4 files changed, 25 insertions, 6 deletions
diff --git a/activemodel/lib/active_model/errors.rb b/activemodel/lib/active_model/errors.rb
index e8bb62953d..abc084a74b 100644
--- a/activemodel/lib/active_model/errors.rb
+++ b/activemodel/lib/active_model/errors.rb
@@ -97,18 +97,19 @@ module ActiveModel
       full_messages = []
 
       each do |attribute, messages|
-        messages = Array.wrap(messages)
+        messages = Array(messages)
         next if messages.empty?
 
         if attribute == :base
           messages.each {|m| full_messages << m }
         else
-          attr_name = @base.class.human_attribute_name(attribute)
-          options = { :default => ' ', :scope => @base.class.i18n_scope }
-          prefix = attr_name + I18n.t(:"errors.format.separator", options)
+          attr_name = attribute.to_s.gsub('.', '_').humanize
+          attr_name = @base.class.human_attribute_name(attribute, :default => attr_name)
+          options = { :default => "{{attribute}} {{message}}", :attribute => attr_name,
+                      :scope => @base.class.i18n_scope }
 
           messages.each do |m|
-            full_messages <<  "#{prefix}#{m}"
+            full_messages << I18n.t(:"errors.format", options.merge(:message => m))
           end
         end
       end
diff --git a/activemodel/lib/active_model/lint.rb b/activemodel/lib/active_model/lint.rb
index 1c2347adbf..0be82aa180 100644
--- a/activemodel/lib/active_model/lint.rb
+++ b/activemodel/lib/active_model/lint.rb
@@ -41,6 +41,20 @@ module ActiveModel
         assert_boolean model.destroyed?, "destroyed?"
       end
 
+      # naming
+      # ------
+      #
+      # Model.model_name must returns a string with some convenience methods as
+      # :human and :partial_path. Check ActiveModel::Naming for more information.
+      #
+      def test_model_naming
+        assert model.class.respond_to?(:model_name), "The model should respond to model_name"
+        model_name = model.class.model_name
+        assert_kind_of String, model_name
+        assert_kind_of String, model_name.human
+        assert_kind_of String, model_name.partial_path
+      end
+
       # errors
       # ------
       #
diff --git a/activemodel/lib/active_model/locale/en.yml b/activemodel/lib/active_model/locale/en.yml
index 0c2cf9ea33..1cdb897f13 100644
--- a/activemodel/lib/active_model/locale/en.yml
+++ b/activemodel/lib/active_model/locale/en.yml
@@ -1,6 +1,9 @@
 en:
   activemodel:
     errors:
+      # model.errors.full_messages format.
+      format: "{{attribute}} {{message}}"
+
       # The values :model, :attribute and :value are always available for interpolation
       # The value :count is available when applicable. Can be used for pluralization.
       messages:
diff --git a/activemodel/lib/active_model/validator.rb b/activemodel/lib/active_model/validator.rb
index 8c9f9c7fb3..01695cb73a 100644
--- a/activemodel/lib/active_model/validator.rb
+++ b/activemodel/lib/active_model/validator.rb
@@ -72,7 +72,8 @@ module ActiveModel #:nodoc:
     attr_reader :attributes
 
     def initialize(options)
-      @attributes = options.delete(:attributes)
+      @attributes = Array(options.delete(:attributes))
+      raise ":attributes cannot be blank" if @attributes.empty?
       super
       check_validity!
     end