diff --git a/lib/table_of_contents/configuration.rb b/lib/table_of_contents/configuration.rb
index 595c73d..cb6e6d9 100644
--- a/lib/table_of_contents/configuration.rb
+++ b/lib/table_of_contents/configuration.rb
@@ -22,10 +22,10 @@ class Configuration
       def initialize(options)
         options = generate_option_hash(options)
 
-        @toc_levels = options['min_level']..options['max_level']
+        @toc_levels = (options['min_level']..options['max_level']).to_a
         @ordered_list = options['ordered_list']
         @no_toc_class = 'no_toc'
-        @no_toc_section_class = options['no_toc_section_class']
+        @no_toc_section_class = Array(options['no_toc_section_class'])
         @list_id = options['list_id']
         @list_class = options['list_class']
         @sublist_class = options['sublist_class']
diff --git a/lib/table_of_contents/parser.rb b/lib/table_of_contents/parser.rb
index 23509cc..fb5d793 100644
--- a/lib/table_of_contents/parser.rb
+++ b/lib/table_of_contents/parser.rb
@@ -24,12 +24,8 @@ def build_toc
 
       def inject_anchors_into_html
         @entries.each do |entry|
-          # NOTE: `entry[:id]` is automatically URL encoded by Nokogiri
-          entry[:header_content].add_previous_sibling(
-            %(<a class="anchor" href="##{entry[:id]}" aria-hidden="true"><span class="octicon octicon-link"></span></a>)
-          )
+          entry[:header_content].wrap(%(<a class="anchor" href="##{entry[:id]}" aria-hidden="true"><span class="octicon octicon-link"></span></a>))
         end
-
         @doc.inner_html
       end
 
diff --git a/test/parser/test_inject_anchors_filter.rb b/test/parser/test_inject_anchors_filter.rb
index 61d00b9..03bcd1b 100644
--- a/test/parser/test_inject_anchors_filter.rb
+++ b/test/parser/test_inject_anchors_filter.rb
@@ -12,8 +12,9 @@ def setup
   def test_injects_anchors_into_content
     html = @parser.inject_anchors_into_html
 
-    assert_match(%r{<a class="anchor" href="#simple-h1" aria-hidden="true"><span.*span></a>Simple H1}, html)
+    assert_match(%r{<a class="anchor" href="#simple-h1" aria-hidden="true"><span.*span>Simple H1</a>}, html)
   end
+  
 
   def test_does_not_inject_toc
     html = @parser.inject_anchors_into_html
diff --git a/test/parser/test_toc_filter.rb b/test/parser/test_toc_filter.rb
index 6fe2fb7..ebd8103 100644
--- a/test/parser/test_toc_filter.rb
+++ b/test/parser/test_toc_filter.rb
@@ -12,7 +12,7 @@ def setup
   def test_injects_anchors
     html = @parser.toc
 
-    assert_match(%r{<a class="anchor" href="#simple-h1" aria-hidden="true"><span.*span></a>Simple H1}, html)
+    assert_match(%r{<a class="anchor" href="#simple-h1" aria-hidden="true"><span.*span>Simple H1</a>}, html)
   end
 
   def test_nested_toc
diff --git a/test/parser/test_various_toc_html.rb b/test/parser/test_various_toc_html.rb
index 9fdd221..6cb6e4d 100644
--- a/test/parser/test_various_toc_html.rb
+++ b/test/parser/test_various_toc_html.rb
@@ -172,9 +172,9 @@ def test_japanese_toc
     assert_equal(expected, parser.build_toc)
     html_with_anchors = parser.inject_anchors_into_html
 
-    assert_match(%r{<a class="anchor" href="#%E3%81%82" aria-hidden="true"><span.*span></a>あ}, html_with_anchors)
-    assert_match(%r{<a class="anchor" href="#%E3%81%84" aria-hidden="true"><span.*span></a>い}, html_with_anchors)
-    assert_match(%r{<a class="anchor" href="#%E3%81%86" aria-hidden="true"><span.*span></a>う}, html_with_anchors)
+    assert_match(%r{<a class="anchor" href="#%E3%81%82" aria-hidden="true"><span.*span>あ</a>}, html_with_anchors)
+    assert_match(%r{<a class="anchor" href="#%E3%81%84" aria-hidden="true"><span.*span>い</a>}, html_with_anchors)
+    assert_match(%r{<a class="anchor" href="#%E3%81%86" aria-hidden="true"><span.*span>う</a>}, html_with_anchors)
   end
 
   # ref. https://github.com/toshimaru/jekyll-toc/issues/45
diff --git a/test/test_configuration.rb b/test/test_configuration.rb
index a3e77c9..f0d16dd 100644
--- a/test/test_configuration.rb
+++ b/test/test_configuration.rb
@@ -6,9 +6,9 @@ class TestConfiguration < Minitest::Test
   def test_default_configuration
     configuration = Jekyll::TableOfContents::Configuration.new({})
 
-    assert_equal(1..6, configuration.toc_levels)
+    assert_equal((1..6).to_a, configuration.toc_levels)
     refute(configuration.ordered_list)
-    assert_equal('no_toc_section', configuration.no_toc_section_class)
+    assert_equal(['no_toc_section'], configuration.no_toc_section_class)
     assert_equal('toc', configuration.list_id)
     assert_equal('section-nav', configuration.list_class)
     assert_equal('', configuration.sublist_class)
@@ -19,9 +19,9 @@ def test_default_configuration
   def test_type_error
     configuration = Jekyll::TableOfContents::Configuration.new('TypeError!')
 
-    assert_equal(1..6, configuration.toc_levels)
+    assert_equal((1..6).to_a, configuration.toc_levels)
     refute(configuration.ordered_list)
-    assert_equal('no_toc_section', configuration.no_toc_section_class)
+    assert_equal(['no_toc_section'], configuration.no_toc_section_class)
     assert_equal('toc', configuration.list_id)
     assert_equal('section-nav', configuration.list_class)
     assert_equal('', configuration.sublist_class)