add fieldWtihErrors class on wrapper with errors (fixes Issue #3)

lib/generators/simple_form/templates/simple_form.rb

@@ -16,6 +16,9 @@ SimpleForm.setup do |config|
   # You can wrap all inputs in a pre-defined tag.
   # config.wrapper_tag = :div
 
+  # CSS class to add to the wrapper if the field has errors
+  # config.wrapper_errors_class = :fieldWithErrors
+
   # How the label text should be generated altogether with the required text.
   # config.label_text = lambda { |label, required| "#{required} #{label}" }
 

lib/simple_form.rb

@@ -33,6 +33,9 @@ module SimpleForm
   mattr_accessor :wrapper_tag
   @@wrapper_tag = :div
 
+  mattr_accessor :wrapper_errors_class
+  @@wrapper_errors_class = :fieldWithErrors
+
   # How the label text should be generated altogether with the required text.
   mattr_accessor :label_text
   @@label_text = lambda { |label, required| "#{required} #{label}" }

lib/simple_form/components/wrapper.rb

@@ -13,9 +13,15 @@ module SimpleForm
         options[:wrapper_tag] || SimpleForm.wrapper_tag
       end
 
+      def errors_class
+        options[:wrapper_errors_class] || SimpleForm.wrapper_errors_class
+      end
+
       def wrapper_html_options
-        html_options_for(:wrapper, "input", input_type, required_class)
+        css_classes = ["input", input_type, required_class]
+        css_classes << errors_class if object && errors.present?
+        html_options_for(:wrapper, css_classes)
       end
     end
   end
-end
+end

test/components/wrapper_test.rb

@@ -0,0 +1,25 @@
+require 'test_helper'
+
+class WrapperTest < ActionView::TestCase
+  def with_error_for(object, attribute_name, options={}, &block)
+    concat(simple_form_for object do |f|
+      f.options        = options
+      f.input attribute_name
+    end)
+  end
+
+  test 'wrapper should not have error class for attribute without errors' do
+    with_error_for @user, :active
+    assert_no_select 'div.fieldWithErrors'
+  end
+
+  test 'wrapper should not have error class when object is not present' do
+    with_error_for :project, :name
+    assert_no_select 'div.fieldWithErrors'
+  end
+
+  test 'wrapper should add error class for attribute with errors' do
+    with_error_for @user, :name
+    assert_select 'div.fieldWithErrors'
+  end
+end

test/form_builder_test.rb

@@ -288,6 +288,11 @@ class FormBuilderTest < ActionView::TestCase
     assert_select 'form b.required.string'
   end
 
+  test 'builder wrapping tag adds erros class for attribute with errors' do
+    with_form_for @user, :name
+    assert_select 'form div.input.required.string.fieldWithErrors'
+  end
+
   # WITHOUT OBJECT
   test 'builder should generate properly when object is not present' do
     with_form_for :project, :name