DRY in builders

lib/capybara/selector/builders/css_builder.rb

@@ -35,8 +35,7 @@ module Capybara
           when XPath::Expression
             raise ArgumentError, 'XPath expressions are not supported for the :class filter with CSS based selectors'
           when Regexp
-            strs = Selector::RegexpDisassembler.new(classes).substrings
-            strs.map { |str| "[class*='#{str}'#{' i' if classes.casefold?}]" }.join
+            attribute_conditions(class: classes)
           else
             cls = Array(classes).group_by { |cl| cl.start_with? '!' }
             (cls[false].to_a.map { |cl| ".#{Capybara::Selector::CSS.escape(cl)}" } +

lib/capybara/selector/builders/xpath_builder.rb

@@ -26,10 +26,8 @@ module Capybara
 
         def class_conditions(classes)
           case classes
-          when XPath::Expression
-            XPath.attr(:class)[classes]
-          when Regexp
-            XPath.attr(:class)[regexp_to_xpath_conditions(classes)]
+          when XPath::Expression, Regexp
+            attribute_conditions(class: classes)
           else
             Array(classes).map do |klass|
               if klass.start_with?('!')