resolves #1040 add syntax highlighter adapter for Rouge (PR #3033)

- add SyntaxHighlighter adapter implementation for Rouge
- support CGI options attached to language (e.g., "console?prompt=$ ")
- change CSS class of line numbering table for Pygments and Rouge to linenotable
- reuse styles from default stylesheet to layout the line number column
- remove nested pre wrapper in Pygments output when line numbering is enabled and linenums mode is inline
- ensure syntax highlighter library is loaded when looking up base style
- add the rouge gem as a development dependency

8 files changed, 445 insertions, 22 deletions

diff --git a/CHANGELOG.adoc b/CHANGELOG.adoc
index c84d25a8..41749f17 100644
--- a/CHANGELOG.adoc
+++ b/CHANGELOG.adoc
@@ -20,6 +20,7 @@ Enhancements::
   * drop support for Ruby < 2.3 and JRuby < 9.1 and remove workarounds (#2764)
   * drop support for Slim < 3 (#2998)
   * make syntax highlighter pluggable; extract all logic into adapter classes (#2106)
+  * add syntax highlighter adapter for Rouge (#1040)
   * add support for start attribute when using prettify to highlight source blocks with line numbering enabled
   * use String#encode to encode String as UTF-8 instead of using String#force_encoding (#2764)
   * add FILE_READ_MODE, URI_READ_MODE, and FILE_WRITE_MODE constants to control open mode when reading files and URIs and writing files (#2764)
@@ -41,6 +42,7 @@ Improvements::
   * value comparison in AbstractNode#attr? is only performed if expected value is truthy
   * align default CodeRay style with style for other syntax highlighters (#2106)
   * ensure linenos class is added to linenos column when source highlighter is pygments and pygments-css=style
+  * rename CSS class of Pygments line numbering table to linenotable (to align with Rouge) (#1040)
 
 Bug Fixes::
 
diff --git a/asciidoctor.gemspec b/asciidoctor.gemspec
index 51c4e6c7..bfa11491 100644
--- a/asciidoctor.gemspec
+++ b/asciidoctor.gemspec
@@ -51,6 +51,8 @@ Gem::Specification.new do |s|
   s.add_development_dependency 'minitest', '~> 5.11.0'
   s.add_development_dependency 'nokogiri', '~> 1.10.0'
   s.add_development_dependency 'rake', '~> 12.3.0'
+  # Asciidoctor supports Rouge >= 3
+  s.add_development_dependency 'rouge', '~> 3.3.0'
   s.add_development_dependency 'rspec-expectations', '~> 3.8.0'
   s.add_development_dependency 'slim', '~> 4.0.0'
   s.add_development_dependency 'tilt', '~> 2.0.0'
diff --git a/data/stylesheets/asciidoctor-default.css b/data/stylesheets/asciidoctor-default.css
index d0b21e57..a9f91bf1 100644
--- a/data/stylesheets/asciidoctor-default.css
+++ b/data/stylesheets/asciidoctor-default.css
@@ -223,13 +223,12 @@ pre.prettyprint .linenums{line-height:1.45;margin-left:2em}
 pre.prettyprint li{background:none;list-style-type:inherit;padding-left:0}
 pre.prettyprint li code[data-lang]::before{opacity:1}
 pre.prettyprint li:not(:first-child) code[data-lang]::before{display:none}
-table.pygments-table{border-collapse:separate;border:0;margin-bottom:0;background:none}
-table.pygments-table td{color:inherit;vertical-align:top;padding:0;line-height:inherit;white-space:normal}
-table.pygments-table td.code{padding-left:.75em}
-pre.pygments .lineno,table.pygments-table td.linenos{border-right:1px solid currentColor;opacity:.35}
-pre.pygments .lineno{display:inline-block;margin-right:.75em}
+table.linenotable{border-collapse:separate;border:0;margin-bottom:0;background:none}
+table.linenotable td[class]{color:inherit;vertical-align:top;padding:0;line-height:inherit;white-space:normal}
+table.linenotable td.code{padding-left:.75em}
+table.linenotable td.linenos{border-right:1px solid currentColor;opacity:.35;padding-right:.5em}
+pre.pygments .lineno{border-right:1px solid currentColor;opacity:.35;display:inline-block;margin-right:.75em}
 pre.pygments .lineno::before{content:"";margin-right:-.125em}
-table.pygments-table td.linenos{padding-right:.5em}
 .quoteblock{margin:0 1em 1.25em 1.5em;display:table}
 .quoteblock>.title{margin-left:-1.5em;margin-bottom:.75em}
 .quoteblock blockquote,.quoteblock p{color:rgba(0,0,0,.85);font-size:1.15rem;line-height:1.75;word-spacing:.1em;letter-spacing:0;font-style:italic;text-align:justify}
diff --git a/lib/asciidoctor/rouge_ext.rb b/lib/asciidoctor/rouge_ext.rb
new file mode 100644
index 00000000..a4ed621a
--- /dev/null
+++ b/lib/asciidoctor/rouge_ext.rb
@@ -0,0 +1,38 @@
+require 'rouge'
+
+module Asciidoctor; module RougeExt; module Formatters
+  class HTMLTable < ::Rouge::Formatter
+    def initialize delegate, opts
+      @delegate = delegate
+      @start_line = opts[:start_line] || 1
+    end
+
+    def stream tokens
+      formatted_code = @delegate.format tokens
+      formatted_code += LF unless formatted_code.end_with? LF, HangingEndSpanTagCs
+      last_lineno = (first_lineno = @start_line) + (formatted_code.count LF) - 1 # assume number of newlines is constant
+      lineno_format = %(%#{(::Math.log10 last_lineno).floor + 1}i)
+      formatted_linenos = ((first_lineno..last_lineno).map {|lineno| sprintf lineno_format, lineno } << '').join LF
+      yield %(<table class="linenotable"><tbody><tr><td class="linenos gl"><pre class="lineno">#{formatted_linenos}</pre></td><td class="code"><pre>#{formatted_code}</pre></td></tr></tbody></table>)
+    end
+  end
+
+  class HTMLLineHighlighter < ::Rouge::Formatter
+    def initialize delegate, opts
+      @delegate = delegate
+      @lines = opts[:lines] || []
+    end
+
+    def stream tokens
+      lineno = 0
+      token_lines tokens do |tokens_in_line|
+        yield (@lines.include? lineno += 1) ? %(<span class="hll">#{@delegate.format tokens_in_line}#{LF}</span>) : %(#{@delegate.format tokens_in_line}#{LF})
+      end
+    end
+  end
+
+  HangingEndSpanTagCs = %(\n</span>)
+  LF = ?\n
+
+  private_constant :HangingEndSpanTagCs, :LF
+end; end; end
diff --git a/lib/asciidoctor/syntax_highlighter.rb b/lib/asciidoctor/syntax_highlighter.rb
index 81e2d206..dd1c287a 100644
--- a/lib/asciidoctor/syntax_highlighter.rb
+++ b/lib/asciidoctor/syntax_highlighter.rb
@@ -8,7 +8,7 @@ module Asciidoctor
 # that returns true. The companion docinfo method will then be called to insert markup into the output document. The
 # docinfo functionality is available to both adapter types.
 #
-# Asciidoctor provides several built-in adapters, including coderay, pygments, highlight.js, html-pipeline, and
+# Asciidoctor provides several built-in adapters, including coderay, pygments, rouge, highlight.js, html-pipeline, and
 # prettify. Additional adapters can be registered using SyntaxHighlighter.register or by supplying a custom factory.
 module SyntaxHighlighter
   # Public: Returns the String name of this syntax highlighter for referencing it in messages and option names.
@@ -175,9 +175,8 @@ module SyntaxHighlighter
             @@mutex.synchronize { register syntax_highlighter, *names }
       end
 
-      # In addition to retrieving the syntax highlighter class or object registered for the specified name, this
-      # method will lazy require and register additional built-in implementations (coderay, pygments, and prettify).
-      # Refer to {Factory#for} for parameters and return value.
+      # This method will lazy require and register additional built-in implementations, which include coderay,
+      # pygments, rouge, and prettify. Refer to {Factory#for} for parameters and return value.
       def for name
         @@registry.fetch name do
           @@mutex.synchronize do
@@ -198,6 +197,7 @@ module SyntaxHighlighter
         'coderay' => %(#{__dir__}/syntax_highlighter/coderay),
         'prettify' => %(#{__dir__}/syntax_highlighter/prettify),
         'pygments' => %(#{__dir__}/syntax_highlighter/pygments),
+        'rouge' => %(#{__dir__}/syntax_highlighter/rouge),
       }
 
       private
diff --git a/lib/asciidoctor/syntax_highlighter/pygments.rb b/lib/asciidoctor/syntax_highlighter/pygments.rb
index d9feca7c..b1adaca3 100644
--- a/lib/asciidoctor/syntax_highlighter/pygments.rb
+++ b/lib/asciidoctor/syntax_highlighter/pygments.rb
@@ -36,12 +36,8 @@ class SyntaxHighlighter::PygmentsAdapter < SyntaxHighlighter::Base
         node.sub_specialchars source # handles nil response from ::Pygments::Lexer#highlight
       end
     elsif (highlighted = lexer.highlight source, options: highlight_opts)
-      if linenos
-        highlighted = highlighted.gsub StyledLinenoSpanTagRx, LinenoSpanTagCs if noclasses
-        highlighted.sub WrapperTagRx, PreTagCs
-      else
-        highlighted.sub WrapperTagRx, '\1'
-      end
+      highlighted = highlighted.gsub StyledLinenoSpanTagRx, LinenoSpanTagCs if linenos && noclasses
+      highlighted.sub WrapperTagRx, '\1'
     else
       node.sub_specialchars source # handles nil response from ::Pygments::Lexer#highlight
     end
@@ -103,7 +99,7 @@ class SyntaxHighlighter::PygmentsAdapter < SyntaxHighlighter::Base
     private
 
     def base_style style
-      @@base_style_cache[style || DEFAULT_STYLE]
+      library_available? ? @@base_style_cache[style || DEFAULT_STYLE] : nil
     end
 
     def style_available? style
@@ -141,8 +137,10 @@ class SyntaxHighlighter::PygmentsAdapter < SyntaxHighlighter::Base
   PreTagCs = '<pre>\1</pre>'
   StyledLinenoColumnStartTagsRx = /<td><div class="linenodiv" style="[^"]+?"><pre style="[^"]+?">/
   StyledLinenoSpanTagRx = %r(<span style="background-color: #f0f0f0; padding: 0 5px 0 5px">( *\d+ )</span>)
-  WRAPPER_CLASS = 'pygments-'
-  # NOTE <pre> has style attribute when pygments-css=style; <div> has trailing newline when pygments-linenums-mode=table; initial <span></span> preserves leading blank lines
+  WRAPPER_CLASS = 'lineno' # doesn't appear in output
+  # NOTE <pre> has style attribute when pygments-css=style
+  # NOTE <div> has trailing newline when pygments-linenums-mode=table
+  # NOTE initial <span></span> preserves leading blank lines
   WrapperTagRx = %r(<div class="#{WRAPPER_CLASS}"><pre\b[^>]*?>(.*)</pre></div>\n*)m
 
   private_constant :CodeCellStartTagCs, :LinenoColumnStartTagsCs, :LinenoSpanTagCs, :PreTagCs, :StyledLinenoColumnStartTagsRx, :StyledLinenoSpanTagRx, :WrapperTagRx, :WRAPPER_CLASS
diff --git a/lib/asciidoctor/syntax_highlighter/rouge.rb b/lib/asciidoctor/syntax_highlighter/rouge.rb
new file mode 100644
index 00000000..c78bc357
--- /dev/null
+++ b/lib/asciidoctor/syntax_highlighter/rouge.rb
@@ -0,0 +1,126 @@
+module Asciidoctor
+class SyntaxHighlighter::RougeAdapter < SyntaxHighlighter::Base
+  register_for 'rouge'
+
+  def initialize *args
+    super
+    @requires_stylesheet = nil
+    @style = nil
+  end
+
+  def highlight?
+    library_available?
+  end
+
+  def highlight node, source, lang, opts
+    lexer = (::Rouge::Lexer.find_fancy lang) || ::Rouge::Lexers::PlainText
+    lexer_opts = lexer.tag == 'php' && !(node.option? 'mixed') ? { start_inline: true } : {}
+    @style ||= (style = opts[:style]) && (style_available? style) || DEFAULT_STYLE
+    if opts[:css_mode] == :class
+      @requires_stylesheet = true
+      formatter = ::Rouge::Formatters::HTML.new @style
+    else
+      formatter = ::Rouge::Formatters::HTMLInline.new @style
+    end
+    if (highlight_lines = opts[:highlight_lines])
+      formatter = RougeExt::Formatters::HTMLLineHighlighter.new formatter, lines: highlight_lines
+    end
+    if opts[:line_numbers]
+      formatter = RougeExt::Formatters::HTMLTable.new formatter, start_line: opts[:start_line_number]
+      if opts[:callouts]
+        highlighted = formatter.format lexer.lex source, lexer_opts
+        return [highlighted, (idx = highlighted.index CodeCellStartTagCs) ? idx + CodeCellStartTagCs.length : nil]
+      end
+    end
+    formatter.format lexer.lex source, lexer_opts
+  end
+
+  def format node, lang, opts
+    lang = (lang.split '?', 2)[0] if lang.include? '?'
+    if opts[:css_mode] != :class && (@style = (style = opts[:style]) && (style_available? style) || DEFAULT_STYLE) &&
+        (pre_style_attr_val = base_style @style)
+      opts[:transform] = -> pre, _ { pre['style'] = pre_style_attr_val }
+    end
+    super
+  end
+
+  def docinfo? location
+    @requires_stylesheet && location == :footer
+  end
+
+  def docinfo location, doc, opts
+    if opts[:linkcss]
+      %(<link rel="stylesheet" href="#{doc.normalize_web_path (stylesheet_basename @style), (doc.attr 'stylesdir', ''), false}"#{opts[:self_closing_tag_slash]}>)
+    else
+      %(<style>
+#{read_stylesheet @style}
+</style>)
+    end
+  end
+
+  def write_stylesheet? doc
+    @requires_stylesheet
+  end
+
+  def write_stylesheet doc, to_dir
+    ::File.write (::File.join to_dir, (stylesheet_basename @style)), (read_stylesheet @style), mode: FILE_WRITE_MODE
+  end
+
+  module Loader
+    private
+
+    def library_available?
+      (@@library_status ||= load_library) == :loaded ? true : nil
+    end
+
+    def load_library
+      (defined? ::Rouge::Lexer) ? :loaded : (Helpers.require_library %(#{::File.dirname __dir__}/rouge_ext), 'rouge', :warn).nil? ? :unavailable : :loaded
+    end
+  end
+
+  module Styles
+    include Loader
+
+    def read_stylesheet style
+      library_available? ? @@stylesheet_cache[style || DEFAULT_STYLE] : '/* Rouge CSS disabled because Rouge is not available. */'
+    end
+
+    def stylesheet_basename style
+      %(rouge-#{style || DEFAULT_STYLE}.css)
+    end
+
+    private
+
+    def base_style style
+      library_available? ? @@base_style_cache[style || DEFAULT_STYLE] : nil
+    end
+
+    def style_available? style
+      (::Rouge::Theme.find style) && style
+    end
+
+    (@@base_style_cache = {}).default_proc = proc do |cache, key|
+      base_style = (theme = ::Rouge::Theme.find key).base_style
+      (val = base_style[:fg]) && ((style ||= []) << %(color: #{theme.palette val}))
+      (val = base_style[:bg]) && ((style ||= []) << %(background-color: #{theme.palette val}))
+      @@base_style_cache = cache.merge key => (resolved_base_style = style && (style.join ';'))
+      resolved_base_style
+    end
+    (@@stylesheet_cache = {}).default_proc = proc do |cache, key|
+      @@stylesheet_cache = cache.merge key => (stylesheet = ((::Rouge::Theme.find key).render scope: BASE_SELECTOR))
+      stylesheet
+    end
+
+    DEFAULT_STYLE = 'github'
+    BASE_SELECTOR = 'pre.rouge'
+
+    private_constant :BASE_SELECTOR
+  end
+
+  include Loader, Styles # adds methods to instance
+
+  CodeCellStartTagCs = '<td class="code">'
+
+  private_constant :CodeCellStartTagCs
+end
+end
diff --git a/test/syntax_highlighter_test.rb b/test/syntax_highlighter_test.rb
index 9d972c43..8e2c85fb 100644
--- a/test/syntax_highlighter_test.rb
+++ b/test/syntax_highlighter_test.rb
@@ -586,8 +586,223 @@ context 'Syntax Highlighter' do
     end
   end
 
+  context 'Rouge' do
+    test 'should syntax highlight source if source-highlighter attribute is set' do
+      input = <<~'EOS'
+      :source-highlighter: rouge
+
+      [source,ruby]
+      ----
+      require 'rouge'
+
+      html = Rouge::Formatters::HTML.new.format(Rouge::Lexers::Ruby.new.lex('puts "Hello, world!"'))
+      ----
+      EOS
+      output = convert_string input, safe: :safe, linkcss_default: true
+      assert_xpath '//pre[@class="rouge highlight"]/code[@data-lang="ruby"]/span[@class="no"][text()="Rouge"]', output, 2
+      assert_includes output, 'pre.rouge .no {'
+    end
+
+    test 'should default to plain text lexer if lexer cannot be resolved for language' do
+      input = <<~'EOS'
+      :source-highlighter: rouge
+
+      [source,lolcode]
+      ----
+      CAN HAS STDIO?
+      PLZ OPEN FILE "LOLCATS.TXT"?
+      KTHXBYE
+      ----
+      EOS
+      output = convert_string_to_embedded input, safe: :safe
+      assert_css 'code[data-lang=lolcode]', output, 1
+      assert_css 'code span', output, 0
+      assert_xpath %(//code[text()='CAN HAS STDIO?\nPLZ OPEN FILE "LOLCATS.TXT"?\nKTHXBYE']), output, 1
+    end
+
+    test 'should honor cgi-style options on language' do
+      input = <<~'EOS'
+      :source-highlighter: rouge
+
+      [source,"console?prompt=$> "]
+      ----
+      $> asciidoctor --version
+      ----
+      EOS
+      output = convert_string_to_embedded input, safe: :safe
+      assert_css 'code[data-lang=console]', output, 1
+      assert_css 'code span.gp', output, 1
+    end
+
+    test 'should set starting line number in HTML output if linenums option is enabled and start attribute is set' do
+      input = <<~'EOS'
+      [source%linenums,ruby,start=9]
+      ----
+      puts 'Hello, World!'
+      puts 'Goodbye, World!'
+      ----
+      EOS
+      output = convert_string_to_embedded input, attributes: { 'source-highlighter' => 'rouge' }
+      assert_css 'table.linenotable', output, 1
+      assert_css 'table.linenotable td.linenos', output, 1
+      assert_css 'table.linenotable td.linenos pre.lineno', output, 1
+      assert_css 'table.linenotable td.code', output, 1
+      assert_css 'table.linenotable td.code pre:not([class])', output, 1
+      assert_xpath %(//pre[@class="lineno"][text()=" 9\n10\n"]), output, 1
+    end
+
+    test 'should restore callout marks to correct lines' do
+      ['', '%linenums'].each do |opts|
+        input = <<~EOS
+        :source-highlighter: rouge
+
+        [source#{opts},ruby]
+        ----
+        require 'rouge' # <1>
+
+        html = Rouge::Formatters::HTML.new.format(Rouge::Lexers::Ruby.new.lex('puts "Hello, world!"')) # <2>
+        puts html # <3> <4>
+        exit 0 # <5><6>
+        ----
+        <1> Load library
+        <2> Highlight source
+        <3> Print to stdout
+        <4> Redirect to a file to capture output
+        <5> Exit program
+        <6> Reports success
+        EOS
+        output = convert_string_to_embedded input, safe: :safe
+        assert_match(/<span class="s1">'rouge'<\/span>.* # <b class="conum">\(1\)<\/b>$/, output)
+        assert_match(/<span class="s1">'puts "Hello, world!"'<\/span>.* # <b class="conum">\(2\)<\/b>$/, output)
+        assert_match(/<span class="n">html<\/span>.* # <b class="conum">\(3\)<\/b> <b class="conum">\(4\)<\/b>$/, output)
+        # NOTE notice there's a newline before the closing </pre> tag when linenums are enabled
+        assert_match(/<span class="mi">0<\/span>.* # <b class="conum">\(5\)<\/b> <b class="conum">\(6\)<\/b>#{opts == '%linenums' ? ?\n : '</code>'}<\/pre>/, output)
+      end
+    end
+
+    test 'should line highlight specified lines when last line is not highlighted' do
+      ['', '%linenums'].each do |opts|
+        input = <<~EOS
+        :source-highlighter: rouge
+
+        [source#{opts},ruby,highlight=1]
+        ----
+        puts 'Hello, world!'
+        puts 'Goodbye, world!'
+        ----
+        EOS
+        # NOTE notice the newline in inside the closing </span> of the highlight span
+        expected = <<~EOS.chomp
+        <span class="hll"><span class="nb">puts</span> <span class="s1">'Hello, world!'</span>
+        </span><span class="nb">puts</span> <span class="s1">'Goodbye, world!'</span>#{opts == '%linenums' ? ?\n : '</code>'}</pre>
+        EOS
+
+        output = convert_string_to_embedded input, safe: :safe
+        assert_includes output, expected
+      end
+    end
+
+    test 'should line highlight specified lines when last line is highlighted' do
+      ['', '%linenums'].each do |opts|
+        input = <<~EOS
+        :source-highlighter: rouge
+
+        [source#{opts},ruby,highlight=2]
+        ----
+        puts 'Hello, world!'
+        puts 'Goodbye, world!'
+        ----
+        EOS
+        # NOTE notice the newline in inside the closing </span> of the highlight span
+        expected = <<~EOS.chomp
+        <span class="nb">puts</span> <span class="s1">'Hello, world!'</span>
+        <span class="hll"><span class="nb">puts</span> <span class="s1">'Goodbye, world!'</span>
+        </span>#{opts == '%linenums' ? '' : '</code>'}</pre>
+        EOS
+
+        output = convert_string_to_embedded input, safe: :safe
+        assert_includes output, expected
+      end
+    end
+
+    test 'should restore callout marks to correct lines if line numbering and line highlighting are enabled' do
+      [1, 2].each do |highlight|
+        input = <<~EOS
+        :source-highlighter: rouge
+
+        [source%linenums,ruby,highlight=#{highlight}]
+        ----
+        require 'rouge' # <1>
+        exit 0 # <2>
+        ----
+        <1> Load library
+        <2> Exit program
+        EOS
+        output = convert_string_to_embedded input, safe: :safe
+        assert_match(/<span class="s1">'rouge'<\/span>.* # <b class="conum">\(1\)<\/b>$/, output)
+        # NOTE notice there's a newline before the closing </pre> tag
+        assert_match(/<span class="mi">0<\/span>.* # <b class="conum">\(2\)<\/b>\n#{highlight == 2 ? '</span>' : ''}<\/pre>/, output)
+      end
+    end
+
+    test 'should gracefully fallback to default style if specified style not recognized' do
+      input = <<~'EOS'
+      :source-highlighter: rouge
+      :rouge-style: unknown
+
+      [source,ruby]
+      ----
+      puts 'Hello, world!'
+      ----
+      EOS
+      output = convert_string input, safe: :safe, linkcss_default: true
+      assert_css 'pre.rouge', output, 1
+      assert_includes output, 'pre.rouge .no {'
+      assert_match %r/pre\.rouge \{\s*background-color: #f8f8f8;/m, output
+    end
+
+    test 'should restore isolated callout mark on last line of source' do
+      input = <<~'EOS'
+      :source-highlighter: rouge
+
+      [source%linenums,ruby]
+      ----
+      require 'app'
+
+      launch_app
+      # <1>
+      ----
+      <1> Profit.
+      EOS
+
+      output = convert_string_to_embedded input, safe: :safe
+      # NOTE notice there's a newline before the closing </pre> tag, but not before the closing </td> tag
+      assert_match(/\n# <b class="conum">\(1\)<\/b>\n<\/pre><\/td>/, output)
+    end
+
+    test 'should number all lines when isolated callout mark is on last line of source and starting line number is set' do
+      input = <<~'EOS'
+      :source-highlighter: rouge
+
+      [source%linenums,ruby,start=5]
+      ----
+      require 'app'
+
+      launch_app
+      # <1>
+      ----
+      <1> Profit.
+      EOS
+
+      output = convert_string_to_embedded input, safe: :safe
+      assert_xpath %(//pre[@class="lineno"][text()="5\n6\n7\n8\n"]), output, 1
+      # NOTE notice there's a newline before the closing </pre> tag, but not before the closing </td> tag
+      assert_match(/\n# <b class="conum">\(1\)<\/b>\n<\/pre><\/td>/, output)
+    end
+  end
+
   context 'Pygments' do
-    test 'should highlight source if source-highlighter attribute is pygments' do
+    test 'should syntax highlight source if source-highlighter attribute is set' do
       input = <<~'EOS'
       :source-highlighter: pygments
       :pygments-style: monokai
@@ -628,7 +843,27 @@ context 'Syntax Highlighter' do
       assert_includes output, '.tok-c { color: #408080;'
     end
 
-    test 'should restore callout marks to correct lines if source highlighter is pygments and table line numbering is enabled' do
+    test 'should number lines if linenums option is set on source block' do
+      input = <<~'EOS'
+      :source-highlighter: pygments
+
+      [source%linenums,ruby]
+      ----
+      puts 'Hello, World!'
+      puts 'Goodbye, World!'
+      ----
+      EOS
+      output = convert_string_to_embedded input, safe: Asciidoctor::SafeMode::SAFE
+      assert_css 'table.linenotable', output, 1
+      assert_css 'table.linenotable td.linenos', output, 1
+      assert_css 'table.linenotable td.linenos .linenodiv', output, 1
+      assert_css 'table.linenotable td.linenos .linenodiv pre:not([class])', output, 1
+      assert_css 'table.linenotable td.code', output, 1
+      assert_css 'table.linenotable td.code pre:not([class])', output, 1
+      assert_xpath %(//*[@class="linenodiv"]/pre[text()="1\n2"]), output, 1
+    end
+
+    test 'should restore callout marks to correct lines if table line numbering is enabled' do
       input = <<~'EOS'
       :source-highlighter: pygments
       :pygments-linenums-mode: table
@@ -652,7 +887,7 @@ context 'Syntax Highlighter' do
       assert_match(/\(\)\)\).*<\/span> # <b class="conum">\(2\)<\/b> <b class="conum">\(3\)<\/b>$/, output)
     end
 
-    test 'should restore isolated callout mark on last line of source when source highlighter is pygments' do
+    test 'should restore isolated callout mark on last line of source' do
       input = <<~'EOS'
       :source-highlighter: pygments
 
@@ -711,8 +946,31 @@ context 'Syntax Highlighter' do
       EOS
 
       output = convert_string_to_embedded input, safe: :safe
+      assert_css 'table.linenotable', output, 0
+      assert_css 'pre', output, 1
       assert_includes output, '<span class="lineno"> 1 </span>'
       assert_includes output, '<span class="lineno">10 </span>'
     end
+
+    test 'should line highlight specified lines' do
+      input = <<~'EOS'
+      :source-highlighter: pygments
+
+      [source,ruby,highlight=1..2]
+      ----
+      puts 'Hello, world!'
+      puts 'Goodbye, world!'
+      ----
+      EOS
+      # NOTE notice the newline is inside the closing </span> of the highlight span
+      expected = <<~'EOS'.chomp
+      <pre class="pygments highlight"><code data-lang="ruby"><span></span><span class="hll"><span class="tok-nb">puts</span> <span class="tok-s1">&#39;Hello, world!&#39;</span>
+      </span><span class="hll"><span class="tok-nb">puts</span> <span class="tok-s1">&#39;Goodbye, world!&#39;</span>
+      </span></code></pre>
+      EOS
+
+      output = convert_string_to_embedded input, safe: :safe
+      assert_includes output, expected
+    end
   end if ENV['PYGMENTS']
 end