diff --git a/spec/legacy/unit/lib/redmine/wiki_formatting/textile_formatter_spec.rb b/spec/legacy/unit/lib/redmine/wiki_formatting/textile_formatter_spec.rb
index fc60e3f17b..4c0ab42976 100644
--- a/spec/legacy/unit/lib/redmine/wiki_formatting/textile_formatter_spec.rb
+++ b/spec/legacy/unit/lib/redmine/wiki_formatting/textile_formatter_spec.rb
@@ -30,6 +30,8 @@
 require 'legacy_spec_helper'
 
 describe Redmine::WikiFormatting::Textile::Formatter do
+  include Rails::Dom::Testing::Assertions
+
   before do
     @formatter = Redmine::WikiFormatting::Textile::Formatter
   end
@@ -232,7 +234,7 @@ EXPECTED
 
   def assert_html_output(to_test, expect_paragraph = true)
     to_test.each do |text, expected|
-      assert_equal((expect_paragraph ? "<p>#{expected}</p>" : expected), @formatter.new(text).to_html, "Formatting the following text failed:\n===\n#{text}\n===\n")
+      assert_dom_equal((expect_paragraph ? "<p>#{expected}</p>" : expected), @formatter.new(text).to_html, "Formatting the following text failed:\n===\n#{text}\n===\n")
     end
   end