Change `form_with` to generates ids by default

When `form_with` was introduced we disabled the automatic
generation of ids that was enabled in `form_for`. This usually
is not an good idea since labels don't work when the input
doesn't have an id and it made harder to test with Capybara.

You can still disable the automatic generation of ids setting
`config.action_view.form_with_generates_ids` to `false.`

9 files changed, 245 insertions, 225 deletions

diff --git a/actionview/CHANGELOG.md b/actionview/CHANGELOG.md
index c700cb72ec..e8198926a5 100644
--- a/actionview/CHANGELOG.md
+++ b/actionview/CHANGELOG.md
@@ -1,3 +1,14 @@
+*   Change `form_with` to generates ids by default.
+
+    When `form_with` was introduced we disabled the automatic generation of ids
+    that was enabled in `form_for`. This usually is not an good idea since labels don't work
+    when the input doesn't have an id and it made harder to test with Capybara.
+
+    You can still disable the automatic generation of ids setting `config.action_view.form_with_generates_ids`
+    to `false.`
+
+    *Nick Pezza*
+
 *   Fix issues with `field_error_proc` wrapping `optgroup` and select divider `option`.
 
     Fixes #31088
diff --git a/actionview/lib/action_view/helpers/form_helper.rb b/actionview/lib/action_view/helpers/form_helper.rb
index 6d2ace8cf8..167ad06ff5 100644
--- a/actionview/lib/action_view/helpers/form_helper.rb
+++ b/actionview/lib/action_view/helpers/form_helper.rb
@@ -478,6 +478,8 @@ module ActionView
 
       mattr_accessor :form_with_generates_remote_forms, default: true
 
+      mattr_accessor :form_with_generates_ids, default: true
+
       # Creates a form tag based on mixing URLs, scopes, or models.
       #
       #   # Using just a URL:
@@ -640,16 +642,6 @@ module ActionView
       #
       # Where <tt>@document = Document.find(params[:id])</tt>.
       #
-      # When using labels +form_with+ requires setting the id on the field being
-      # labelled:
-      #
-      #   <%= form_with(model: @post) do |form| %>
-      #     <%= form.label :title %>
-      #     <%= form.text_field :title, id: :post_title %>
-      #   <% end %>
-      #
-      # See +label+ for more on how the +for+ attribute is derived.
-      #
       # === Mixing with other form helpers
       #
       # While +form_with+ uses a FormBuilder object it's possible to mix and
@@ -746,7 +738,6 @@ module ActionView
       #   end
       def form_with(model: nil, scope: nil, url: nil, format: nil, **options)
         options[:allow_method_names_outside_object] = true
-        options[:skip_default_ids] = true
 
         if model
           url ||= polymorphic_path(model, format: format)
@@ -1044,16 +1035,6 @@ module ActionView
       # or model is yielded, so any generated field names are prefixed with
       # either the passed scope or the scope inferred from the <tt>:model</tt>.
       #
-      # When using labels +fields+ requires setting the id on the field being
-      # labelled:
-      #
-      #   <%= fields :comment do |fields| %>
-      #     <%= fields.label :body %>
-      #     <%= fields.text_field :body, id: :comment_body %>
-      #   <% end %>
-      #
-      # See +label+ for more on how the +for+ attribute is derived.
-      #
       # === Mixing with other form helpers
       #
       # While +form_with+ uses a FormBuilder object it's possible to mix and
@@ -1072,7 +1053,6 @@ module ActionView
       # FormOptionsHelper#collection_select and DateHelper#datetime_select.
       def fields(scope = nil, model: nil, **options, &block)
         options[:allow_method_names_outside_object] = true
-        options[:skip_default_ids] = true
 
         if model
           scope ||= model_name_from_record_or_class(model).param_key
@@ -1676,7 +1656,7 @@ module ActionView
       def initialize(object_name, object, template, options)
         @nested_child_index = {}
         @object_name, @object, @template, @options = object_name, object, template, options
-        @default_options = @options ? @options.slice(:index, :namespace, :skip_default_ids, :allow_method_names_outside_object) : {}
+        @default_options = @options ? @options.slice(:index, :namespace, :allow_method_names_outside_object) : {}
 
         convert_to_legacy_options(@options)
 
@@ -1985,7 +1965,6 @@ module ActionView
       # See the docs for the <tt>ActionView::FormHelper.fields</tt> helper method.
       def fields(scope = nil, model: nil, **options, &block)
         options[:allow_method_names_outside_object] = true
-        options[:skip_default_ids] = true
 
         convert_to_legacy_options(options)
 
diff --git a/actionview/lib/action_view/helpers/tags/base.rb b/actionview/lib/action_view/helpers/tags/base.rb
index 8934a9894c..a8940e71a9 100644
--- a/actionview/lib/action_view/helpers/tags/base.rb
+++ b/actionview/lib/action_view/helpers/tags/base.rb
@@ -15,7 +15,6 @@ module ActionView
 
           @object_name.sub!(/\[\]$/, "") || @object_name.sub!(/\[\]\]$/, "]")
           @object = retrieve_object(options.delete(:object))
-          @skip_default_ids = options.delete(:skip_default_ids)
           @allow_method_names_outside_object = options.delete(:allow_method_names_outside_object)
           @options = options
 
@@ -97,7 +96,7 @@ module ActionView
             index = name_and_id_index(options)
             options["name"] = options.fetch("name") { tag_name(options["multiple"], index) }
 
-            unless skip_default_ids?
+            if generate_ids?
               options["id"] = options.fetch("id") { tag_id(index) }
               if namespace = options.delete("namespace")
                 options["id"] = options["id"] ? "#{namespace}_#{options['id']}" : namespace
@@ -183,8 +182,8 @@ module ActionView
             end
           end
 
-          def skip_default_ids?
-            @skip_default_ids
+          def generate_ids?
+            ActionView::Helpers::FormHelper.form_with_generates_ids
           end
       end
     end
diff --git a/actionview/lib/action_view/helpers/tags/collection_check_boxes.rb b/actionview/lib/action_view/helpers/tags/collection_check_boxes.rb
index 455442178e..021a6c0c0c 100644
--- a/actionview/lib/action_view/helpers/tags/collection_check_boxes.rb
+++ b/actionview/lib/action_view/helpers/tags/collection_check_boxes.rb
@@ -12,7 +12,6 @@ module ActionView
           def check_box(extra_html_options = {})
             html_options = extra_html_options.merge(@input_html_options)
             html_options[:multiple] = true
-            html_options[:skip_default_ids] = false
             @template_object.check_box(@object_name, @method_name, html_options, @value, nil)
           end
         end
diff --git a/actionview/lib/action_view/helpers/tags/collection_radio_buttons.rb b/actionview/lib/action_view/helpers/tags/collection_radio_buttons.rb
index 16d37134e5..b25e124a15 100644
--- a/actionview/lib/action_view/helpers/tags/collection_radio_buttons.rb
+++ b/actionview/lib/action_view/helpers/tags/collection_radio_buttons.rb
@@ -11,7 +11,6 @@ module ActionView
         class RadioButtonBuilder < Builder # :nodoc:
           def radio_button(extra_html_options = {})
             html_options = extra_html_options.merge(@input_html_options)
-            html_options[:skip_default_ids] = false
             @template_object.radio_button(@object_name, @method_name, @value, html_options)
           end
         end
diff --git a/actionview/lib/action_view/helpers/tags/label.rb b/actionview/lib/action_view/helpers/tags/label.rb
index 56b48bbd62..02bd099784 100644
--- a/actionview/lib/action_view/helpers/tags/label.rb
+++ b/actionview/lib/action_view/helpers/tags/label.rb
@@ -75,10 +75,6 @@ module ActionView
           def render_component(builder)
             builder.translation
           end
-
-          def skip_default_ids?
-            false # The id is used as the `for` attribute.
-          end
       end
     end
   end
diff --git a/actionview/lib/action_view/helpers/tags/select.rb b/actionview/lib/action_view/helpers/tags/select.rb
index 345484ba92..fcb2d49bc3 100644
--- a/actionview/lib/action_view/helpers/tags/select.rb
+++ b/actionview/lib/action_view/helpers/tags/select.rb
@@ -8,7 +8,7 @@ module ActionView
           @choices = block_given? ? template_object.capture { yield || "" } : choices
           @choices = @choices.to_a if @choices.is_a?(Range)
 
-          @html_options = html_options.except(:skip_default_ids, :allow_method_names_outside_object)
+          @html_options = html_options.except(:allow_method_names_outside_object)
 
           super(object_name, method_name, template_object, options)
         end
diff --git a/actionview/lib/action_view/railtie.rb b/actionview/lib/action_view/railtie.rb
index b22347c55c..6ac332acbb 100644
--- a/actionview/lib/action_view/railtie.rb
+++ b/actionview/lib/action_view/railtie.rb
@@ -28,6 +28,15 @@ module ActionView
       end
     end
 
+    initializer "action_view.form_with_generates_ids" do |app|
+      ActiveSupport.on_load(:action_view) do
+        form_with_generates_ids = app.config.action_view.delete(:form_with_generates_ids)
+        unless form_with_generates_ids.nil?
+          ActionView::Helpers::FormHelper.form_with_generates_ids = form_with_generates_ids
+        end
+      end
+    end
+
     initializer "action_view.logger" do
       ActiveSupport.on_load(:action_view) { self.logger ||= Rails.logger }
     end
diff --git a/actionview/test/template/form_helper/form_with_test.rb b/actionview/test/template/form_helper/form_with_test.rb
index c7d49070ce..ad23d31d41 100644
--- a/actionview/test/template/form_helper/form_with_test.rb
+++ b/actionview/test/template/form_helper/form_with_test.rb
@@ -314,17 +314,45 @@ class FormWithActsLikeFormForTest < FormWithTest
 
     expected = whole_form("/posts/123", "create-post", method: "patch") do
       "<label for='post_title'>The Title</label>" \
+      "<input name='post[title]' type='text' value='Hello World' id='post_title' />" \
+      "<textarea name='post[body]' id='post_body'>\nBack to the hill and over it again!</textarea>" \
+      "<input name='post[secret]' type='hidden' value='0' />" \
+      "<input name='post[secret]' checked='checked' type='checkbox' value='1' id='post_secret' />" \
+      "<select name='post[category]' id='post_category'><option value='animal'>animal</option>\n<option value='economy'>economy</option>\n<option value='sports'>sports</option></select>" \
+      "<input name='commit' data-disable-with='Create post' type='submit' value='Create post' />" \
+      "<button name='button' type='submit'>Create post</button>" \
+      "<button name='button' type='submit'><span>Create post</span></button>"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_with_not_outputting_ids
+    old_value = ActionView::Helpers::FormHelper.form_with_generates_ids
+    ActionView::Helpers::FormHelper.form_with_generates_ids = false
+
+    form_with(model: @post, id: "create-post") do |f|
+      concat f.label(:title) { "The Title" }
+      concat f.text_field(:title)
+      concat f.text_area(:body)
+      concat f.check_box(:secret)
+      concat f.select(:category, %w( animal economy sports ))
+      concat f.submit("Create post")
+    end
+
+    expected = whole_form("/posts/123", "create-post", method: "patch") do
+      "<label>The Title</label>" \
       "<input name='post[title]' type='text' value='Hello World' />" \
       "<textarea name='post[body]'>\nBack to the hill and over it again!</textarea>" \
       "<input name='post[secret]' type='hidden' value='0' />" \
       "<input name='post[secret]' checked='checked' type='checkbox' value='1' />" \
       "<select name='post[category]'><option value='animal'>animal</option>\n<option value='economy'>economy</option>\n<option value='sports'>sports</option></select>" \
-      "<input name='commit' data-disable-with='Create post' type='submit' value='Create post' />" \
-      "<button name='button' type='submit'>Create post</button>" \
-      "<button name='button' type='submit'><span>Create post</span></button>"
+      "<input name='commit' data-disable-with='Create post' type='submit' value='Create post' />"
     end
 
     assert_dom_equal expected, output_buffer
+  ensure
+    ActionView::Helpers::FormHelper.form_with_generates_ids = old_value
   end
 
   def test_form_with_only_url_on_create
@@ -335,7 +363,7 @@ class FormWithActsLikeFormForTest < FormWithTest
 
     expected = whole_form("/posts") do
       '<label for="title">Label me</label>' \
-      '<input type="text" name="title">'
+      '<input type="text" name="title" id="title">'
     end
 
     assert_dom_equal expected, output_buffer
@@ -349,7 +377,7 @@ class FormWithActsLikeFormForTest < FormWithTest
 
     expected = whole_form("/posts/123") do
       '<label for="title">Label me</label>' \
-      '<input type="text" name="title">'
+      '<input type="text" name="title" id="title">'
     end
 
     assert_dom_equal expected, output_buffer
@@ -361,7 +389,7 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     expected = whole_form("/posts/123") do
-      '<input type="text" name="no_model_to_back_this_badboy">'
+      '<input type="text" name="no_model_to_back_this_badboy" id="no_model_to_back_this_badboy" >'
     end
 
     assert_dom_equal expected, output_buffer
@@ -373,7 +401,7 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     expected = whole_form("/posts/123", method: :patch) do
-      '<input type="text" name="post[this_dont_exist_on_post]">'
+      '<input type="text" name="post[this_dont_exist_on_post]" id="post_this_dont_exist_on_post" >'
     end
 
     assert_dom_equal expected, output_buffer
@@ -391,8 +419,8 @@ class FormWithActsLikeFormForTest < FormWithTest
     end.new
 
     form_with(model: obj, scope: "other_name", url: "/", id: "edit-other-name") do |f|
-      assert_dom_equal '<input type="hidden" name="other_name[private_property]">', f.hidden_field(:private_property)
-      assert_dom_equal '<input type="hidden" name="other_name[protected_property]">', f.hidden_field(:protected_property)
+      assert_dom_equal '<input type="hidden" name="other_name[private_property]" id="other_name_private_property">', f.hidden_field(:private_property)
+      assert_dom_equal '<input type="hidden" name="other_name[protected_property]"  id="other_name_protected_property">', f.hidden_field(:protected_property)
     end
   end
 
@@ -459,7 +487,7 @@ class FormWithActsLikeFormForTest < FormWithTest
       "<label for='post_active_false'>" \
       "<input checked='checked' name='post[active]' type='radio' value='false' id='post_active_false' />" \
       "false</label>" \
-      "<input name='post[id]' type='hidden' value='1' />"
+      "<input name='post[id]' type='hidden' value='1' id='post_id' />"
     end
 
     assert_dom_equal expected, output_buffer
@@ -557,7 +585,7 @@ class FormWithActsLikeFormForTest < FormWithTest
       "<label for='post_tag_ids_3'>" \
       "<input checked='checked' name='post[tag_ids][]' type='checkbox' value='3' id='post_tag_ids_3' />" \
       "Tag 3</label>" \
-      "<input name='post[id]' type='hidden' value='1' />"
+      "<input name='post[id]' type='hidden' value='1' id='post_id' />"
     end
 
     assert_dom_equal expected, output_buffer
@@ -587,7 +615,7 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     expected = whole_form("/posts/123", "create-post", method: "patch", multipart: true) do
-      "<input name='post[file]' type='file' />"
+      "<input name='post[file]' type='file' id='post_file' />"
     end
 
     assert_dom_equal expected, output_buffer
@@ -601,7 +629,7 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     expected = whole_form("/posts/123", method: "patch", multipart: true) do
-      "<input name='post[comment][file]' type='file' />"
+      "<input name='post[comment][file]' type='file' id='post_comment_file'/>"
     end
 
     assert_dom_equal expected, output_buffer
@@ -640,7 +668,7 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     expected = whole_form("/posts/44", method: "patch") do
-      "<input name='post[title]' type='text' value='And his name will be forty and four.' />" \
+      "<input name='post[title]' type='text' value='And his name will be forty and four.' id='post_title' />" \
       "<input name='commit' data-disable-with='Edit post' type='submit' value='Edit post' />"
     end
 
@@ -658,10 +686,10 @@ class FormWithActsLikeFormForTest < FormWithTest
 
     expected = whole_form("/posts/123", "create-post", method: "patch") do
       "<label for='other_name_title' class='post_title'>Title</label>" \
-      "<input name='other_name[title]' value='Hello World' type='text' />" \
-      "<textarea name='other_name[body]'>\nBack to the hill and over it again!</textarea>" \
+      "<input name='other_name[title]' value='Hello World' type='text' id='other_name_title' />" \
+      "<textarea name='other_name[body]' id='other_name_body'>\nBack to the hill and over it again!</textarea>" \
       "<input name='other_name[secret]' value='0' type='hidden' />" \
-      "<input name='other_name[secret]' checked='checked' value='1' type='checkbox' />" \
+      "<input name='other_name[secret]' checked='checked' value='1' type='checkbox' id='other_name_secret' />" \
       "<input name='commit' value='Create post' data-disable-with='Create post' type='submit' />"
     end
 
@@ -676,10 +704,10 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     expected = whole_form("/", "create-post", method: "delete") do
-      "<input name='post[title]' type='text' value='Hello World' />" \
-      "<textarea name='post[body]'>\nBack to the hill and over it again!</textarea>" \
+      "<input name='post[title]' type='text' value='Hello World' id='post_title' />" \
+      "<textarea name='post[body]' id='post_body'>\nBack to the hill and over it again!</textarea>" \
       "<input name='post[secret]' type='hidden' value='0' />" \
-      "<input name='post[secret]' checked='checked' type='checkbox' value='1' />"
+      "<input name='post[secret]' checked='checked' type='checkbox' value='1' id='post_secret'/>"
     end
 
     assert_dom_equal expected, output_buffer
@@ -693,10 +721,10 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     expected = whole_form("/", "create-post", method: "delete") do
-      "<input name='post[title]' type='text' value='Hello World' />" \
-      "<textarea name='post[body]'>\nBack to the hill and over it again!</textarea>" \
+      "<input name='post[title]' type='text' value='Hello World' id='post_title' />" \
+      "<textarea name='post[body]' id='post_body' >\nBack to the hill and over it again!</textarea>" \
       "<input name='post[secret]' type='hidden' value='0' />" \
-      "<input name='post[secret]' checked='checked' type='checkbox' value='1' />"
+      "<input name='post[secret]' checked='checked' type='checkbox' value='1' id='post_secret' />"
     end
 
     assert_dom_equal expected, output_buffer
@@ -710,7 +738,7 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     expected = whole_form("/search", "search-post", method: "get") do
-      "<input name='post[title]' type='search' />"
+      "<input name='post[title]' type='search' id='post_title' />"
     end
 
     assert_dom_equal expected, output_buffer
@@ -724,10 +752,10 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     expected = whole_form("/", "create-post", method: "patch") do
-      "<input name='post[title]' type='text' value='Hello World' />" \
-      "<textarea name='post[body]'>\nBack to the hill and over it again!</textarea>" \
+      "<input name='post[title]' type='text' value='Hello World' id='post_title' />" \
+      "<textarea name='post[body]' id='post_body' >\nBack to the hill and over it again!</textarea>" \
       "<input name='post[secret]' type='hidden' value='0' />" \
-      "<input name='post[secret]' checked='checked' type='checkbox' value='1' />"
+      "<input name='post[secret]' checked='checked' type='checkbox' value='1' id='post_secret' />"
     end
 
     assert_dom_equal expected, output_buffer
@@ -744,10 +772,10 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     expected = whole_form("/", "create-post", method: "patch", local: true) do
-      "<input name='post[title]' type='text' value='Hello World' />" \
-      "<textarea name='post[body]'>\nBack to the hill and over it again!</textarea>" \
+      "<input name='post[title]' type='text' value='Hello World' id='post_title' />" \
+      "<textarea name='post[body]' id='post_body'>\nBack to the hill and over it again!</textarea>" \
       "<input name='post[secret]' type='hidden' value='0' />" \
-      "<input name='post[secret]' checked='checked' type='checkbox' value='1' />"
+      "<input name='post[secret]' checked='checked' type='checkbox' value='1' id='post_secret' />"
     end
 
     assert_dom_equal expected, output_buffer
@@ -761,7 +789,7 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     expected = whole_form("/", skip_enforcing_utf8: true) do
-      "<input name='post[title]' type='text' value='Hello World' />"
+      "<input name='post[title]' type='text' value='Hello World' id='post_title' />"
     end
 
     assert_dom_equal expected, output_buffer
@@ -773,7 +801,7 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     expected = whole_form("/", skip_enforcing_utf8: false) do
-      "<input name='post[title]' type='text' value='Hello World' />"
+      "<input name='post[title]' type='text' value='Hello World' id='post_title' />"
     end
 
     assert_dom_equal expected, output_buffer
@@ -787,10 +815,10 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     expected = whole_form("/", "create-post") do
-      "<input name='post[title]' type='text' value='Hello World' />" \
-      "<textarea name='post[body]'>\nBack to the hill and over it again!</textarea>" \
+      "<input name='post[title]' type='text' value='Hello World' id='post_title' />" \
+      "<textarea name='post[body]' id='post_body' >\nBack to the hill and over it again!</textarea>" \
       "<input name='post[secret]' type='hidden' value='0' />" \
-      "<input name='post[secret]' checked='checked' type='checkbox' value='1' />"
+      "<input name='post[secret]' checked='checked' type='checkbox' value='1' id='post_secret' />"
     end
 
     assert_dom_equal expected, output_buffer
@@ -806,10 +834,10 @@ class FormWithActsLikeFormForTest < FormWithTest
 
     expected = whole_form("/posts/123", method: "patch") do
       "<label for='post_123_title'>Title</label>" \
-      "<input name='post[123][title]' type='text' value='Hello World' />" \
-      "<textarea name='post[123][body]'>\nBack to the hill and over it again!</textarea>" \
+      "<input name='post[123][title]' type='text' value='Hello World' id='post_123_title' />" \
+      "<textarea name='post[123][body]' id='post_123_body'>\nBack to the hill and over it again!</textarea>" \
       "<input name='post[123][secret]' type='hidden' value='0' />" \
-      "<input name='post[123][secret]' checked='checked' type='checkbox' value='1' />"
+      "<input name='post[123][secret]' checked='checked' type='checkbox' value='1' id='post_123_secret' />"
     end
 
     assert_dom_equal expected, output_buffer
@@ -823,10 +851,10 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     expected = whole_form("/posts/123", method: "patch") do
-      "<input name='post[][title]' type='text' value='Hello World' />" \
-      "<textarea name='post[][body]'>\nBack to the hill and over it again!</textarea>" \
+      "<input name='post[][title]' type='text' value='Hello World' id='post__title' />" \
+      "<textarea name='post[][body]' id='post__body' >\nBack to the hill and over it again!</textarea>" \
       "<input name='post[][secret]' type='hidden' value='0' />" \
-      "<input name='post[][secret]' checked='checked' type='checkbox' value='1' />"
+      "<input name='post[][secret]' checked='checked' type='checkbox' value='1' id='post__secret' />"
     end
 
     assert_dom_equal expected, output_buffer
@@ -841,7 +869,7 @@ class FormWithActsLikeFormForTest < FormWithTest
 
     expected = whole_form("/posts/123", method: "patch") do
       "<div class='field_with_errors'><label for='post_author_name' class='label'>Author name</label></div>" \
-      "<div class='field_with_errors'><input name='post[author_name]' type='text' value='' /></div>" \
+      "<div class='field_with_errors'><input name='post[author_name]' type='text' value='' id='post_author_name' /></div>" \
       "<input name='commit' data-disable-with='Create post' type='submit' value='Create post' />"
     end
 
@@ -859,7 +887,7 @@ class FormWithActsLikeFormForTest < FormWithTest
 
     expected = whole_form("/posts/123", method: "patch") do
       "<div class='field_with_errors'><label for='post_author_name' class='label'>Author name</label></div>" \
-      "<div class='field_with_errors'><input name='post[author_name]' type='text' value='' /></div>" \
+      "<div class='field_with_errors'><input name='post[author_name]' type='text' value='' id='post_author_name' /></div>" \
       "<input name='commit' data-disable-with='Create post' type='submit' value='Create post' />"
     end
 
@@ -947,7 +975,7 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     expected = whole_form("/posts/123", method: :patch) do
-      '<input type="text" name="post[comment][dont_exist_on_model]">'
+      '<input type="text" name="post[comment][dont_exist_on_model]" id="post_comment_dont_exist_on_model" >'
     end
 
     assert_dom_equal expected, output_buffer
@@ -967,7 +995,7 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     expected = whole_form do
-      '<input name="posts[post][0][comment][1][dont_exist_on_model]" type="text">'
+      '<input name="posts[post][0][comment][1][dont_exist_on_model]" type="text" id="posts_post_0_comment_1_dont_exist_on_model" >'
     end
 
     assert_dom_equal expected, output_buffer
@@ -982,7 +1010,7 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     expected = whole_form("/posts/123", method: "patch") do
-      "<input name='post[comment][body]' type='text' value='Hello World' />"
+      "<input name='post[comment][body]' type='text' value='Hello World' id='post_comment_body' />"
     end
 
     assert_dom_equal expected, output_buffer
@@ -1002,7 +1030,7 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     expected = whole_form do
-      "<input name='posts[post][0][comment][1][name]' type='text' value='comment #1' />"
+      "<input name='posts[post][0][comment][1][name]' type='text' value='comment #1' id='posts_post_0_comment_1_name' />"
     end
 
     assert_dom_equal expected, output_buffer
@@ -1017,8 +1045,8 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     expected = whole_form("/posts/123", method: "patch") do
-      "<input name='post[123][title]' type='text' value='Hello World' />" \
-      "<input name='post[123][comment][][name]' type='text' value='new comment' />"
+      "<input name='post[123][title]' type='text' value='Hello World' id='post_123_title' />" \
+      "<input name='post[123][comment][][name]' type='text' value='new comment' id='post_123_comment__name' />"
     end
 
     assert_dom_equal expected, output_buffer
@@ -1033,8 +1061,8 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     expected = whole_form("/posts/123", method: "patch") do
-      "<input name='post[1][title]' type='text' value='Hello World' />" \
-      "<input name='post[1][comment][1][name]' type='text' value='new comment' />"
+      "<input name='post[1][title]' type='text' value='Hello World' id='post_1_title' />" \
+      "<input name='post[1][comment][1][name]' type='text' value='new comment' id='post_1_comment_1_name' />"
     end
 
     assert_dom_equal expected, output_buffer
@@ -1048,7 +1076,7 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     expected = whole_form("/posts/123", method: "patch") do
-      "<input name='post[1][comment][title]' type='text' value='Hello World' />"
+      "<input name='post[1][comment][title]' type='text' value='Hello World' id='post_1_comment_title' />"
     end
 
     assert_dom_equal expected, output_buffer
@@ -1062,7 +1090,7 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     expected = whole_form("/posts/123", method: "patch") do
-      "<input name='post[1][comment][5][title]' type='text' value='Hello World' />"
+      "<input name='post[1][comment][5][title]' type='text' value='Hello World' id='post_1_comment_5_title' />"
     end
 
     assert_dom_equal expected, output_buffer
@@ -1076,7 +1104,7 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     expected = whole_form("/posts/123", method: "patch") do
-      "<input name='post[123][comment][title]' type='text' value='Hello World' />"
+      "<input name='post[123][comment][title]' type='text' value='Hello World' id='post_123_comment_title' />"
     end
 
     assert_dom_equal expected, output_buffer
@@ -1090,7 +1118,7 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     expected = whole_form("/posts/123", method: "patch") do
-      "<input name='post[comment][5][title]' type='radio' value='hello' />"
+      "<input name='post[comment][5][title]' type='radio' value='hello' id='post_comment_5_title_hello' />"
     end
 
     assert_dom_equal expected, output_buffer
@@ -1104,7 +1132,7 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     expected = whole_form("/posts/123", method: "patch") do
-      "<input name='post[123][comment][123][title]' type='text' value='Hello World' />"
+      "<input name='post[123][comment][123][title]' type='text' value='Hello World' id='post_123_comment_123_title' />"
     end
 
     assert_dom_equal expected, output_buffer
@@ -1124,9 +1152,9 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     expected = whole_form("/posts/123", method: "patch") do
-      "<input name='post[123][comment][5][title]' type='text' value='Hello World' />"
+      "<input name='post[123][comment][5][title]' type='text' value='Hello World' id='post_123_comment_5_title' />"
     end + whole_form("/posts/123", method: "patch") do
-      "<input name='post[1][comment][123][title]' type='text' value='Hello World' />"
+      "<input name='post[1][comment][123][title]' type='text' value='Hello World' id='post_1_comment_123_title' />"
     end
 
     assert_dom_equal expected, output_buffer
@@ -1143,8 +1171,8 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     expected = whole_form("/posts/123", method: "patch") do
-      '<input name="post[title]" type="text" value="Hello World" />' \
-        '<input name="post[author_attributes][name]" type="text" value="new author" />'
+      '<input name="post[title]" type="text" value="Hello World" id="post_title" />' \
+        '<input name="post[author_attributes][name]" type="text" value="new author" id="post_author_attributes_name" />'
     end
 
     assert_dom_equal expected, output_buffer
@@ -1170,9 +1198,9 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     expected = whole_form("/posts/123", method: "patch") do
-      '<input name="post[title]" type="text" value="Hello World" />' \
-      '<input name="post[author_attributes][name]" type="text" value="author #321" />' \
-      '<input name="post[author_attributes][id]" type="hidden" value="321" />'
+      '<input name="post[title]" type="text" value="Hello World" id="post_title" />' \
+      '<input name="post[author_attributes][name]" type="text" value="author #321" id="post_author_attributes_name" />' \
+      '<input name="post[author_attributes][id]" type="hidden" value="321" id="post_author_attributes_id" />'
     end
 
     assert_dom_equal expected, output_buffer
@@ -1189,9 +1217,9 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     expected = whole_form("/posts/123", method: "patch") do
-      '<input name="post[title]" type="text" value="Hello World" />' \
-      '<input name="post[author_attributes][name]" type="text" value="author #321" />' \
-      '<input name="post[author_attributes][id]" type="hidden" value="321" />'
+      '<input name="post[title]" type="text" value="Hello World" id="post_title" />' \
+      '<input name="post[author_attributes][name]" type="text" value="author #321" id="post_author_attributes_name" />' \
+      '<input name="post[author_attributes][id]" type="hidden" value="321" id="post_author_attributes_id" />'
     end
 
     assert_dom_equal expected, output_buffer
@@ -1208,8 +1236,8 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     expected = whole_form("/posts/123", method: "patch") do
-      '<input name="post[title]" type="text" value="Hello World" />' \
-      '<input name="post[author_attributes][name]" type="text" value="author #321" />'
+      '<input name="post[title]" type="text" value="Hello World" id="post_title" />' \
+      '<input name="post[author_attributes][name]" type="text" value="author #321" id="post_author_attributes_name" />'
     end
 
     assert_dom_equal expected, output_buffer
@@ -1226,8 +1254,8 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     expected = whole_form("/posts/123", method: "patch") do
-      '<input name="post[title]" type="text" value="Hello World" />' \
-      '<input name="post[author_attributes][name]" type="text" value="author #321" />'
+      '<input name="post[title]" type="text" value="Hello World" id="post_title" />' \
+      '<input name="post[author_attributes][name]" type="text" value="author #321" id="post_author_attributes_name" />'
     end
 
     assert_dom_equal expected, output_buffer
@@ -1244,9 +1272,9 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     expected = whole_form("/posts/123", method: "patch") do
-      '<input name="post[title]" type="text" value="Hello World" />' \
-      '<input name="post[author_attributes][name]" type="text" value="author #321" />' \
-      '<input name="post[author_attributes][id]" type="hidden" value="321" />'
+      '<input name="post[title]" type="text" value="Hello World" id="post_title" />' \
+      '<input name="post[author_attributes][name]" type="text" value="author #321" id="post_author_attributes_name" />' \
+      '<input name="post[author_attributes][id]" type="hidden" value="321" id="post_author_attributes_id" />'
     end
 
     assert_dom_equal expected, output_buffer
@@ -1264,9 +1292,9 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     expected = whole_form("/posts/123", method: "patch") do
-      '<input name="post[title]" type="text" value="Hello World" />' \
-      '<input name="post[author_attributes][id]" type="hidden" value="321" />' \
-      '<input name="post[author_attributes][name]" type="text" value="author #321" />'
+      '<input name="post[title]" type="text" value="Hello World" id="post_title" />' \
+      '<input name="post[author_attributes][id]" type="hidden" value="321" id="post_author_attributes_id" />' \
+      '<input name="post[author_attributes][name]" type="text" value="author #321" id="post_author_attributes_name" />'
     end
 
     assert_dom_equal expected, output_buffer
@@ -1285,11 +1313,11 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     expected = whole_form("/posts/123", method: "patch") do
-      '<input name="post[title]" type="text" value="Hello World" />' \
-      '<input name="post[comments_attributes][0][name]" type="text" value="comment #1" />' \
-      '<input name="post[comments_attributes][0][id]" type="hidden" value="1" />' \
-      '<input name="post[comments_attributes][1][name]" type="text" value="comment #2" />' \
-      '<input name="post[comments_attributes][1][id]" type="hidden" value="2" />'
+      '<input name="post[title]" type="text" value="Hello World" id="post_title" />' \
+      '<input name="post[comments_attributes][0][name]" type="text" value="comment #1" id="post_comments_attributes_0_name" />' \
+      '<input name="post[comments_attributes][0][id]" type="hidden" value="1" id="post_comments_attributes_0_id" />' \
+      '<input name="post[comments_attributes][1][name]" type="text" value="comment #2" id="post_comments_attributes_1_name" />' \
+      '<input name="post[comments_attributes][1][id]" type="hidden" value="2" id="post_comments_attributes_1_id" />'
     end
 
     assert_dom_equal expected, output_buffer
@@ -1312,11 +1340,11 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     expected = whole_form("/posts/123", method: "patch") do
-      '<input name="post[title]" type="text" value="Hello World" />' \
-      '<input name="post[author_attributes][name]" type="text" value="author #321" />' \
-      '<input name="post[author_attributes][id]" type="hidden" value="321" />' \
-      '<input name="post[comments_attributes][0][name]" type="text" value="comment #1" />' \
-      '<input name="post[comments_attributes][1][name]" type="text" value="comment #2" />'
+      '<input name="post[title]" type="text" value="Hello World" id="post_title" />' \
+      '<input name="post[author_attributes][name]" type="text" value="author #321" id="post_author_attributes_name" />' \
+      '<input name="post[author_attributes][id]" type="hidden" value="321" id="post_author_attributes_id" />' \
+      '<input name="post[comments_attributes][0][name]" type="text" value="comment #1" id="post_comments_attributes_0_name" />' \
+      '<input name="post[comments_attributes][1][name]" type="text" value="comment #2" id="post_comments_attributes_1_name" />'
     end
 
     assert_dom_equal expected, output_buffer
@@ -1339,10 +1367,10 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     expected = whole_form("/posts/123", method: "patch") do
-      '<input name="post[title]" type="text" value="Hello World" />' \
-      '<input name="post[author_attributes][name]" type="text" value="author #321" />' \
-      '<input name="post[comments_attributes][0][name]" type="text" value="comment #1" />' \
-      '<input name="post[comments_attributes][1][name]" type="text" value="comment #2" />'
+      '<input name="post[title]" type="text" value="Hello World" id="post_title" />' \
+      '<input name="post[author_attributes][name]" type="text" value="author #321" id="post_author_attributes_name" />' \
+      '<input name="post[comments_attributes][0][name]" type="text" value="comment #1" id="post_comments_attributes_0_name" />' \
+      '<input name="post[comments_attributes][1][name]" type="text" value="comment #2" id="post_comments_attributes_1_name" />'
     end
 
     assert_dom_equal expected, output_buffer
@@ -1365,11 +1393,11 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     expected = whole_form("/posts/123", method: "patch") do
-      '<input name="post[title]" type="text" value="Hello World" />' \
-      '<input name="post[author_attributes][name]" type="text" value="author #321" />' \
-      '<input name="post[author_attributes][id]" type="hidden" value="321" />' \
-      '<input name="post[comments_attributes][0][name]" type="text" value="comment #1" />' \
-      '<input name="post[comments_attributes][1][name]" type="text" value="comment #2" />'
+      '<input name="post[title]" type="text" value="Hello World" id="post_title" />' \
+      '<input name="post[author_attributes][name]" type="text" value="author #321" id="post_author_attributes_name" />' \
+      '<input name="post[author_attributes][id]" type="hidden" value="321" id="post_author_attributes_id" />' \
+      '<input name="post[comments_attributes][0][name]" type="text" value="comment #1" id="post_comments_attributes_0_name" />' \
+      '<input name="post[comments_attributes][1][name]" type="text" value="comment #2" id="post_comments_attributes_1_name" />'
     end
 
     assert_dom_equal expected, output_buffer
@@ -1388,11 +1416,11 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     expected = whole_form("/posts/123", method: "patch") do
-      '<input name="post[title]" type="text" value="Hello World" />' \
-      '<input name="post[comments_attributes][0][name]" type="text" value="comment #1" />' \
-      '<input name="post[comments_attributes][0][id]" type="hidden" value="1" />' \
-      '<input name="post[comments_attributes][1][name]" type="text" value="comment #2" />' \
-      '<input name="post[comments_attributes][1][id]" type="hidden" value="2" />'
+      '<input name="post[title]" type="text" value="Hello World" id="post_title" />' \
+      '<input name="post[comments_attributes][0][name]" type="text" value="comment #1" id="post_comments_attributes_0_name" />' \
+      '<input name="post[comments_attributes][0][id]" type="hidden" value="1" id="post_comments_attributes_0_id" />' \
+      '<input name="post[comments_attributes][1][name]" type="text" value="comment #2" id="post_comments_attributes_1_name" />' \
+      '<input name="post[comments_attributes][1][id]" type="hidden" value="2" id="post_comments_attributes_1_id" />'
     end
 
     assert_dom_equal expected, output_buffer
@@ -1412,11 +1440,11 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     expected = whole_form("/posts/123", method: "patch") do
-      '<input name="post[title]" type="text" value="Hello World" />' \
-      '<input name="post[comments_attributes][0][id]" type="hidden" value="1" />' \
-      '<input name="post[comments_attributes][0][name]" type="text" value="comment #1" />' \
-      '<input name="post[comments_attributes][1][id]" type="hidden" value="2" />' \
-      '<input name="post[comments_attributes][1][name]" type="text" value="comment #2" />'
+      '<input name="post[title]" type="text" value="Hello World" id="post_title" />' \
+      '<input name="post[comments_attributes][0][id]" type="hidden" value="1" id="post_comments_attributes_0_id" />' \
+      '<input name="post[comments_attributes][0][name]" type="text" value="comment #1" id="post_comments_attributes_0_name" />' \
+      '<input name="post[comments_attributes][1][id]" type="hidden" value="2" id="post_comments_attributes_1_id" />' \
+      '<input name="post[comments_attributes][1][name]" type="text" value="comment #2" id="post_comments_attributes_1_name" />'
     end
 
     assert_dom_equal expected, output_buffer
@@ -1435,9 +1463,9 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     expected = whole_form("/posts/123", method: "patch") do
-      '<input name="post[title]" type="text" value="Hello World" />' \
-      '<input name="post[comments_attributes][0][name]" type="text" value="new comment" />' \
-      '<input name="post[comments_attributes][1][name]" type="text" value="new comment" />'
+      '<input name="post[title]" type="text" value="Hello World" id="post_title" />' \
+      '<input name="post[comments_attributes][0][name]" type="text" value="new comment" id="post_comments_attributes_0_name" />' \
+      '<input name="post[comments_attributes][1][name]" type="text" value="new comment" id="post_comments_attributes_1_name" />'
     end
 
     assert_dom_equal expected, output_buffer
@@ -1456,10 +1484,10 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     expected = whole_form("/posts/123", method: "patch") do
-      '<input name="post[title]" type="text" value="Hello World" />' \
-      '<input name="post[comments_attributes][0][name]" type="text" value="comment #321" />' \
-      '<input name="post[comments_attributes][0][id]" type="hidden" value="321" />' \
-      '<input name="post[comments_attributes][1][name]" type="text" value="new comment" />'
+      '<input name="post[title]" type="text" value="Hello World" id="post_title" />' \
+      '<input name="post[comments_attributes][0][name]" type="text" value="comment #321" id="post_comments_attributes_0_name" />' \
+      '<input name="post[comments_attributes][0][id]" type="hidden" value="321" id="post_comments_attributes_0_id"/>' \
+      '<input name="post[comments_attributes][1][name]" type="text" value="new comment" id="post_comments_attributes_1_name" />'
     end
 
     assert_dom_equal expected, output_buffer
@@ -1474,7 +1502,7 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     expected = whole_form("/posts/123", method: "patch") do
-      '<input name="post[title]" type="text" value="Hello World" />'
+      '<input name="post[title]" type="text" value="Hello World" id="post_title" />'
     end
 
     assert_dom_equal expected, output_buffer
@@ -1491,11 +1519,11 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     expected = whole_form("/posts/123", method: "patch") do
-      '<input name="post[title]" type="text" value="Hello World" />' \
-      '<input name="post[comments_attributes][0][name]" type="text" value="comment #1" />' \
-      '<input name="post[comments_attributes][0][id]" type="hidden" value="1" />' \
-      '<input name="post[comments_attributes][1][name]" type="text" value="comment #2" />' \
-      '<input name="post[comments_attributes][1][id]" type="hidden" value="2" />'
+      '<input name="post[title]" type="text" value="Hello World" id="post_title" />' \
+      '<input name="post[comments_attributes][0][name]" type="text" value="comment #1" id="post_comments_attributes_0_name" />' \
+      '<input name="post[comments_attributes][0][id]" type="hidden" value="1" id="post_comments_attributes_0_id" />' \
+      '<input name="post[comments_attributes][1][name]" type="text" value="comment #2" id="post_comments_attributes_1_name" />' \
+      '<input name="post[comments_attributes][1][id]" type="hidden" value="2" id="post_comments_attributes_1_id" />'
     end
 
     assert_dom_equal expected, output_buffer
@@ -1512,11 +1540,11 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     expected = whole_form("/posts/123", method: "patch") do
-      '<input name="post[title]" type="text" value="Hello World" />' \
-      '<input name="post[comments_attributes][0][name]" type="text" value="comment #1" />' \
-      '<input name="post[comments_attributes][0][id]" type="hidden" value="1" />' \
-      '<input name="post[comments_attributes][1][name]" type="text" value="comment #2" />' \
-      '<input name="post[comments_attributes][1][id]" type="hidden" value="2" />'
+      '<input name="post[title]" type="text" value="Hello World" id="post_title" />' \
+      '<input name="post[comments_attributes][0][name]" type="text" value="comment #1" id="post_comments_attributes_0_name" />' \
+      '<input name="post[comments_attributes][0][id]" type="hidden" value="1" id="post_comments_attributes_0_id" />' \
+      '<input name="post[comments_attributes][1][name]" type="text" value="comment #2" id="post_comments_attributes_1_name" />' \
+      '<input name="post[comments_attributes][1][id]" type="hidden" value="2" id="post_comments_attributes_1_id" />'
     end
 
     assert_dom_equal expected, output_buffer
@@ -1547,11 +1575,11 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     expected = whole_form("/posts/123", method: "patch") do
-      '<input name="post[title]" type="text" value="Hello World" />' \
-      '<input name="post[comments_attributes][0][name]" type="text" value="comment #1" />' \
-      '<input name="post[comments_attributes][0][id]" type="hidden" value="1" />' \
-      '<input name="post[comments_attributes][1][name]" type="text" value="comment #2" />' \
-      '<input name="post[comments_attributes][1][id]" type="hidden" value="2" />'
+      '<input name="post[title]" type="text" value="Hello World" id="post_title" />' \
+      '<input name="post[comments_attributes][0][name]" type="text" value="comment #1" id="post_comments_attributes_0_name" />' \
+      '<input name="post[comments_attributes][0][id]" type="hidden" value="1" id="post_comments_attributes_0_id" />' \
+      '<input name="post[comments_attributes][1][name]" type="text" value="comment #2" id="post_comments_attributes_1_name" />' \
+      '<input name="post[comments_attributes][1][id]" type="hidden" value="2" id="post_comments_attributes_1_id" />'
     end
 
     assert_dom_equal expected, output_buffer
@@ -1570,10 +1598,10 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     expected = whole_form("/posts/123", method: "patch") do
-      '<input name="post[title]" type="text" value="Hello World" />' \
-      '<input name="post[comments_attributes][0][name]" type="text" value="comment #321" />' \
-      '<input name="post[comments_attributes][0][id]" type="hidden" value="321" />' \
-      '<input name="post[comments_attributes][1][name]" type="text" value="new comment" />'
+      '<input name="post[title]" type="text" value="Hello World" id="post_title" />' \
+      '<input name="post[comments_attributes][0][name]" type="text" value="comment #321" id="post_comments_attributes_0_name" />' \
+      '<input name="post[comments_attributes][0][id]" type="hidden" value="321" id="post_comments_attributes_0_id" />' \
+      '<input name="post[comments_attributes][1][name]" type="text" value="new comment" id="post_comments_attributes_1_name" />'
     end
 
     assert_dom_equal expected, output_buffer
@@ -1590,8 +1618,8 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     expected = whole_form("/posts/123", method: "patch") do
-      '<input name="post[comments_attributes][abc][name]" type="text" value="comment #321" />' \
-      '<input name="post[comments_attributes][abc][id]" type="hidden" value="321" />'
+      '<input name="post[comments_attributes][abc][name]" type="text" value="comment #321" id="post_comments_attributes_abc_name" />' \
+      '<input name="post[comments_attributes][abc][id]" type="hidden" value="321" id="post_comments_attributes_abc_id" />'
     end
 
     assert_dom_equal expected, output_buffer
@@ -1607,8 +1635,8 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     expected = whole_form("/posts/123", method: "patch") do
-      '<input name="post[comments_attributes][abc][name]" type="text" value="comment #321" />' \
-      '<input name="post[comments_attributes][abc][id]" type="hidden" value="321" />'
+      '<input name="post[comments_attributes][abc][name]" type="text" value="comment #321" id="post_comments_attributes_abc_name" />' \
+      '<input name="post[comments_attributes][abc][id]" type="hidden" value="321" id="post_comments_attributes_abc_id" />'
     end
 
     assert_dom_equal expected, output_buffer
@@ -1630,8 +1658,8 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     expected = whole_form("/posts/123", method: "patch") do
-      '<input name="post[comments_attributes][abc][name]" type="text" value="comment #321" />' \
-      '<input name="post[comments_attributes][abc][id]" type="hidden" value="321" />'
+      '<input name="post[comments_attributes][abc][name]" type="text" value="comment #321" id="post_comments_attributes_abc_name" />' \
+      '<input name="post[comments_attributes][abc][id]" type="hidden" value="321" id="post_comments_attributes_abc_id" />'
     end
 
     assert_dom_equal expected, output_buffer
@@ -1716,18 +1744,18 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     expected = whole_form("/posts/123", method: "patch") do
-      '<input name="post[comments_attributes][0][name]" type="text" value="comment #321" />' \
-      '<input name="post[comments_attributes][0][relevances_attributes][0][value]" type="text" value="commentrelevance #314" />' \
-      '<input name="post[comments_attributes][0][relevances_attributes][0][id]" type="hidden" value="314" />' \
-      '<input name="post[comments_attributes][0][id]" type="hidden" value="321" />' \
-      '<input name="post[tags_attributes][0][value]" type="text" value="tag #123" />' \
-      '<input name="post[tags_attributes][0][relevances_attributes][0][value]" type="text" value="tagrelevance #3141" />' \
-      '<input name="post[tags_attributes][0][relevances_attributes][0][id]" type="hidden" value="3141" />' \
-      '<input name="post[tags_attributes][0][id]" type="hidden" value="123" />' \
-      '<input name="post[tags_attributes][1][value]" type="text" value="tag #456" />' \
-      '<input name="post[tags_attributes][1][relevances_attributes][0][value]" type="text" value="tagrelevance #31415" />' \
-      '<input name="post[tags_attributes][1][relevances_attributes][0][id]" type="hidden" value="31415" />' \
-      '<input name="post[tags_attributes][1][id]" type="hidden" value="456" />'
+      '<input name="post[comments_attributes][0][name]" type="text" value="comment #321" id="post_comments_attributes_0_name" />' \
+      '<input name="post[comments_attributes][0][relevances_attributes][0][value]" type="text" value="commentrelevance #314" id="post_comments_attributes_0_relevances_attributes_0_value" />' \
+      '<input name="post[comments_attributes][0][relevances_attributes][0][id]" type="hidden" value="314" id="post_comments_attributes_0_relevances_attributes_0_id"/>' \
+      '<input name="post[comments_attributes][0][id]" type="hidden" value="321" id="post_comments_attributes_0_id"/>' \
+      '<input name="post[tags_attributes][0][value]" type="text" value="tag #123" id="post_tags_attributes_0_value"/>' \
+      '<input name="post[tags_attributes][0][relevances_attributes][0][value]" type="text" value="tagrelevance #3141" id="post_tags_attributes_0_relevances_attributes_0_value"/>' \
+      '<input name="post[tags_attributes][0][relevances_attributes][0][id]" type="hidden" value="3141" id="post_tags_attributes_0_relevances_attributes_0_id"/>' \
+      '<input name="post[tags_attributes][0][id]" type="hidden" value="123" id="post_tags_attributes_0_id"/>' \
+      '<input name="post[tags_attributes][1][value]" type="text" value="tag #456" id="post_tags_attributes_1_value"/>' \
+      '<input name="post[tags_attributes][1][relevances_attributes][0][value]" type="text" value="tagrelevance #31415" id="post_tags_attributes_1_relevances_attributes_0_value"/>' \
+      '<input name="post[tags_attributes][1][relevances_attributes][0][id]" type="hidden" value="31415" id="post_tags_attributes_1_relevances_attributes_0_id"/>' \
+      '<input name="post[tags_attributes][1][id]" type="hidden" value="456" id="post_tags_attributes_1_id"/>'
     end
 
     assert_dom_equal expected, output_buffer
@@ -1743,7 +1771,7 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     expected = whole_form("/posts/123", method: "patch") do
-      '<input name="post[author_attributes][name]" type="text" value="hash backed author" />'
+      '<input name="post[author_attributes][name]" type="text" value="hash backed author" id="post_author_attributes_name" />'
     end
 
     assert_dom_equal expected, output_buffer
@@ -1757,10 +1785,10 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     expected =
-      "<input name='post[title]' type='text' value='Hello World' />" \
-      "<textarea name='post[body]'>\nBack to the hill and over it again!</textarea>" \
+      "<input name='post[title]' type='text' value='Hello World' id='post_title' />" \
+      "<textarea name='post[body]' id='post_body'>\nBack to the hill and over it again!</textarea>" \
       "<input name='post[secret]' type='hidden' value='0' />" \
-      "<input name='post[secret]' checked='checked' type='checkbox' value='1' />"
+      "<input name='post[secret]' checked='checked' type='checkbox' value='1' id='post_secret' />"
 
     assert_dom_equal expected, output_buffer
   end
@@ -1773,10 +1801,10 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     expected =
-      "<input name='post[123][title]' type='text' value='Hello World' />" \
-      "<textarea name='post[123][body]'>\nBack to the hill and over it again!</textarea>" \
+      "<input name='post[123][title]' type='text' value='Hello World' id='post_123_title' />" \
+      "<textarea name='post[123][body]' id='post_123_body'>\nBack to the hill and over it again!</textarea>" \
       "<input name='post[123][secret]' type='hidden' value='0' />" \
-      "<input name='post[123][secret]' checked='checked' type='checkbox' value='1' />"
+      "<input name='post[123][secret]' checked='checked' type='checkbox' value='1' id='post_123_secret' />"
 
     assert_dom_equal expected, output_buffer
   end
@@ -1789,10 +1817,10 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     expected =
-      "<input name='post[][title]' type='text' value='Hello World' />" \
-      "<textarea name='post[][body]'>\nBack to the hill and over it again!</textarea>" \
+      "<input name='post[][title]' type='text' value='Hello World' id='post__title' />" \
+      "<textarea name='post[][body]' id='post__body'>\nBack to the hill and over it again!</textarea>" \
       "<input name='post[][secret]' type='hidden' value='0' />" \
-      "<input name='post[][secret]' checked='checked' type='checkbox' value='1' />"
+      "<input name='post[][secret]' checked='checked' type='checkbox' value='1' id='post__secret' />"
 
     assert_dom_equal expected, output_buffer
   end
@@ -1805,10 +1833,10 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     expected =
-      "<input name='post[abc][title]' type='text' value='Hello World' />" \
-      "<textarea name='post[abc][body]'>\nBack to the hill and over it again!</textarea>" \
+      "<input name='post[abc][title]' type='text' value='Hello World' id='post_abc_title' />" \
+      "<textarea name='post[abc][body]' id='post_abc_body'>\nBack to the hill and over it again!</textarea>" \
       "<input name='post[abc][secret]' type='hidden' value='0' />" \
-      "<input name='post[abc][secret]' checked='checked' type='checkbox' value='1' />"
+      "<input name='post[abc][secret]' checked='checked' type='checkbox' value='1' id='post_abc_secret' />"
 
     assert_dom_equal expected, output_buffer
   end
@@ -1821,10 +1849,10 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     expected =
-      "<input name='post[title]' type='text' value='Hello World' />" \
-      "<textarea name='post[body]'>\nBack to the hill and over it again!</textarea>" \
+      "<input name='post[title]' type='text' value='Hello World' id='post_title' />" \
+      "<textarea name='post[body]' id='post_body' >\nBack to the hill and over it again!</textarea>" \
       "<input name='post[secret]' type='hidden' value='0' />" \
-      "<input name='post[secret]' checked='checked' type='checkbox' value='1' />"
+      "<input name='post[secret]' checked='checked' type='checkbox' value='1' id='post_secret' />"
 
     assert_dom_equal expected, output_buffer
   end
@@ -1837,10 +1865,10 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     expected =
-      "<input name='post[title]' type='text' value='Hello World' />" \
-      "<textarea name='post[body]'>\nBack to the hill and over it again!</textarea>" \
+      "<input name='post[title]' type='text' value='Hello World' id='post_title' />" \
+      "<textarea name='post[body]' id='post_body' >\nBack to the hill and over it again!</textarea>" \
       "<input name='post[secret]' type='hidden' value='0' />" \
-      "<input name='post[secret]' checked='checked' type='checkbox' value='1' />"
+      "<input name='post[secret]' checked='checked' type='checkbox' value='1' id='post_secret' />"
 
     assert_dom_equal expected, output_buffer
   end
@@ -1852,7 +1880,7 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     assert_dom_equal "<label for=\"author_post_title\">Title</label>" \
-    "<input name='author[post][title]' type='text' value='Hello World' />",
+    "<input name='author[post][title]' type='text' value='Hello World' id='author_post_title' id='author_post_1_title' />",
       output_buffer
   end
 
@@ -1863,7 +1891,7 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     assert_dom_equal "<label for=\"author_post_1_title\">Title</label>" \
-      "<input name='author[post][1][title]' type='text' value='Hello World' />",
+      "<input name='author[post][1][title]' type='text' value='Hello World' id='author_post_1_title' />",
       output_buffer
   end
 
@@ -1882,10 +1910,10 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     expected = whole_form("/posts/123", "create-post", method: "patch") do
-      "<input name='post[title]' type='text' value='Hello World' />" \
-      "<textarea name='post[body]'>\nBack to the hill and over it again!</textarea>" \
+      "<input name='post[title]' type='text' value='Hello World' id='post_title' />" \
+      "<textarea name='post[body]' id='post_body' >\nBack to the hill and over it again!</textarea>" \
       "<input name='parent_post[secret]' type='hidden' value='0' />" \
-      "<input name='parent_post[secret]' checked='checked' type='checkbox' value='1' />"
+      "<input name='parent_post[secret]' checked='checked' type='checkbox' value='1' id='parent_post_secret' />"
     end
 
     assert_dom_equal expected, output_buffer
@@ -1902,9 +1930,9 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     expected = whole_form("/posts/123", "create-post", method: "patch") do
-      "<input name='post[title]' type='text' value='Hello World' />" \
-      "<textarea name='post[body]'>\nBack to the hill and over it again!</textarea>" \
-      "<input name='post[comment][name]' type='text' value='new comment' />"
+      "<input name='post[title]' type='text' value='Hello World' id='post_title' />" \
+      "<textarea name='post[body]' id='post_body'>\nBack to the hill and over it again!</textarea>" \
+      "<input name='post[comment][name]' type='text' value='new comment' id='post_comment_name' />"
     end
 
     assert_dom_equal expected, output_buffer
@@ -1918,7 +1946,7 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     expected = whole_form("/posts/123", method: "patch") do
-      "<input name='post[category][name]' type='text' />"
+      "<input name='post[category][name]' type='text' id='post_category_name' />"
     end
 
     assert_dom_equal expected, output_buffer
@@ -1942,9 +1970,9 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     expected = whole_form("/posts/123", method: "patch") do
-      "<label for='title'>Title:</label> <input name='post[title]' type='text' value='Hello World' /><br/>" \
-      "<label for='body'>Body:</label> <textarea name='post[body]'>\nBack to the hill and over it again!</textarea><br/>" \
-      "<label for='secret'>Secret:</label> <input name='post[secret]' type='hidden' value='0' /><input name='post[secret]' checked='checked' type='checkbox' value='1' /><br/>"
+      "<label for='title'>Title:</label> <input name='post[title]' type='text' value='Hello World' id='post_title'/><br/>" \
+      "<label for='body'>Body:</label> <textarea name='post[body]' id='post_body'>\nBack to the hill and over it again!</textarea><br/>" \
+      "<label for='secret'>Secret:</label> <input name='post[secret]' type='hidden' value='0' /><input name='post[secret]' checked='checked' type='checkbox' value='1' id='post_secret' /><br/>"
     end
 
     assert_dom_equal expected, output_buffer
@@ -1961,9 +1989,9 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     expected = whole_form("/posts/123", method: "patch") do
-      "<label for='title'>Title:</label> <input name='post[title]' type='text' value='Hello World' /><br/>" \
-      "<label for='body'>Body:</label> <textarea name='post[body]'>\nBack to the hill and over it again!</textarea><br/>" \
-      "<label for='secret'>Secret:</label> <input name='post[secret]' type='hidden' value='0' /><input name='post[secret]' checked='checked' type='checkbox' value='1' /><br/>"
+      "<label for='title'>Title:</label> <input name='post[title]' type='text' value='Hello World' id='post_title' /><br/>" \
+      "<label for='body'>Body:</label> <textarea name='post[body]' id='post_body'>\nBack to the hill and over it again!</textarea><br/>" \
+      "<label for='secret'>Secret:</label> <input name='post[secret]' type='hidden' value='0' /><input name='post[secret]' checked='checked' type='checkbox' value='1' id='post_secret' /><br/>"
     end
 
     assert_dom_equal expected, output_buffer
@@ -1980,7 +2008,7 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     expected = whole_form("/posts/123", method: "patch") do
-      "<label for='title'>Title:</label> <input name='post[title]' type='text' value='Hello World' /><br/>"
+      "<label for='title'>Title:</label> <input name='post[title]' type='text' value='Hello World' id='post_title' /><br/>"
     end
 
     assert_dom_equal expected, output_buffer
@@ -1995,7 +2023,7 @@ class FormWithActsLikeFormForTest < FormWithTest
       concat f.text_field(:title)
     end
 
-    expected = "<label for='title'>Title:</label> <input name='post[title]' type='text' value='Hello World' /><br/>"
+    expected = "<label for='title'>Title:</label> <input name='post[title]' type='text' value='Hello World' id='post_title' /><br/>"
 
     assert_dom_equal expected, output_buffer
   end
@@ -2007,7 +2035,7 @@ class FormWithActsLikeFormForTest < FormWithTest
       concat f.text_field(:title)
     end
 
-    expected = "<label for='title'>Title:</label> <input name='post[title]' type='text' value='Hello World' /><br/>"
+    expected = "<label for='title'>Title:</label> <input name='post[title]' type='text' value='Hello World' id='post_title' /><br/>"
 
     assert_dom_equal expected, output_buffer
   end
@@ -2020,9 +2048,9 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     expected =
-      "<label for='title'>Title:</label> <input name='post[title]' type='text' value='Hello World' /><br/>" \
-      "<label for='body'>Body:</label> <textarea name='post[body]'>\nBack to the hill and over it again!</textarea><br/>" \
-      "<label for='secret'>Secret:</label> <input name='post[secret]' type='hidden' value='0' /><input name='post[secret]' checked='checked' type='checkbox' value='1' /><br/>"
+      "<label for='title'>Title:</label> <input name='post[title]' type='text' value='Hello World' id='post_title'/><br/>" \
+      "<label for='body'>Body:</label> <textarea name='post[body]' id='post_body'>\nBack to the hill and over it again!</textarea><br/>" \
+      "<label for='secret'>Secret:</label> <input name='post[secret]' type='hidden' value='0' /><input name='post[secret]' checked='checked' type='checkbox' value='1' id='post_secret' /><br/>"
 
     assert_dom_equal expected, output_buffer
   end