fieldset elements should correctly respond to `disabled?`

lib/capybara/selenium/node.rb

@@ -140,7 +140,10 @@ class Capybara::Selenium::Node < Capybara::Driver::Node
   alias :checked? :selected?
 
   def disabled?
-    !native.enabled?
+    return true unless native.enabled?
+    # WebDriver only defines `disabled?` for form controls but fieldset makes sense too
+    return boolean_attr(self[:disabled]) if tag_name == 'fieldset'
+    false
   end
 
   def content_editable?

lib/capybara/spec/session/node_spec.rb

@@ -177,6 +177,11 @@ Capybara::SpecHelper.spec "node" do
       expect(@session.find('//option', text: "A.2")).not_to be_disabled
     end
 
+    it "should see a disabled fieldset as disabled" do
+      @session.visit('/form')
+      expect(@session.find(:css, '#form_disabled_fieldset')).to be_disabled
+    end
+
     context "in a disabled fieldset" do
       # https://html.spec.whatwg.org/#the-fieldset-element
       it "should see elements not in first legend as disabled" do

lib/capybara/spec/views/form.erb

@@ -386,7 +386,7 @@ New line after and before textarea tag
 
 
   <p>
-    <fieldset disabled="disabled">
+    <fieldset disabled="disabled" id="form_disabled_fieldset">
       <legend>Disabled Child</legend>
       <input name="form[disabled_fieldset_child]" id="form_disabled_fieldset_child"/>
       <select>

spec/shared_selenium_session.rb

@@ -299,5 +299,4 @@ RSpec.shared_examples "Capybara::Session" do |session, mode|
   def headless_or_remote?
     !ENV['HEADLESS'].nil? || session.driver.options[:browser] == :remote
   end
-
 end