Add support to translate action (#594)

Suport translate action name

lib/cancan/unauthorized_message_resolver.rb

@@ -4,7 +4,8 @@ module CanCan
   module UnauthorizedMessageResolver
     def unauthorized_message(action, subject)
       keys = unauthorized_message_keys(action, subject)
-      variables = { action: action.to_s }
+      variables = {}
+      variables[:action] = I18n.translate("actions.#{action}", default: action.to_s)
       variables[:subject] = translate_subject(subject)
       message = I18n.translate(keys.shift, **variables.merge(scope: :unauthorized, default: keys + ['']))
       message.blank? ? nil : message

spec/cancan/ability_spec.rb

@@ -707,6 +707,27 @@ class Account
       end
     end
 
+    it "uses action's name in i18n" do
+      class Account
+        include ActiveModel::Model
+      end
+
+      I18n.backend.store_translations :en,
+                                      actions: { update: 'english name' },
+                                      unauthorized: { update: { all: '%{action}' } }
+      I18n.backend.store_translations :ja,
+                                      actions: { update: 'japanese name' },
+                                      unauthorized: { update: { all: '%{action}' } }
+
+      I18n.with_locale(:en) do
+        expect(@ability.unauthorized_message(:update, Account)).to eq('english name')
+      end
+
+      I18n.with_locale(:ja) do
+        expect(@ability.unauthorized_message(:update, Account)).to eq('japanese name')
+      end
+    end
+
     it 'uses symbol as subject directly' do
       I18n.backend.store_translations :en, unauthorized: { has: { cheezburger: 'Nom nom nom. I eated it.' } }
       expect(@ability.unauthorized_message(:has, :cheezburger)).to eq('Nom nom nom. I eated it.')