loading=".+?">],
+        textilizable('![](logo.gif)', attachments: attachments)
 
-        # When alt text is not set and the attachment has no description
-        assert_match %r[<img src=".+?" alt="" loading=".+?">],
-          textilizable('![](testfile.PNG)', attachments: attachments)
+      # When alt text is not set and the attachment has no description
+      assert_match %r[<img src=".+?" alt="" loading=".+?">],
+        textilizable('![](testfile.PNG)', attachments: attachments)
 
-        # When no matching attachments are found
-        assert_match %r[<img src=".+?" alt="">],
-          textilizable('![](no-match.jpg)', attachments: attachments)
-        assert_match %r[<img src=".+?" alt="alt text">],
-          textilizable('![alt text](no-match.jpg)', attachments: attachments)
+      # When no matching attachments are found
+      assert_match %r[<img src=".+?" alt="">],
+        textilizable('![](no-match.jpg)', attachments: attachments)
+      assert_match %r[<img src=".+?" alt="alt text">],
+        textilizable('![alt text](no-match.jpg)', attachments: attachments)
 
-        # When no attachment is registered
-        assert_match %r[<img src=".+?" alt="">],
-          textilizable('![](logo.gif)', attachments: [])
-        assert_match %r[<img src=".+?" alt="alt text">],
-          textilizable('![alt text](logo.gif)', attachments: [])
-      end
+      # When no attachment is registered
+      assert_match %r[<img src=".+?" alt="">],
+        textilizable('![](logo.gif)', attachments: [])
+      assert_match %r[<img src=".+?" alt="alt text">],
+        textilizable('![alt text](logo.gif)', attachments: [])
     end
   end
 end
diff --git a/test/unit/lib/redmine/wiki_formatting/common_mark/external_links_filter_test.rb b/test/unit/lib/redmine/wiki_formatting/common_mark/external_links_filter_test.rb
index cde6381b8..c777615e4 100644
--- a/test/unit/lib/redmine/wiki_formatting/common_mark/external_links_filter_test.rb
+++ b/test/unit/lib/redmine/wiki_formatting/common_mark/external_links_filter_test.rb
@@ -18,48 +18,45 @@
 # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 
 require_relative '../../../../../test_helper'
+require 'redmine/wiki_formatting/common_mark/external_links_filter'
 
-if Object.const_defined?(:Commonmarker)
-  require 'redmine/wiki_formatting/common_mark/external_links_filter'
-
-  class Redmine::WikiFormatting::CommonMark::ExternalLinksFilterTest < ActiveSupport::TestCase
-    def filter(html)
-      Redmine::WikiFormatting::CommonMark::ExternalLinksFilter.to_html(html, @options)
-    end
+class Redmine::WikiFormatting::CommonMark::ExternalLinksFilterTest < ActiveSupport::TestCase
+  def filter(html)
+    Redmine::WikiFormatting::CommonMark::ExternalLinksFilter.to_html(html, @options)
+  end
 
-    def setup
-      @options = { }
-    end
+  def setup
+    @options = { }
+  end
 
-    def test_external_links_should_have_external_css_class
-      assert_equal %(<a href="http://example.net/" class="external">link</a>), filter(%(<a href="http://example.net/">link</a>))
-    end
+  def test_external_links_should_have_external_css_class
+    assert_equal %(<a href="http://example.net/" class="external">link</a>), filter(%(<a href="http://example.net/">link</a>))
+  end
 
-    def test_locals_links_should_not_have_external_css_class
-      assert_equal %(<a href="/">home</a>), filter(%(<a href="/">home</a>))
-      assert_equal %(<a href="relative">relative</a>), filter(%(<a href="relative">relative</a>))
-      assert_equal %(<a href="#anchor">anchor</a>), filter(%(<a href="#anchor">anchor</a>))
-    end
+  def test_locals_links_should_not_have_external_css_class
+    assert_equal %(<a href="/">home</a>), filter(%(<a href="/">home</a>))
+    assert_equal %(<a href="relative">relative</a>), filter(%(<a href="relative">relative</a>))
+    assert_equal %(<a href="#anchor">anchor</a>), filter(%(<a href="#anchor">anchor</a>))
+  end
 
-    def test_mailto_links_should_have_email_class
-      assert_equal %(<a href="mailto:user@example.org" class="email">user</a>), filter(%(<a href="mailto:user@example.org">user</a>))
-    end
+  def test_mailto_links_should_have_email_class
+    assert_equal %(<a href="mailto:user@example.org" class="email">user</a>), filter(%(<a href="mailto:user@example.org">user</a>))
+  end
 
-    def test_malformed_uri_should_not_cause_exception
-      assert_nothing_raised do
-        filter(%(<a href="http://example.com/foo#bar#">Malformed URI</a>))
-      end
+  def test_malformed_uri_should_not_cause_exception
+    assert_nothing_raised do
+      filter(%(<a href="http://example.com/foo#bar#">Malformed URI</a>))
     end
+  end
 
-    def test_external_links_with_target_get_rel_noopener
-      assert_equal(
-        %(<a target="_blank" href="http://example.net/" class="external" rel="noopener">link</a>),
-        filter(%(<a target="_blank" href="http://example.net/">link</a>))
-      )
-      assert_equal(
-        %(<a target="_blank" href="http://example.net/" rel="nofollow noopener" class="external">link</a>),
-        filter(%(<a target="_blank" href="http://example.net/" rel="nofollow">link</a>))
-      )
-    end
+  def test_external_links_with_target_get_rel_noopener
+    assert_equal(
+      %(<a target="_blank" href="http://example.net/" class="external" rel="noopener">link</a>),
+      filter(%(<a target="_blank" href="http://example.net/">link</a>))
+    )
+    assert_equal(
+      %(<a target="_blank" href="http://example.net/" rel="nofollow noopener" class="external">link</a>),
+      filter(%(<a target="_blank" href="http://example.net/" rel="nofollow">link</a>))
+    )
   end
 end
diff --git a/test/unit/lib/redmine/wiki_formatting/common_mark/fixup_auto_links_filter_test.rb b/test/unit/lib/redmine/wiki_formatting/common_mark/fixup_auto_links_filter_test.rb
index 1b093d718..6a45c64bc 100644
--- a/test/unit/lib/redmine/wiki_formatting/common_mark/fixup_auto_links_filter_test.rb
+++ b/test/unit/lib/redmine/wiki_formatting/common_mark/fixup_auto_links_filter_test.rb
@@ -18,33 +18,30 @@
 # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 
 require_relative '../../../../../test_helper'
+require 'redmine/wiki_formatting/common_mark/fixup_auto_links_filter'
 
-if Object.const_defined?(:Commonmarker)
-  require 'redmine/wiki_formatting/common_mark/fixup_auto_links_filter'
-
-  class Redmine::WikiFormatting::CommonMark::FixupAutoLinksFilterTest < ActiveSupport::TestCase
-    def filter(html)
-      Redmine::WikiFormatting::CommonMark::FixupAutoLinksFilter.to_html(html, @options)
-    end
+class Redmine::WikiFormatting::CommonMark::FixupAutoLinksFilterTest < ActiveSupport::TestCase
+  def filter(html)
+    Redmine::WikiFormatting::CommonMark::FixupAutoLinksFilter.to_html(html, @options)
+  end
 
-    def format(markdown)
-      Redmine::WikiFormatting::CommonMark::MarkdownFilter.to_html(markdown, Redmine::WikiFormatting::CommonMark::PIPELINE_CONFIG)
-    end
+  def format(markdown)
+    Redmine::WikiFormatting::CommonMark::MarkdownFilter.to_html(markdown, Redmine::WikiFormatting::CommonMark::PIPELINE_CONFIG)
+  end
 
-    def setup
-      @options = { }
-    end
+  def setup
+    @options = { }
+  end
 
-    def test_should_fixup_autolinked_user_references
-      text = "user:user@example.org"
-      assert_equal "<p>#{text}</p>", filter(format(text))
-      text = "@user@example.org"
-      assert_equal "<p>#{text}</p>", filter(format(text))
-    end
+  def test_should_fixup_autolinked_user_references
+    text = "user:user@example.org"
+    assert_equal "<p>#{text}</p>", filter(format(text))
+    text = "@user@example.org"
+    assert_equal "<p>#{text}</p>", filter(format(text))
+  end
 
-    def test_should_fixup_autolinked_hires_files
-      text = "printscreen@2x.png"
-      assert_equal "<p>#{text}</p>", filter(format(text))
-    end
+  def test_should_fixup_autolinked_hires_files
+    text = "printscreen@2x.png"
+    assert_equal "<p>#{text}</p>", filter(format(text))
   end
 end
diff --git a/test/unit/lib/redmine/wiki_formatting/common_mark/formatter_test.rb b/test/unit/lib/redmine/wiki_formatting/common_mark/formatter_test.rb
index 11d5913ce..bd0b6fe38 100644
--- a/test/unit/lib/redmine/wiki_formatting/common_mark/formatter_test.rb
+++ b/test/unit/lib/redmine/wiki_formatting/common_mark/formatter_test.rb
@@ -20,294 +20,291 @@
 require_relative '../../../../../test_helper'
 
 class Redmine::WikiFormatting::CommonMark::FormatterTest < ActionView::TestCase
-  if Object.const_defined?(:Commonmarker)
-
-    def setup
-      @formatter = Redmine::WikiFormatting::CommonMark::Formatter
-    end
+  def setup
+    @formatter = Redmine::WikiFormatting::CommonMark::Formatter
+  end
 
-    def to_html(text)
-      @formatter.new(text).to_html
-    end
+  def to_html(text)
+    @formatter.new(text).to_html
+  end
 
-    def test_should_render_hard_breaks
-      html ="<p>foo<br>\nbar</p>"
-      assert_equal html, to_html("foo\\\nbar")
-      assert_equal html, to_html("foo  \nbar")
-    end
+  def test_should_render_hard_breaks
+    html ="<p>foo<br>\nbar</p>"
+    assert_equal html, to_html("foo\\\nbar")
+    assert_equal html, to_html("foo  \nbar")
+  end
 
-    def test_should_render_soft_breaks
-      assert_equal "<p>foo<br>\nbar</p>", to_html("foo\nbar")
-    end
+  def test_should_render_soft_breaks
+    assert_equal "<p>foo<br>\nbar</p>", to_html("foo\nbar")
+  end
 
-    def test_syntax_error_in_image_reference_should_not_raise_exception
-      assert to_html("!>[](foo.png)")
-    end
+  def test_syntax_error_in_image_reference_should_not_raise_exception
+    assert to_html("!>[](foo.png)")
+  end
 
-    def test_empty_image_should_not_raise_exception
-      assert to_html("![]()")
-    end
+  def test_empty_image_should_not_raise_exception
+    assert to_html("![]()")
+  end
 
-    def test_inline_style
-      assert_equal "<p><strong>foo</strong></p>", to_html("**foo**")
-    end
+  def test_inline_style
+    assert_equal "<p><strong>foo</strong></p>", to_html("**foo**")
+  end
 
-    def test_not_set_intra_emphasis
-      assert_equal "<p>foo_bar_baz</p>", to_html("foo_bar_baz")
-    end
+  def test_not_set_intra_emphasis
+    assert_equal "<p>foo_bar_baz</p>", to_html("foo_bar_baz")
+  end
 
-    def test_wiki_links_should_be_preserved
-      text = 'This is a wiki link: [[Foo]]'
-      assert_include '[[Foo]]', to_html(text)
-    end
+  def test_wiki_links_should_be_preserved
+    text = 'This is a wiki link: [[Foo]]'
+    assert_include '[[Foo]]', to_html(text)
+  end
 
-    def test_redmine_links_with_double_quotes_should_be_preserved
-      text = 'This is a redmine link: version:"1.0"'
-      assert_include 'version:"1.0"', to_html(text)
-    end
+  def test_redmine_links_with_double_quotes_should_be_preserved
+    text = 'This is a redmine link: version:"1.0"'
+    assert_include 'version:"1.0"', to_html(text)
+  end
 
-    def test_links_by_id_should_be_preserved
-      text = "[project#3]"
-      assert_equal "<p>#{text}</p>", to_html(text)
-    end
+  def test_links_by_id_should_be_preserved
+    text = "[project#3]"
+    assert_equal "<p>#{text}</p>", to_html(text)
+  end
 
-    def test_links_to_users_should_be_preserved
-      text = "[@login]"
-      assert_equal "<p>#{text}</p>", to_html(text)
-      text = "[user:login]"
-      assert_equal "<p>#{text}</p>", to_html(text)
-      text = "user:user@example.org"
-      assert_equal "<p>#{text}</p>", to_html(text)
-      text = "[user:user@example.org]"
-      assert_equal "<p>#{text}</p>", to_html(text)
-      text = "@user@example.org"
-      assert_equal "<p>#{text}</p>", to_html(text)
-      text = "[@user@example.org]"
-      assert_equal "<p>#{text}</p>", to_html(text)
-    end
+  def test_links_to_users_should_be_preserved
+    text = "[@login]"
+    assert_equal "<p>#{text}</p>", to_html(text)
+    text = "[user:login]"
+    assert_equal "<p>#{text}</p>", to_html(text)
+    text = "user:user@example.org"
+    assert_equal "<p>#{text}</p>", to_html(text)
+    text = "[user:user@example.org]"
+    assert_equal "<p>#{text}</p>", to_html(text)
+    text = "@user@example.org"
+    assert_equal "<p>#{text}</p>", to_html(text)
+    text = "[@user@example.org]"
+    assert_equal "<p>#{text}</p>", to_html(text)
+  end
 
-    def test_files_with_at_should_not_end_up_as_mailto_links
-      text = "printscreen@2x.png"
-      assert_equal "<p>#{text}</p>", to_html(text)
-      text = "[printscreen@2x.png]"
-      assert_equal "<p>#{text}</p>", to_html(text)
-    end
+  def test_files_with_at_should_not_end_up_as_mailto_links
+    text = "printscreen@2x.png"
+    assert_equal "<p>#{text}</p>", to_html(text)
+    text = "[printscreen@2x.png]"
+    assert_equal "<p>#{text}</p>", to_html(text)
+  end
 
-    def test_should_support_syntax_highlight
-      text = <<~STR
-        ~~~ruby
-        def foo
-        end
-        ~~~
-      STR
-      assert_select_in to_html(text), 'pre code.ruby.syntaxhl' do
-        assert_select 'span.k', :text => 'def'
-        assert_select "[data-language='ruby']"
+  def test_should_support_syntax_highlight
+    text = <<~STR
+      ~~~ruby
+      def foo
       end
+      ~~~
+    STR
+    assert_select_in to_html(text), 'pre code.ruby.syntaxhl' do
+      assert_select 'span.k', :text => 'def'
+      assert_select "[data-language='ruby']"
     end
+  end
 
-    def test_should_support_syntax_highlight_for_language_with_special_chars
-      text = <<~STR
-        ~~~c++
-        int main() {
-        }
-        ~~~
-      STR
-
-      assert_select_in to_html(text), 'pre' do
-        assert_select 'code[class=?]', "c++ syntaxhl"
-        assert_select 'span.kt', :text => 'int'
-        assert_select "[data-language=?]", "c++"
-      end
+  def test_should_support_syntax_highlight_for_language_with_special_chars
+    text = <<~STR
+      ~~~c++
+      int main() {
+      }
+      ~~~
+    STR
+
+    assert_select_in to_html(text), 'pre' do
+      assert_select 'code[class=?]', "c++ syntaxhl"
+      assert_select 'span.kt', :text => 'int'
+      assert_select "[data-language=?]", "c++"
     end
+  end
 
-    def test_external_links_should_have_external_css_class
-      text = 'This is a [link](http://example.net/)'
-      assert_equal '<p>This is a <a href="http://example.net/" class="external">link</a></p>', to_html(text)
-    end
+  def test_external_links_should_have_external_css_class
+    text = 'This is a [link](http://example.net/)'
+    assert_equal '<p>This is a <a href="http://example.net/" class="external">link</a></p>', to_html(text)
+  end
 
-    def test_locals_links_should_not_have_external_css_class
-      text = 'This is a [link](/issues)'
-      assert_equal '<p>This is a <a href="/issues">link</a></p>', to_html(text)
-    end
+  def test_locals_links_should_not_have_external_css_class
+    text = 'This is a [link](/issues)'
+    assert_equal '<p>This is a <a href="/issues">link</a></p>', to_html(text)
+  end
 
-    def test_markdown_should_not_require_surrounded_empty_line
-      text = <<-STR
-  This is a list:
-  * One
-  * Two
-      STR
-      assert_equal "<p>This is a list:</p>\n<ul>\n<li>One</li>\n<li>Two</li>\n</ul>", to_html(text)
-    end
+  def test_markdown_should_not_require_surrounded_empty_line
+    text = <<~STR
+      This is a list:
+      * One
+      * Two
+    STR
+    assert_equal "<p>This is a list:</p>\n<ul>\n<li>One</li>\n<li>Two</li>\n</ul>", to_html(text)
+  end
 
-    def test_footnotes
-      text = <<~STR
-        This is some text[^1].
+  def test_footnotes
+    text = <<~STR
+      This is some text[^1].
 
-        [^1]: This is the foot note
-      STR
+      [^1]: This is the foot note
+    STR
 
-      expected = <<~EXPECTED
-        <p>This is some text<sup><a href="#fn-1" id="fnref-1">1</a></sup>.</p>
-         <ol>
-        <li id="fn-1">
-        <p>This is the foot note <a href="#fnref-1" aria-label="Back to reference 1">↩</a></p>
-        </li>
-        </ol>
-      EXPECTED
+    expected = <<~EXPECTED
+      <p>This is some text<sup><a href="#fn-1" id="fnref-1">1</a></sup>.</p>
+       <ol>
+      <li id="fn-1">
+      <p>This is the foot note <a href="#fnref-1" aria-label="Back to reference 1">↩</a></p>
+      </li>
+      </ol>
+    EXPECTED
 
-      assert_equal expected.gsub(%r{[\r\n\t]}, ''), to_html(text).gsub(%r{[\r\n\t]}, '').rstrip
-    end
+    assert_equal expected.gsub(%r{[\r\n\t]}, ''), to_html(text).gsub(%r{[\r\n\t]}, '').rstrip
+  end
+
+  STR_WITH_PRE = [
+    # 0
+    <<~STR.chomp,
+      # Title
 
-    STR_WITH_PRE = [
-      # 0
-      <<~STR.chomp,
-        # Title
-  
-        Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Maecenas sed libero.
-      STR
-      # 1
-      <<~STR.chomp,
-        ## Heading 2
-  
-        ~~~ruby
-          def foo
-          end
-        ~~~
-  
-        Morbi facilisis accumsan orci non pharetra.
-  
-        ~~~ ruby
+      Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Maecenas sed libero.
+    STR
+    # 1
+    <<~STR.chomp,
+      ## Heading 2
+
+      ~~~ruby
         def foo
         end
-        ~~~
-  
-        ```
-        Pre Content:
-  
-        ## Inside pre
-  
-        <tag> inside pre block
-  
-        Morbi facilisis accumsan orci non pharetra.
-        ```
-      STR
-      # 2
-      <<~STR.chomp,
-        ### Heading 3
-  
-        Nulla nunc nisi, egestas in ornare vel, posuere ac libero.
-      STR
-    ]
-
-    def test_get_section_should_ignore_pre_content
-      text = STR_WITH_PRE.join("\n\n")
-
-      assert_section_with_hash STR_WITH_PRE[1..2].join("\n\n"), text, 2
-      assert_section_with_hash STR_WITH_PRE[2], text, 3
-    end
+      ~~~
 
-    def test_get_section_should_not_recognize_double_hash_issue_reference_as_heading
-      text = <<~STR
-        ## Section A
+      Morbi facilisis accumsan orci non pharetra.
 
-        This text is a part of Section A.
+      ~~~ ruby
+      def foo
+      end
+      ~~~
 
-        ##1 : This is an issue reference, not an ATX heading.
+      ```
+      Pre Content:
 
-        This text is also a part of Section A.
-        <!-- Section A ends here -->
-      STR
+      ## Inside pre
 
-      assert_section_with_hash text.chomp, text, 1
-    end
+      <tag> inside pre block
 
-    def test_update_section_should_not_escape_pre_content_outside_section
-      text = STR_WITH_PRE.join("\n\n")
-      replacement = "New text"
+      Morbi facilisis accumsan orci non pharetra.
+      ```
+    STR
+    # 2
+    <<~STR.chomp,
+      ### Heading 3
 
-      assert_equal [STR_WITH_PRE[0..1], "New text"].flatten.join("\n\n"),
-        @formatter.new(text).update_section(3, replacement)
-    end
+      Nulla nunc nisi, egestas in ornare vel, posuere ac libero.
+    STR
+  ]
 
-    def test_should_emphasize_text
-      text = 'This _text_ should be emphasized'
-      assert_equal '<p>This <em>text</em> should be emphasized</p>', to_html(text)
-    end
+  def test_get_section_should_ignore_pre_content
+    text = STR_WITH_PRE.join("\n\n")
 
-    def test_should_strike_through_text
-      text = 'This ~~text~~ should be striked through'
-      assert_equal '<p>This <del>text</del> should be striked through</p>', to_html(text)
-    end
+    assert_section_with_hash STR_WITH_PRE[1..2].join("\n\n"), text, 2
+    assert_section_with_hash STR_WITH_PRE[2], text, 3
+  end
 
-    def test_should_autolink_urls_and_emails
-      [
-        ["http://example.org", '<p><a href="http://example.org" class="external">http://example.org</a></p>'],
-        ["http://www.redmine.org/projects/redmine/issues?utf8=✓",
-         '<p><a href="http://www.redmine.org/projects/redmine/issues?utf8=%E2%9C%93" class="external">http://www.redmine.org/projects/redmine/issues?utf8=✓</a></p>'],
-        ['[Letters](https://yandex.ru/search/?text=кол-во)', '<p><a href="https://yandex.ru/search/?text=%D0%BA%D0%BE%D0%BB-%D0%B2%D0%BE" class="external">Letters</a></p>'],
-        ["www.example.org", '<p><a href="http://www.example.org" class="external">www.example.org</a></p>'],
-        ["user@example.org", '<p><a href="mailto:user@example.org" class="email">user@example.org</a></p>']
-      ].each do |text, html|
-        assert_equal html, to_html(text)
-      end
-    end
+  def test_get_section_should_not_recognize_double_hash_issue_reference_as_heading
+    text = <<~STR
+      ## Section A
+
+      This text is a part of Section A.
+
+      ##1 : This is an issue reference, not an ATX heading.
+
+      This text is also a part of Section A.
+      <!-- Section A ends here -->
+    STR
+
+    assert_section_with_hash text.chomp, text, 1
+  end
 
-    def test_should_support_html_tables
-      text = '<table style="background: red"><tr><td>Cell</td></tr></table>'
-      assert_equal '<table><tr><td>Cell</td></tr></table>', to_html(text)
+  def test_update_section_should_not_escape_pre_content_outside_section
+    text = STR_WITH_PRE.join("\n\n")
+    replacement = "New text"
+
+    assert_equal [STR_WITH_PRE[0..1], "New text"].flatten.join("\n\n"),
+      @formatter.new(text).update_section(3, replacement)
+  end
+
+  def test_should_emphasize_text
+    text = 'This _text_ should be emphasized'
+    assert_equal '<p>This <em>text</em> should be emphasized</p>', to_html(text)
+  end
+
+  def test_should_strike_through_text
+    text = 'This ~~text~~ should be striked through'
+    assert_equal '<p>This <del>text</del> should be striked through</p>', to_html(text)
+  end
+
+  def test_should_autolink_urls_and_emails
+    [
+      ["http://example.org", '<p><a href="http://example.org" class="external">http://example.org</a></p>'],
+      ["http://www.redmine.org/projects/redmine/issues?utf8=✓",
+       '<p><a href="http://www.redmine.org/projects/redmine/issues?utf8=%E2%9C%93" class="external">http://www.redmine.org/projects/redmine/issues?utf8=✓</a></p>'],
+      ['[Letters](https://yandex.ru/search/?text=кол-во)', '<p><a href="https://yandex.ru/search/?text=%D0%BA%D0%BE%D0%BB-%D0%B2%D0%BE" class="external">Letters</a></p>'],
+      ["www.example.org", '<p><a href="http://www.example.org" class="external">www.example.org</a></p>'],
+      ["user@example.org", '<p><a href="mailto:user@example.org" class="email">user@example.org</a></p>']
+    ].each do |text, html|
+      assert_equal html, to_html(text)
     end
+  end
 
-    def test_should_remove_unsafe_uris
-      [
-        ['<img src="data:foobar">', '<img>'],
-        ['<a href="javascript:bla">click me</a>', '<p><a>click me</a></p>'],
-      ].each do |text, html|
-        assert_equal html, to_html(text)
-      end
+  def test_should_support_html_tables
+    text = '<table style="background: red"><tr><td>Cell</td></tr></table>'
+    assert_equal '<table><tr><td>Cell</td></tr></table>', to_html(text)
+  end
+
+  def test_should_remove_unsafe_uris
+    [
+      ['<img src="data:foobar">', '<img>'],
+      ['<a href="javascript:bla">click me</a>', '<p><a>click me</a></p>'],
+    ].each do |text, html|
+      assert_equal html, to_html(text)
     end
+  end
 
-    def test_should_escape_unwanted_tags
+  def test_should_escape_unwanted_tags
+    [
       [
-        [
-          %[<p>sit<br>amet &lt;style&gt;.foo { color: #fff; }&lt;/style&gt; &lt;script&gt;alert("hello world");&lt;/script&gt;</p>],
-          %[sit<br/>amet <style>.foo { color: #fff; }</style> <script>alert("hello world");</script>]
-        ]
-      ].each do |expected, input|
-        assert_equal expected, to_html(input)
-      end
+        %[<p>sit<br>amet &lt;style&gt;.foo { color: #fff; }&lt;/style&gt; &lt;script&gt;alert("hello world");&lt;/script&gt;</p>],
+        %[sit<br/>amet <style>.foo { color: #fff; }</style> <script>alert("hello world");</script>]
+      ]
+    ].each do |expected, input|
+      assert_equal expected, to_html(input)
     end
+  end
 
-    def test_should_support_task_list
-      text = <<~STR
-        Task list:
-        * [ ] Task 1
-        * [x] Task 2
-      STR
-
-      expected = <<~EXPECTED
-        <p>Task list:</p>
-        <ul class="task-list">
-        <li class="task-list-item">
-        <input type="checkbox" class="task-list-item-checkbox" disabled> Task 1
-        </li>
-        <li class="task-list-item">
-        <input type="checkbox" class="task-list-item-checkbox" checked disabled> Task 2</li>
-        </ul>
-      EXPECTED
-
-      assert_equal expected.gsub(%r{[\r\n\t]}, ''), to_html(text).gsub(%r{[\r\n\t]}, '').rstrip
-    end
+  def test_should_support_task_list
+    text = <<~STR
+      Task list:
+      * [ ] Task 1
+      * [x] Task 2
+    STR
+
+    expected = <<~EXPECTED
+      <p>Task list:</p>
+      <ul class="task-list">
+      <li class="task-list-item">
+      <input type="checkbox" class="task-list-item-checkbox" disabled> Task 1
+      </li>
+      <li class="task-list-item">
+      <input type="checkbox" class="task-list-item-checkbox" checked disabled> Task 2</li>
+      </ul>
+    EXPECTED
+
+    assert_equal expected.gsub(%r{[\r\n\t]}, ''), to_html(text).gsub(%r{[\r\n\t]}, '').rstrip
+  end
 
-    private
+  private
 
-    def assert_section_with_hash(expected, text, index)
-      result = @formatter.new(text).get_section(index)
+  def assert_section_with_hash(expected, text, index)
+    result = @formatter.new(text).get_section(index)
 
-      assert_kind_of Array, result
-      assert_equal 2, result.size
-      assert_equal expected, result.first, "section content did not match"
-      assert_equal ActiveSupport::Digest.hexdigest(expected), result.last, "section hash did not match"
-    end
+    assert_kind_of Array, result
+    assert_equal 2, result.size
+    assert_equal expected, result.first, "section content did not match"
+    assert_equal ActiveSupport::Digest.hexdigest(expected), result.last, "section hash did not match"
   end
 end
diff --git a/test/unit/lib/redmine/wiki_formatting/common_mark/markdown_filter_test.rb b/test/unit/lib/redmine/wiki_formatting/common_mark/markdown_filter_test.rb
index d5e416d2c..28bf40581 100644
--- a/test/unit/lib/redmine/wiki_formatting/common_mark/markdown_filter_test.rb
+++ b/test/unit/lib/redmine/wiki_formatting/common_mark/markdown_filter_test.rb
@@ -18,18 +18,15 @@
 # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 
 require_relative '../../../../../test_helper'
+require 'redmine/wiki_formatting/common_mark/markdown_filter'
 
-if Object.const_defined?(:Commonmarker)
-  require 'redmine/wiki_formatting/common_mark/markdown_filter'
-
-  class Redmine::WikiFormatting::CommonMark::MarkdownFilterTest < ActiveSupport::TestCase
-    def filter(markdown)
-      Redmine::WikiFormatting::CommonMark::MarkdownFilter.to_html(markdown)
-    end
+class Redmine::WikiFormatting::CommonMark::MarkdownFilterTest < ActiveSupport::TestCase
+  def filter(markdown)
+    Redmine::WikiFormatting::CommonMark::MarkdownFilter.to_html(markdown)
+  end
 
-    # just a basic sanity test. more formatting tests in the formatter_test
-    def test_should_render_markdown
-      assert_equal "<p><strong>bold</strong></p>", filter("**bold**")
-    end
+  # just a basic sanity test. more formatting tests in the formatter_test
+  def test_should_render_markdown
+    assert_equal "<p><strong>bold</strong></p>", filter("**bold**")
   end
 end
diff --git a/test/unit/lib/redmine/wiki_formatting/common_mark/sanitization_filter_test.rb b/test/unit/lib/redmine/wiki_formatting/common_mark/sanitization_filter_test.rb
index 4c0282f2d..a934c8176 100644
--- a/test/unit/lib/redmine/wiki_formatting/common_mark/sanitization_filter_test.rb
+++ b/test/unit/lib/redmine/wiki_formatting/common_mark/sanitization_filter_test.rb
@@ -18,216 +18,213 @@
 # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 
 require_relative '../../../../../test_helper'
+require 'redmine/wiki_formatting/common_mark/sanitization_filter'
 
-if Object.const_defined?(:Commonmarker)
-  require 'redmine/wiki_formatting/common_mark/sanitization_filter'
+class Redmine::WikiFormatting::CommonMark::SanitizationFilterTest < ActiveSupport::TestCase
+  def filter(html)
+    Redmine::WikiFormatting::CommonMark::SanitizationFilter.to_html(html, @options)
+  end
 
-  class Redmine::WikiFormatting::CommonMark::SanitizationFilterTest < ActiveSupport::TestCase
-    def filter(html)
-      Redmine::WikiFormatting::CommonMark::SanitizationFilter.to_html(html, @options)
-    end
+  def setup
+    @options = { }
+  end
 
-    def setup
-      @options = { }
-    end
+  def test_should_filter_tags
+    input = %(<textarea>foo</textarea> <blink>dont blink</blink>)
+    assert_equal %(foo dont blink), filter(input)
+  end
 
-    def test_should_filter_tags
-      input = %(<textarea>foo</textarea> <blink>dont blink</blink>)
-      assert_equal %(foo dont blink), filter(input)
-    end
+  def test_should_sanitize_attributes
+    input = %(<a href="foo" onclick="bar" baz="foo">link</a>)
+    assert_equal %(<a href="foo">link</a>), filter(input)
+  end
 
-    def test_should_sanitize_attributes
-      input = %(<a href="foo" onclick="bar" baz="foo">link</a>)
-      assert_equal %(<a href="foo">link</a>), filter(input)
-    end
+  def test_should_allow_relative_links
+    input = %(<a href="foo/bar">foo/bar</a>)
+    assert_equal input, filter(input)
+  end
 
-    def test_should_allow_relative_links
-      input = %(<a href="foo/bar">foo/bar</a>)
-      assert_equal input, filter(input)
-    end
+  def test_should_support_footnotes
+    input = %(<a href="#fn-1" id="fnref-1">foo</a>)
+    assert_equal input, filter(input)
+    input = %(<ol><li id="fn-1">footnote</li></ol>)
+    assert_equal input, filter(input)
+  end
 
-    def test_should_support_footnotes
-      input = %(<a href="#fn-1" id="fnref-1">foo</a>)
-      assert_equal input, filter(input)
-      input = %(<ol><li id="fn-1">footnote</li></ol>)
-      assert_equal input, filter(input)
-    end
+  def test_should_remove_invalid_ids
+    input = %(<a href="#fn1" id="foo">foo</a>)
+    assert_equal %(<a href="#fn1">foo</a>), filter(input)
+    input = %(<ol><li id="foo">footnote</li></ol>)
+    assert_equal %(<ol><li>footnote</li></ol>), filter(input)
+  end
 
-    def test_should_remove_invalid_ids
-      input = %(<a href="#fn1" id="foo">foo</a>)
-      assert_equal %(<a href="#fn1">foo</a>), filter(input)
-      input = %(<ol><li id="foo">footnote</li></ol>)
-      assert_equal %(<ol><li>footnote</li></ol>), filter(input)
-    end
+  def test_should_allow_class_on_code_only
+    input = %(<p class="foo">bar</p>)
+    assert_equal %(<p>bar</p>), filter(input)
 
-    def test_should_allow_class_on_code_only
-      input = %(<p class="foo">bar</p>)
-      assert_equal %(<p>bar</p>), filter(input)
+    input = %(<code class="language-ruby">foo</code>)
+    assert_equal input, filter(input)
 
-      input = %(<code class="language-ruby">foo</code>)
-      assert_equal input, filter(input)
+    input = %(<code class="foo">foo</code>)
+    assert_equal %(<code>foo</code>), filter(input)
+  end
 
-      input = %(<code class="foo">foo</code>)
-      assert_equal %(<code>foo</code>), filter(input)
+  def test_should_allow_links_with_safe_url_schemes
+    %w(http https ftp ssh foo).each do |scheme|
+      input = %(<a href="#{scheme}://example.org/">foo</a>)
+      assert_equal input, filter(input)
     end
+  end
 
-    def test_should_allow_links_with_safe_url_schemes
-      %w(http https ftp ssh foo).each do |scheme|
-        input = %(<a href="#{scheme}://example.org/">foo</a>)
-        assert_equal input, filter(input)
-      end
-    end
+  def test_should_allow_mailto_links
+    input = %(<a href="mailto:foo@example.org">bar</a>)
+    assert_equal input, filter(input)
+  end
 
-    def test_should_allow_mailto_links
-      input = %(<a href="mailto:foo@example.org">bar</a>)
-      assert_equal input, filter(input)
-    end
+  def test_should_remove_empty_link
+    input = %(<a href="">bar</a>)
+    assert_equal %(<a>bar</a>), filter(input)
+    input = %(<a href=" ">bar</a>)
+    assert_equal %(<a>bar</a>), filter(input)
+  end
+
+  # samples taken from the Sanitize test suite
+  # rubocop:disable Layout/LineLength
+  STRINGS = [
+    [
+      '<span style="color: #333; background: url(\'https://example.com/evil.svg\')">hello</span>"',
+      '<span style="color: #333; ">hello</span>"'
+    ],
+    [
+      '<img src="photo.jpg" style="min-width: 100px; max-width: 200px; min-height: 100px; max-height: 200px;">',
+      '<img src="photo.jpg" style="min-width: 100px; max-width: 200px; min-height: 100px; max-height: 200px;">'
+    ],
+    [
+      '<b>Lo<!-- comment -->rem</b> <a href="pants" title="foo" style="text-decoration: underline;">ipsum</a> <a href="http://foo.com/"><strong>dolor</strong></a> sit<br/>amet <style>.foo { color: #fff; }</style> <script>alert("hello world");</script>',
+      '<b>Lorem</b> <a href="pants" title="foo">ipsum</a> <a href="http://foo.com/"><strong>dolor</strong></a> sit<br>amet .foo { color: #fff; } '
+    ],
+    [
+      'Lo<!-- comment -->rem</b> <a href=pants title="foo>ipsum <a href="http://foo.com/"><strong>dolor</a></strong> sit<br/>amet <script>alert("hello world");',
+      'Lorem <a href="pants" title="foo&gt;ipsum &lt;a href="><strong>dolor</strong></a> sit<br>amet '
+    ],
+    [
+      '<p>a</p><blockquote>b',
+      '<p>a</p><blockquote>b</blockquote>'
+    ],
+    [
+      '<b>Lo<!-- comment -->rem</b> <a href="javascript:pants" title="foo">ipsum</a> <a href="http://foo.com/"><strong>dolor</strong></a> sit<br/>amet <<foo>script>alert("hello world");</script>',
+      '<b>Lorem</b> <a title="foo">ipsum</a> <a href="http://foo.com/"><strong>dolor</strong></a> sit<br>amet &lt;script&gt;alert("hello world");'
+    ]
+  ]
+  # rubocop:enable Layout/LineLength
 
-    def test_should_remove_empty_link
-      input = %(<a href="">bar</a>)
-      assert_equal %(<a>bar</a>), filter(input)
-      input = %(<a href=" ">bar</a>)
-      assert_equal %(<a>bar</a>), filter(input)
+  def test_should_sanitize_html_strings
+    STRINGS.each do |input, expected|
+      assert_equal expected, filter(input)
     end
+  end
+
+  # samples taken from the Sanitize test suite
+  PROTOCOLS = {
+    'protocol-based JS injection: simple, no spaces' => [
+      '<a href="javascript:alert(\'XSS\');">foo</a>',
+      '<a>foo</a>'
+    ],
+
+    'protocol-based JS injection: simple, spaces before' => [
+      '<a href="javascript    :alert(\'XSS\');">foo</a>',
+      '<a>foo</a>'
+    ],
+
+    'protocol-based JS injection: simple, spaces after' => [
+      '<a href="javascript:    alert(\'XSS\');">foo</a>',
+      '<a>foo</a>'
+    ],
+
+    'protocol-based JS injection: simple, spaces before and after' => [
+      '<a href="javascript    :   alert(\'XSS\');">foo</a>',
+      '<a>foo</a>'
+    ],
+
+    'protocol-based JS injection: preceding colon' => [
+      '<a href=":javascript:alert(\'XSS\');">foo</a>',
+      '<a>foo</a>'
+    ],
+
+    'protocol-based JS injection: UTF-8 encoding' => [
+      '<a href="javascript&#58;">foo</a>',
+      '<a>foo</a>'
+    ],
+
+    'protocol-based JS injection: long UTF-8 encoding' => [
+      '<a href="javascript&#0058;">foo</a>',
+      '<a>foo</a>'
+    ],
 
-    # samples taken from the Sanitize test suite
     # rubocop:disable Layout/LineLength
-    STRINGS = [
-      [
-        '<span style="color: #333; background: url(\'https://example.com/evil.svg\')">hello</span>"',
-        '<span style="color: #333; ">hello</span>"'
-      ],
-      [
-        '<img src="photo.jpg" style="min-width: 100px; max-width: 200px; min-height: 100px; max-height: 200px;">',
-        '<img src="photo.jpg" style="min-width: 100px; max-width: 200px; min-height: 100px; max-height: 200px;">'
-      ],
-      [
-        '<b>Lo<!-- comment -->rem</b> <a href="pants" title="foo" style="text-decoration: underline;">ipsum</a> <a href="http://foo.com/"><strong>dolor</strong></a> sit<br/>amet <style>.foo { color: #fff; }</style> <script>alert("hello world");</script>',
-        '<b>Lorem</b> <a href="pants" title="foo">ipsum</a> <a href="http://foo.com/"><strong>dolor</strong></a> sit<br>amet .foo { color: #fff; } '
-      ],
-      [
-        'Lo<!-- comment -->rem</b> <a href=pants title="foo>ipsum <a href="http://foo.com/"><strong>dolor</a></strong> sit<br/>amet <script>alert("hello world");',
-        'Lorem <a href="pants" title="foo&gt;ipsum &lt;a href="><strong>dolor</strong></a> sit<br>amet '
-      ],
-      [
-        '<p>a</p><blockquote>b',
-        '<p>a</p><blockquote>b</blockquote>'
-      ],
-      [
-        '<b>Lo<!-- comment -->rem</b> <a href="javascript:pants" title="foo">ipsum</a> <a href="http://foo.com/"><strong>dolor</strong></a> sit<br/>amet <<foo>script>alert("hello world");</script>',
-        '<b>Lorem</b> <a title="foo">ipsum</a> <a href="http://foo.com/"><strong>dolor</strong></a> sit<br>amet &lt;script&gt;alert("hello world");'
-      ]
-    ]
+    'protocol-based JS injection: long UTF-8 encoding without semicolons' => [
+      '<a href=&#0000106&#0000097&#0000118&#0000097&#0000115&#0000099&#0000114&#0000105&#0000112&#0000116&#0000058&#0000097&#0000108&#0000101&#0000114&#0000116&#0000040&#0000039&#0000088&#0000083&#0000083&#0000039&#0000041>foo</a>',
+      '<a>foo</a>'
+    ],
     # rubocop:enable Layout/LineLength
 
-    def test_should_sanitize_html_strings
-      STRINGS.each do |input, expected|
-        assert_equal expected, filter(input)
-      end
-    end
-
-    # samples taken from the Sanitize test suite
-    PROTOCOLS = {
-      'protocol-based JS injection: simple, no spaces' => [
-        '<a href="javascript:alert(\'XSS\');">foo</a>',
-        '<a>foo</a>'
-      ],
-
-      'protocol-based JS injection: simple, spaces before' => [
-        '<a href="javascript    :alert(\'XSS\');">foo</a>',
-        '<a>foo</a>'
-      ],
-
-      'protocol-based JS injection: simple, spaces after' => [
-        '<a href="javascript:    alert(\'XSS\');">foo</a>',
-        '<a>foo</a>'
-      ],
-
-      'protocol-based JS injection: simple, spaces before and after' => [
-        '<a href="javascript    :   alert(\'XSS\');">foo</a>',
-        '<a>foo</a>'
-      ],
-
-      'protocol-based JS injection: preceding colon' => [
-        '<a href=":javascript:alert(\'XSS\');">foo</a>',
-        '<a>foo</a>'
-      ],
-
-      'protocol-based JS injection: UTF-8 encoding' => [
-        '<a href="javascript&#58;">foo</a>',
-        '<a>foo</a>'
-      ],
-
-      'protocol-based JS injection: long UTF-8 encoding' => [
-        '<a href="javascript&#0058;">foo</a>',
-        '<a>foo</a>'
-      ],
-
-      # rubocop:disable Layout/LineLength
-      'protocol-based JS injection: long UTF-8 encoding without semicolons' => [
-        '<a href=&#0000106&#0000097&#0000118&#0000097&#0000115&#0000099&#0000114&#0000105&#0000112&#0000116&#0000058&#0000097&#0000108&#0000101&#0000114&#0000116&#0000040&#0000039&#0000088&#0000083&#0000083&#0000039&#0000041>foo</a>',
-        '<a>foo</a>'
-      ],
-      # rubocop:enable Layout/LineLength
-
-      'protocol-based JS injection: hex encoding' => [
-        '<a href="javascript&#x3A;">foo</a>',
-        '<a>foo</a>'
-      ],
-
-      'protocol-based JS injection: long hex encoding' => [
-        '<a href="javascript&#x003A;">foo</a>',
-        '<a>foo</a>'
-      ],
-
-      'protocol-based JS injection: hex encoding without semicolons' => [
-        '<a href=&#x6A&#x61&#x76&#x61&#x73&#x63&#x72&#x69&#x70&#x74&#x3A&#x61&#x6C&#x65&#x72&#x74&#x28&#x27&#x58&#x53&#x53&#x27&#x29>foo</a>',
-        '<a>foo</a>'
-      ],
-
-      'protocol-based JS injection: null char' => [
-        "<img src=java\0script:alert(\"XSS\")>",
-        '<img src="java">'
-        # '<img>'
-      ],
-
-      'protocol-based JS injection: invalid URL char' => [
-        '<img src=java\script:alert("XSS")>',
-        '<img>'
-      ],
-
-      'protocol-based JS injection: spaces and entities' => [
-        '<img src=" &#14;  javascript:alert(\'XSS\');">',
-        '<img src="">'
-        # '<img>'
-      ],
-
-      'protocol whitespace' => [
-        '<a href=" http://example.com/"></a>',
-        '<a href="http://example.com/"></a>'
-      ],
-
-      'data images sources' => [
-        '<img src="data:image/png;base64,foobar">',
-        '<img>'
-      ],
-
-      'data URIs' => [
-        '<a href="data:text/html;base64,foobar">XSS</a>',
-        '<a>XSS</a>'
-      ],
-
-      'vbscript URIs' => [
-        '<a href="vbscript:foobar">XSS</a>',
-        '<a>XSS</a>'
-      ],
-    }
-
-    PROTOCOLS.each do |name, strings|
-      test "should not allow #{name}" do
-        input, expected = *strings
-        assert_equal expected, filter(input)
-      end
+    'protocol-based JS injection: hex encoding' => [
+      '<a href="javascript&#x3A;">foo</a>',
+      '<a>foo</a>'
+    ],
+
+    'protocol-based JS injection: long hex encoding' => [
+      '<a href="javascript&#x003A;">foo</a>',
+      '<a>foo</a>'
+    ],
+
+    'protocol-based JS injection: hex encoding without semicolons' => [
+      '<a href=&#x6A&#x61&#x76&#x61&#x73&#x63&#x72&#x69&#x70&#x74&#x3A&#x61&#x6C&#x65&#x72&#x74&#x28&#x27&#x58&#x53&#x53&#x27&#x29>foo</a>',
+      '<a>foo</a>'
+    ],
+
+    'protocol-based JS injection: null char' => [
+      "<img src=java\0script:alert(\"XSS\")>",
+      '<img src="java">'
+      # '<img>'
+    ],
+
+    'protocol-based JS injection: invalid URL char' => [
+      '<img src=java\script:alert("XSS")>',
+      '<img>'
+    ],
+
+    'protocol-based JS injection: spaces and entities' => [
+      '<img src=" &#14;  javascript:alert(\'XSS\');">',
+      '<img src="">'
+      # '<img>'
+    ],
+
+    'protocol whitespace' => [
+      '<a href=" http://example.com/"></a>',
+      '<a href="http://example.com/"></a>'
+    ],
+
+    'data images sources' => [
+      '<img src="data:image/png;base64,foobar">',
+      '<img>'
+    ],
+
+    'data URIs' => [
+      '<a href="data:text/html;base64,foobar">XSS</a>',
+      '<a>XSS</a>'
+    ],
+
+    'vbscript URIs' => [
+      '<a href="vbscript:foobar">XSS</a>',
+      '<a>XSS</a>'
+    ],
+  }
+
+  PROTOCOLS.each do |name, strings|
+    test "should not allow #{name}" do
+      input, expected = *strings
+      assert_equal expected, filter(input)
     end
   end
 end
diff --git a/test/unit/lib/redmine/wiki_formatting/common_mark/syntax_highlight_filter_test.rb b/test/unit/lib/redmine/wiki_formatting/common_mark/syntax_highlight_filter_test.rb
index 70cc95301..5d7479dda 100644
--- a/test/unit/lib/redmine/wiki_formatting/common_mark/syntax_highlight_filter_test.rb
+++ b/test/unit/lib/redmine/wiki_formatting/common_mark/syntax_highlight_filter_test.rb
@@ -18,72 +18,70 @@
 # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 
 require_relative '../../../../../test_helper'
-if Object.const_defined?(:Commonmarker)
-  require 'redmine/wiki_formatting/common_mark/syntax_highlight_filter'
+require 'redmine/wiki_formatting/common_mark/syntax_highlight_filter'
 
-  class Redmine::WikiFormatting::CommonMark::SyntaxHighlightFilterTest < ActiveSupport::TestCase
-    def filter(html)
-      Redmine::WikiFormatting::CommonMark::SyntaxHighlightFilter.to_html(html, @options)
-    end
+class Redmine::WikiFormatting::CommonMark::SyntaxHighlightFilterTest < ActiveSupport::TestCase
+  def filter(html)
+    Redmine::WikiFormatting::CommonMark::SyntaxHighlightFilter.to_html(html, @options)
+  end
 
-    def setup
-      @options = { }
-    end
+  def setup
+    @options = { }
+  end
 
-    def test_should_highlight_supported_language
-      input = <<~HTML
-        <pre><code class="language-ruby">
-        def foo
-        end
-        </code></pre>
-      HTML
-      expected = <<~HTML
-        <pre><code class="ruby syntaxhl" data-language="ruby">
-        <span class="k">def</span> <span class="nf">foo</span>
-        <span class="k">end</span>
-        </code></pre>
-      HTML
-      assert_equal expected, filter(input)
-    end
+  def test_should_highlight_supported_language
+    input = <<~HTML
+      <pre><code class="language-ruby">
+      def foo
+      end
+      </code></pre>
+    HTML
+    expected = <<~HTML
+      <pre><code class="ruby syntaxhl" data-language="ruby">
+      <span class="k">def</span> <span class="nf">foo</span>
+      <span class="k">end</span>
+      </code></pre>
+    HTML
+    assert_equal expected, filter(input)
+  end
 
-    def test_should_highlight_supported_language_with_special_chars
-      input = <<~HTML
-        <pre><code class="language-c-k&amp;r">
-        int i;
-        </code></pre>
-      HTML
-      expected = <<~HTML
-        <pre><code data-language="c-k&amp;r">
-        int i;
-        </code></pre>
-      HTML
-      assert_equal expected, filter(input)
-    end
+  def test_should_highlight_supported_language_with_special_chars
+    input = <<~HTML
+      <pre><code class="language-c-k&amp;r">
+      int i;
+      </code></pre>
+    HTML
+    expected = <<~HTML
+      <pre><code data-language="c-k&amp;r">
+      int i;
+      </code></pre>
+    HTML
+    assert_equal expected, filter(input)
+  end
 
-    def test_should_strip_code_class_and_preserve_data_language_attr_for_unknown_language
-      input = <<~HTML
-        <pre><code class="language-foobar">
-        def foo
-        end
-        </code></pre>
-      HTML
-      expected = <<~HTML
-        <pre><code data-language="foobar">
-        def foo
-        end
-        </code></pre>
-      HTML
-      assert_equal expected, filter(input)
-    end
+  def test_should_strip_code_class_and_preserve_data_language_attr_for_unknown_language
+    input = <<~HTML
+      <pre><code class="language-foobar">
+      def foo
+      end
+      </code></pre>
+    HTML
+    expected = <<~HTML
+      <pre><code data-language="foobar">
+      def foo
+      end
+      </code></pre>
+    HTML
+    assert_equal expected, filter(input)
+  end
 
-    def test_should_ignore_code_without_class
-      input = <<~HTML
-        <pre><code>
-        def foo
-        end
-        </code></pre>
-      HTML
-      assert_equal input, filter(input)
-    end
+  def test_should_ignore_code_without_class
+    input = <<~HTML
+      <pre><code>
+      def foo
+      end
+      </code></pre>
+    HTML
+    assert_equal input, filter(input)
   end
 end